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Jugular Venous Pulse Descents Patterns - Recognition and Clinical Relevance:

Open AccessPublished:November 24, 2022DOI:https://doi.org/10.1016/j.cjco.2022.11.016

      Abstract

      Clinical assessment of right heart function and hemodynamics is relevant in many clinical states and may aid quick clinical decision making. With transcutaneous bidirectional Doppler, the jugular venous flow velocity patterns have been shown to reflect right heart hemodynamics and its derangement irrespective of the underlying etiology. Since the peaks in the forward flow velocities in the superior vena cava and the jugulars correspond to the falling slopes of pressure waves namely the " x, x' and y descents " in the right atrium, the patterns of descents in the jugular venous pulse (JVP) become clinically useful for assessment of the right heart function and the right heart hemodynamics. Bedside assessment of the JVP have long been focused on the rise to the peaks of these physiologic waveforms. However, these studies clearly show that the descents which represent the slopes of fall to the nadir (the lowest point) actually hold useful physiologic correlates. The descents in the JVP are fast movements receding from the eye fields and therefore easily seen at the bedside. Based on these studies and long term clinical observations, normal JVP descents pattern is single x' or x' > y and the descents patterns of x' = y, x' < y and single y descent alone are abnormal. The focus of this paper is to discuss in detail these JVP descents patterns both normal and the abnormal with emphasis on clinical relevance. Clinical video recordings of jugular venous pulsations are presented to demonstrate the key points.

      Introduction:

      Mechanisms of venous return and right heart filling have been of interest to clinicians since the days of Harvey

      Harvey W. Exercitatio anatomica de motu cordis et sanguinis in animalibus. Frankfurt, gugliemi fitzeri,1628 (english translation by leake cd,. 1949;ed 3 printing 2 Springfield, Thomas,

      and Purkinje

      Purkinje J. Uber die saugkraft des herzens. Ubbersicht der arbeiten und veranderungen der schlesischen gesellschaft fur vaterlanndische kultur im jahre. 1843:p 147

      . Chauveau and Marey
      • Chauveau A.
      • Marey E.
      Appareilles et experiences cardiographiques per l'emploi des instruments enreistreures a indications continues.
      first published tracings of the venous pulse. Mackenzie
      • Mackenzie J.
      Pulsations in the veins with the description of a method of graphically recording them.
      ,
      • MacKenzie J.
      The interptretation of the pulsations in the jugular veins.
      at the beginning of the last century, introducing his classical polygraph method, studied extensively venous pulsations and helped define the wave forms, their terminology and their origin. He recognized the main waves calling them "a" "c" and "v" to denote the first letters of what he assumed to be their anatomic origins namely the right atrium, the carotid pulse and the right ventricle. He also described the abnormal venous pulse of tricuspid regurgitation as dominated by a systolic "v" wave and termed this "ventricular type venous pulse". Since the days of Mackenzie, clinicians have studied venous pulse and pressure contour in a variety of clinical states.

      Wiggers CJ. Modern aspects of the circulation in health and disease. Philadelphia Lea and Febiger; 1923.

      Lewis T. Diseases of the heart. London: Macmillam Publishing; 1937.

      • MacKay I.
      An experimental analysis of the jugular pulsed in man.
      • Hansen A.
      • Eskildsen P.
      • Gotzsche H.
      Pressure curves from the right auricle and the right ventricle in chronic constrictive pericarditis.
      • Burch G.
      • Ray C.T.
      Mechanism of the hepatojugular reflux test in congestive heart failure.
      • Brecher G.
      Cardiac variations in venous return witha new bristleflow meter.
      • Wilson R.
      • Hoseth W.
      • Sadoff C.
      • Dempsey M.
      Pathologic physiology and diagnostic significance of the pressure pulse tracings in the heart in patients with constrictive pericarditis and pericardial effusion.
      • Reinhold J.
      Venous pulse in atrial septal defect; a clinical sign.
      • Cassio P.
      • Buzzi A.
      Clinical value of the venous pulse.
      • Gibson R.
      Atypical constrictive pericarditis.
      • Hartman H.
      The jugular venous pulse tracing.
      • Perloff J.
      • Harvey P.
      Clinical recognition of tricuspid stenosis.
      • SharpeySchafer E.
      Venous tone.
      • Wood P.
      Chronic constrictive pericarditis.
      • Feder W.
      • Cherry R.
      External jugular phlebogram as reflecting venous and right atrial hemodynamics.
      • Shabetai R.
      • Fowler N.
      • Fenton J.
      • Masangkay M.
      Pulsus paradoxus.
      • Brawley R.K.
      • Oldham H.
      • Vasco J.
      • Henney P.
      • Morrow A.
      Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
      • Lange R.
      • Botticelli J.
      • Tsagaris T.
      • Walker J.
      • Gani M.
      • Bustamine R.
      Diagnostic signs on compressive cardiac disorders, constrictive pericarditis, pericardial effusion and tamponade.
      • Pinkerson A.
      • Luria M.
      • Freis E.
      Effect of cardiac rhythm on vana caval blood flows.

      Wood P. Diseases of the heart and circulation. Philadelphia: Lippincott; 1968.

      • Wexler L.
      • Bergel D.
      • Gabe I.
      • Makin G.
      • Mills C.
      Velocity of blood flow in normal human vanae cavae.

      Gabe I, Gault J, Ross J, Mason D, Mills C, Schillingford J, E B. Measurement of instantaneous blood flow velocity and pressure in conscious man with catheter tip velocity probe. Circulation. 1969;40:603-614

      • Rich L.
      • Tavel M.
      The origin of the jugular c wave.
      • Constant J.
      The x prime descent in jugular contour nomenclature and recognition.
      • Harley A.
      Persistent right atrial standstill.
      • Matsuhisa M.
      • Shimomura K.
      • Beppu S.
      • Nakajima K.
      Post-operative changes of jugular pulse tracing.
      • Jensen D.
      • Goolsby J.
      • Oliva P.
      Hemodynamic pattern resembling pericardial constriction after acute inferior myocardial infraction with right ventricular infarction.
      • Tavel M.
      • Bard R.
      • Franks L.
      • Feigenbaum H.
      • Fisch C.
      The jugular venous pulse in atrial septal defect.
      The advent of cardiac catheterization and direct measurement of intra-cardiac pressures provided an additional dimension in analysis.
      • Hansen A.
      • Eskildsen P.
      • Gotzsche H.
      Pressure curves from the right auricle and the right ventricle in chronic constrictive pericarditis.
      ,
      • Wilson R.
      • Hoseth W.
      • Sadoff C.
      • Dempsey M.
      Pathologic physiology and diagnostic significance of the pressure pulse tracings in the heart in patients with constrictive pericarditis and pericardial effusion.
      ,
      • Perloff J.
      • Harvey P.
      Clinical recognition of tricuspid stenosis.
      ,
      • Wood P.
      Chronic constrictive pericarditis.
      ,
      • Feder W.
      • Cherry R.
      External jugular phlebogram as reflecting venous and right atrial hemodynamics.
      ,
      • Lange R.
      • Botticelli J.
      • Tsagaris T.
      • Walker J.
      • Gani M.
      • Bustamine R.
      Diagnostic signs on compressive cardiac disorders, constrictive pericarditis, pericardial effusion and tamponade.
      ,
      • Jensen D.
      • Goolsby J.
      • Oliva P.
      Hemodynamic pattern resembling pericardial constriction after acute inferior myocardial infraction with right ventricular infarction.
      • Tavel M.
      • Bard R.
      • Franks L.
      • Feigenbaum H.
      • Fisch C.
      The jugular venous pulse in atrial septal defect.
      • Bloomfeld R.
      • Lauson H.
      • Cournand A.
      • Breed E.
      • Richards D.J.
      Recording of right heart pressures in normal subjects and in patients with chronic pulmonary disease and various types of cardio-circulatory disease.
      • Lyons H.
      • Kelly J.
      • Nusbaum N.
      • Dennis C.
      Right atrial myxoma. A clinical study of a patient in whom diagnosis was made by angiography during life (surgically removed).
      • Kesteloot H.
      • Denef B.
      Value of reference tracing in diagnosis and assessment of constrictive,epi and pericarditis.
      The development of techniques to study blood flow velocity made further substantial contribution to our understanding of the mechanisms of venous return and right heart filling.
      • Brecher G.
      Cardiac variations in venous return witha new bristleflow meter.
      ,
      • Shabetai R.
      • Fowler N.
      • Fenton J.
      • Masangkay M.
      Pulsus paradoxus.
      ,
      • Brawley R.K.
      • Oldham H.
      • Vasco J.
      • Henney P.
      • Morrow A.
      Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
      ,
      • Pinkerson A.
      • Luria M.
      • Freis E.
      Effect of cardiac rhythm on vana caval blood flows.
      ,
      • Wexler L.
      • Bergel D.
      • Gabe I.
      • Makin G.
      • Mills C.
      Velocity of blood flow in normal human vanae cavae.
      ,

      Gabe I, Gault J, Ross J, Mason D, Mills C, Schillingford J, E B. Measurement of instantaneous blood flow velocity and pressure in conscious man with catheter tip velocity probe. Circulation. 1969;40:603-614

      ,
      • Froysaker T.
      Abnormal flow pattern in the superior vena cava induced by arrhythmias . A perioperative flowmetric study in man.
      • Kalmanson D.
      • Veyrat C.
      • Chiche P.
      Atrial versus ventricular contribution in determining systolic venous return. A new approach to an old riddle.
      • Benchimol A.
      • Desser K.
      • Gartlan J.
      Bidirectional blood flow velocity in the cardiac chambers and great vessels studied with the doppler ultrasonic flowmeter.
      • Matsuo H.
      • Nimura Y.
      • Kitabatake A.
      • Hayashi T.
      Analysis of flow patterns in blood vessels with the directional ultrasonic doppler technique through a transcutaneous approach.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      • Shabetai R.
      • Fowler N.
      • Guntheroth W.
      The hemodynamics of cardiac tamponade and constrictive pericarditis.
      • Rittenhouse E.
      • Barnes R.
      Hemodynamics of cardiac tamponade : Early recognition from jugular vnous flow velocity.
      • Nelson R.
      • Jenson C.
      • Smoot W.
      Pericardial tamponande following open heart suregry.
      Using the transcutaneous bidirectional Doppler technique, we had previously presented a systematic classification and correlation of jugular venous flow velocity patterns with both normal and abnormal states of right heart hemodynamics.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      The application of these findings to clinical assessment and practice is the subject of this review. Three clinical video recordings of the jugular venous pulsations included in this paper will assist in demonstrating the key points.

      I. Normal Physiology of Right Atrial Pressure Pulse waves:

      The pressure in the right atrium at the end of diastole before atrial contraction occurs is normally equal to the diastolic pressure in the right ventricle (in the absence of tricuspid stenosis - which is very rare). This pre "a" wave pressure sets the base line over which the "a" wave and the "v" wave pressures rise in the right atrium. The pre "a" wave right ventricular diastolic pressure is influenced by the volume status of the patient as well as by the diastolic compliance characteristics of the right ventricle and the surrounding pericardium (normally close to 0 to 2 mmHg). In normal patients in sinus rhythm, the "a" wave is formed by right atrial contraction followed by atrial relaxation. Since the descents in the right atrial (and by implication in the JVP) are all named, the falling slope of the "a" wave caused by active atrial relaxation has been termed the x descent (Fig.1A). The next event in the cardiac cycle is the powerful ventricular systole. In most patients with intact tricuspid valve function this is associated with a steep slope of fall in the right atrial pressure termed the x prime (x') descent
      • Constant J.
      The x prime descent in jugular contour nomenclature and recognition.
      (Fig.1B). The x' descent is preserved in atrial fibrillation as well as in atrial standstill.
      • Harley A.
      Persistent right atrial standstill.
      It is due to the floor of the atrium formed by the closed tricuspid valve actively being pulled down causing expansion of the right atrium and a rapid drop in the right atrial pressure. One can see this active systolic downward movement of the base of the heart (the tricuspid and the mitral annular plane) in cine coronary angiogram of the right coronary artery (RCA). One can also see the tricuspid annular plane moving towards the apex actively during systole in the apical four chamber views of the 2D echocardiographic images, measured as "TAPSE".
      • Aloia Elio
      • Cameli Matteo
      • D'Ascenzi Flavio
      • Sciaccaluga Carlotta
      • Mondillo S.
      Tapse: An old but useful tool in different diseases.
      ,
      • Ghio S.R.
      • Klersy C.
      • Sebastiani M.
      • Laudisa M.L.
      • Campana C.
      • Tavazzi L.
      Prognostic usefulness of the tricuspid annular plane systolic excursion in patients with congestiove heart failure secondary to idiopathic or ischemic dilated cardiomyopathy.
      The right ventricular systolic function and its ejection output are mostly dependent on this longitudinal shortening from base towards the apex.
      Figure thumbnail gr1
      Figure.1A and B: Jugular Venous Pulse (JVP) recording in a patient with coronary artery disease and normal right heart function taken simultaneously with recording of right ventricular (RV) and right atrial (RA) pressures. The x descent in the JVP is due to atrial relaxation following the summit of the "a" wave formed by atrial contraction during sinus rhythm. The x' descent occurs during ventricular systole with rising right ventricular pressure. The diagram in 1B, shows the closed tricuspid valve forming the floor of the right atrium being pulled down towards the apex during systole. Thick arrow represents the accelerating jugular venous flow velocity during systole. : Superior vena caval flow (SVC Fl) velocity recording shown in 1C with simultaneous ECG, Carotid pulse (CP) and right atrial (RA) pressures with phonocardiogram at the bottom showing the second heart sound (S2). The systolic flow velocity peak (Sf) is more prominent than the diastolic flow (Df) peak in this adult patient with coronary artery disease with normal right heart function. The Sf peak corresponds to the nadir of the x' descent in the right atrial (RA) pressures occurring in the middle of systole. D: is from the same patient with Jugular Venous Flow (JVF) velocity recording obtained transcutaneously. The flow velocity patterns are similar to SVC Fl. The Sf in JVF peaks close to the end of systole due to the transmission delay to the neck almost synchronizing with the S2
      The rapid fall in the right atrial pressure during systole (x' descent) leads to an accelerated flow velocity in the superior vena cava as well as in the jugulars. The systolic venous flow into the right atrium leads to a slow build of normal "v" wave in the right atrial pressure. At the end of systole, when the right ventricle begins to actively relax and expand dropping its pressure to almost zero, the tricuspid valve opens and the right atrium begins to empty initially somewhat rapidly during the rapid filling phase and slowly over the slow filling phase. This diastolic filling of the right ventricle is associated with a falling slope of the right atrial "v" wave and it is termed as the y descent. In the normal subjects, while the y descent is often seen in the right atrial pressure pulse recordings, it may not be seen in the internal jugular venous pulsations. This is explained by the fact that the right atrium is a capacitance chamber. Due to that capacitance function, as it empties in diastole into the right ventricle, it can accommodate that volume loss without transmitting the resultant pressure fluctuations to the superior vena cava and the jugulars. Therefore in the normal adult patients, jugular contour often may be just a single x' descent. At the end of diastole, the filling of the right ventricle is aided by active contraction of the right atrium during sinus rhythm. This active right atrial contraction leads to the rising slope of the normal "a" wave in the right atrium of the next cardiac cycle. The foregoing description of the normal physiology of the right atrial pressure pulse waves indicates that during normal sinus rhythm there are three descents in the right atrial pressure pulse namely the x descent, the x' descent and the y descent.

      II. Jugular Venous Flow Velocity Patterns and Descents:

      Three previously reported pivotal studies of jugular venous flow velocity patterns using the transcutaneous bidirectional Doppler technique combined with long term clinical observations form the basis of this paper.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      The first of these three studies was carried out in 174 patients with a variety of cardiac conditions (54 with ischemic heart disease, 68 with valvular heart disease, 19 with congenital heart lesions, 17 with cardiomyopathy, 8 with pericardial disease, 5 with pulmonary hypertension and 3 with myxoma). Eighty two of the 174 patients had hemodynamic measurements made during diagnostic cardiac catheterization with the Doppler jugular venous flow studies carried out within 24 hours of the diagnostic catheterization.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      The two subsequent studies, were aimed to clarify the mechanisms underlying the alterations in flow patterns associated with pulmonary hypertension and open-heart surgery.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      ,
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      The pulmonary hypertension study consisted of 25 patients with significant pulmonary hypertension confirmed by cardiac catheterization (severe in 15 patients with pulmonary systolic pressure >80mmHg, moderate in 5 patients (60 -79 mm Hg) and mild in 5 patients (40-59 mmHg).
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      The study to characterize and assess the mechanism behind the changes in jugular venous flow velocity patterns associated with open heart surgery were carried out in 25 patients (19 men and 6 women ages 29 to 71 years) all of whom underwent coronary artery bypass grafting surgery.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      In each of these studies, all forward flow velocity patterns towards the heart are depicted in the Doppler tracings as upward deflections above the zero base line.
      The initial study (with a variety of cardiac conditions and correlation to right heart hemodynamics) demonstrated clearly that the flow velocity patterns and their variations reflect right heart hemodynamics and its derangement irrespective of the underlying etiology.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      The peaks in the flow velocity in the superior vena cava as well as in the jugulars correspond to the falling slopes of pressure waves in the right atrium namely the x, x' and y descents. The flow velocity curves are similar in both the superior vena cava and the internal jugular veins in the neck except for a slight transmission delay to the neck.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      The steepness in the peak velocities of the jugular venous flow reflects the steepness of the descents of the pressure pulse. Jugular venous flow velocity in normal subjects is similar to flow velocity in the superior vena cava with a dominant flow in systole namely systolic flow velocity (Sf) > the diastolic flow velocity (Df).11 26, 39, 40 41 This corresponds to the more dominant x' descent than the y descent in the right atrium (as well as in the jugulars) of normal subjects (Fig.1C and 1D). Diagrammatic representation of the different flow velocity patterns and the corresponding JVP descents patterns are shown in (Fig. 2).
      Figure thumbnail gr2
      Figure.2Diagrammatic representation of different flow velocity patterns both normal and abnormal and their temporal relationship during the cardiac cycle shown along with the corresponding descents pattern in the jugular venous pulse. In the pt with normal right heart function, the systolic flow (Sf) is more dominant than the diastolic flow (Df) and in the JVP, the descent pattern is x' > y. Ret Sf = Retrograde Flow into the Jugulars during systole with significant tricuspid regurgitation. Ret Df = Retrograde Flow into the Jugulars during diastole from strong right atrial contraction.
      While there is no controversy about diastolic inflow following the tricuspid valve opening, controversy and discussion have long centered around the cause of the more dominant systolic flow velocity in normal subjects
      • Brecher G.
      Cardiac variations in venous return witha new bristleflow meter.
      ,
      • Brawley R.K.
      • Oldham H.
      • Vasco J.
      • Henney P.
      • Morrow A.
      Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
      ,
      • Pinkerson A.
      • Luria M.
      • Freis E.
      Effect of cardiac rhythm on vana caval blood flows.
      ,
      • Wexler L.
      • Bergel D.
      • Gabe I.
      • Makin G.
      • Mills C.
      Velocity of blood flow in normal human vanae cavae.
      ,
      • Kalmanson D.
      • Veyrat C.
      • Chiche P.
      Atrial versus ventricular contribution in determining systolic venous return. A new approach to an old riddle.
      ,
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      . Our observations and the previous studies support the concept that systolic flow velocity is caused by two factors, namely atrial relaxation
      • Brawley R.K.
      • Oldham H.
      • Vasco J.
      • Henney P.
      • Morrow A.
      Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
      ,
      • Pinkerson A.
      • Luria M.
      • Freis E.
      Effect of cardiac rhythm on vana caval blood flows.
      and the descent of the base of the right ventricle (tricuspid valve ring with the closed tricuspid valve) during active ventricular systole, the latter being the dominant factor.
      • Brecher G.
      Cardiac variations in venous return witha new bristleflow meter.
      ,
      • Wexler L.
      • Bergel D.
      • Gabe I.
      • Makin G.
      • Mills C.
      Velocity of blood flow in normal human vanae cavae.
      ,
      • Kalmanson D.
      • Veyrat C.
      • Chiche P.
      Atrial versus ventricular contribution in determining systolic venous return. A new approach to an old riddle.
      ,
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      . Atrial relaxation flow is shown to occur during periods of atrio-ventricular dissociation or when the PR interval is long.
      • Brawley R.K.
      • Oldham H.
      • Vasco J.
      • Henney P.
      • Morrow A.
      Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
      ,
      • Pinkerson A.
      • Luria M.
      • Freis E.
      Effect of cardiac rhythm on vana caval blood flows.
      ,
      • Kalmanson D.
      • Veyrat C.
      • Chiche P.
      Atrial versus ventricular contribution in determining systolic venous return. A new approach to an old riddle.
      ,
      • Benchimol A.
      • Desser K.
      • Gartlan J.
      Bidirectional blood flow velocity in the cardiac chambers and great vessels studied with the doppler ultrasonic flowmeter.
      ,
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      In normal subjects, atrial relaxation flow is only seen on Doppler tracings as a notch on the upstroke of systolic flow velocity corresponding to the x descent (where as the peak of Sf as confirmed by internal pressure and flow recordings always corresponds to the x' (x prime) descent.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      (Fig.1). The latter is due to the contracting ventricle. The drop in atrial pressure may be facilitated by the fall in pericardial pressures that occurs when the volume of the heart decreases during systole.
      • Holt J.P.
      • Rhode E.A.
      • Kines H.
      Pericardial and ventricular pressure.
      Alterations from this normal dominant systolic flow velocity (Sf > Df) pattern resulting from various pathologies include the flow velocity patterns of Sf = Df , Sf < Df , and Df alone. In the hemodynamic studies, they were all shown to be abnormal forward flow velocity patterns.
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      (Fig.2). They correspond to the descents patterns of x' = y or x' < y and single y descent in the contour of the right atrial pressures. The majority of the patients with abnormal flow patterns and pulmonary hypertension had increased right atrial "v" wave pressures implying that the Df velocity must be increased.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      This was shown to be due to an increased right ventricular early diastolic and pre-A wave pressures. Decreased Sf and Df alone patterns (corresponding respectively to x' < y and single y descent) were associated with congestive heart failure and appeared later in the course, in serial observations.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      In most patients who had undergone cardiopulmonary bypass however, the altered flow velocity patterns and descents are not associated with alterations in right heart hemodynamics.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.
      Observations suggest that postoperatively the right atrium seems to behave like a conduit rather than a capacitance chamber. Its capacitance function is likely attenuated in early postoperative period due to edema and later on probably due to stiffness caused by scarring. The loss of buffering effect of the right atrium as a capacitance chamber leads to full reflection of the Df velocity at the tricuspid valve to the superior vena cava and the jugulars. When the flow pattern was Sf < Df, the right ventricular systolic dysfunction with decreased ejection fraction was demonstrated.
      • Ranganathan N.
      • Sivaciyan V.
      • Pryszlak M.
      • Freeman M.S.
      Changes in jugular venous flow velocity after coronary artery bypass grafting.

      III. Clinical Recognition and Relevance:

      i. Method of Assessment of Descents in JVP:

      Generally, the clinical teaching is to look for the internal jugular venous pulsations transmitted to the surface of the neck overlying the region of the sterno-mastoid muscle recognizing that the latter has two attachments one to the clavicle and the other to the sternum medially. They may be best seen in the small shallow space between the two heads of the sterno-mastoid. It is recommended to have a light source, preferably, from the side to cast a shadow over this region. This brings the pulsations into clear view. The internal jugular venous pulsations will be recognized by the movement of the edge of the shadow. With practice while most students and trainees will be able to identify the upper level of the pulsations and estimate the height of the venous pressure, many will be unable to describe the JVP contours in a way that will be useful clinically. This may be because of lack of understanding of what is being observed. Stressing the usefulness of "the descents" which are the slopes of fall to the nadir (the lowest point) will be of help in this regard. All of the descents are named and have physiologic correlates as described earlier. Recognition of the descents and their patterns are not only the most useful clinically but they are also most easily accomplished. The descents are fast movements and they recede from our eye fields as we look at them and therefore are easily observed. On the other hand, the rises of the jugular "a" and "v" waves are slow and the summits often are also not high especially in the normal subjects. They are therefore hard to recognize. The descents can also be easily timed to either systole or diastole by palpating the arterial pulse simultaneously. (We prefer radial arterial pulse especially when teaching students since it allows unobstructed view of the whole neck region for looking for descents). In the normal subject, one should expect just to see a single x' descent (the fast receding movement of the venous pulse overlying the region of the sterno-mastoid). Since it occurs with systolic contraction of the right ventricle, it will coincide with the arterial pulse. If one wishes to check the timing with the heart sounds, x' descent will fall onto the second heart sound (S2). The sequence is "descent – S2". One sees the descent and hears almost immediately the second heart sound. The y descent on the other hand occurs in diastole and therefore will be asynchronous with the arterial pulse upstroke and will occur clearly after S2 is heard. The sequence will be "S2 – descent" namely one will hear the S2 and then see the descent following it.

      ii. Descents in JVP with Normal Right Heart Function:

      In patients with normal right heart function and pressures, one expects to see single x' descent alone. If y descent is also noted to be present along with x' descent, as may be seen in children, young adults and pregnant patients, the x' descent will be dominant. In young children the rapid circulatory state with relatively smaller atrial sizes, will allow build up of "v" wave thereby exaggerating the y descent. The pattern, in patients with normal right heart hemodynamics, will therefore be either single x' or x' > y. A good x' descent means good right ventricular contraction and therefore normal right ventricular systolic function no matter what the underlying condition is (Video -1). The x descent which occurs with right atrial relaxation in the presence of normal PR intervals is often the initial part of the single systolic x' descent and the two descents become merged. Sometimes, one may observe what looks like a minor hesitation as the systolic x' descent begins its fall indicating the x and the x' components. Rarely if the PR interval is significantly prolonged, one may actually see a separate x descent immediately preceding the dominant x' descent. The descent pattern will be x < x'. This patient was in sinus rhythm with a PR interval of 0.36 seconds. The descent pattern is clearly demonstrated in the video (Video-2). It is easily distinguishable from a y descent which should occur in diastole following the arterial pulse or the S2 and therefore following the systolic x' descent.

      iii. JVP with Double Descents:

      Double descents whether x' > y, x' = y or x' < y generally arise either because x' descent is decreased or the y descent is exaggerated or both, similar to the corresponding flow velocity peaks (Fig.2). If the jugular contour suggests equally prominent slopes of fall of x' as well as y descents, the pattern is termed x' = y. The presence of the "v" wave is deduced when there is a dominant y descent irrespective of whether the rise of the "v" wave is clearly visible or not. The pattern x' = y indicates immediately two things. The first point is that the preserved and good x' descent means that the right ventricular systolic function is likely still good and that there is "no significant" tricuspid regurgitation. The second point is that the y descent is most likely exaggerated. The causes of decreased x' descent and exaggerated y descent are listed in Table.1. Decreased x' descent implies diminished right ventricular contraction. Exaggerated y descent requires increased right atrial "v" wave pressure without any restriction to ventricular filling during the rapid filling phase of diastole. Both of these conditions are met under the following circumstances (Table 1): 1. high sympathetic tone with rapid circulation as in children and young adults, anxiety, anemia, pregnancy and thyrotoxicosis; 2. hypervolemia; 3. extrasource of venous filling as in atrial septal defect; 4. pericardial effusion without tamponade but with some restriction; 5. constrictive pericarditis; 6. pulmonary hypertension with elevated right ventricular diastolic pressures; 7. ischemic or infarcted right ventricle; 8. cardiomyopathy with elevated right ventricular diastolic pressures; 9. in post cardiac surgery patients (where the y descent is exaggerated but the "v" wave pressure is not usually elevated most likely from the changes in the capacitance function of the right atrium as pointed out earlier). While the y descent may be exaggerated with higher "v" wave pressures in patients with pericardial effusion, if it is dominant or equally dominant (namely if the pattern is x' < y or x' = y) then one can exclude immediately cardiac tamponade at the time of the assessment. In cardiac tamponade, the four chambers of the heart are boxed in a pericardial sac with fluid or blood with high intra-pericardial pressures. The blood can enter this boxed heart only when the blood leaves the box namely during systole. Diastolic filling of the ventricles from the atria is quite compromised and can occur only by passive transfer across the open tricuspid and mitral valves during diastole. Therefore one will not expect to see any descents let alone diastolic y descent. The jugular veins will be truly distended with very little pulsations and the top of the column could be well above the neck region. With great difficulty, one may be able to record systolic flow in the jugulars or the superior vena cava towards the heart and that too during inspiration.
      • Rittenhouse E.
      • Barnes R.
      Hemodynamics of cardiac tamponade : Early recognition from jugular vnous flow velocity.
      Therefore in following patients with pericardial effusion, the presence of a good y descent, is a very helpful and easily assessable clinical bed side sign favoring logically the absence of cardiac tamponade. It becomes a useful clinical sign for follow up of patients with pericardial effusion.
      Table 1Causes of Decreased x' descent and Exaggerated y descent
      Decreased x' descent:

      1. Diminished right ventricular (RV) Contraction, e.g., a. RV Failure in pulmonary hypertension

      b. Post-Cardiac Surgery RV damage

      c. RV infarction

      2. Atrial Fibrillation due to loss of Starling Effect

      3. Bernheim effect in severe mitral regurgitation*
      Exaggerated y descent**:

      1. Increased v wave pressure with NO restriction to ventricular filling during rapid filling phase, e.g.,

      a. High sympathetic tone as in young children,

      anxiety, anemia, pregnancy, thyrotoxicosis

      b. Hypervolemia

      c. Extra-source of venous filling as in atrial septal defect

      d. Pericardial effusion with some restriction

      e. Constrictive pericarditis

      f. Pulmonary hypertension with elevated RV diastolic pressure

      g. Ischemic and/or Infarcted RV

      h. Cardiomyopathy
      2. Decreased right atrial capacitance function, e.g., Post-cardiac surgery

      3. Bernheim effect in severe mitral regurgitation*
      * = Rare occurrence
      ** = Excludes Cardiac Tamponade
      Since double descents in the jugulars (x' > y, x' = y and x' < y) mentioned above could also be noted in patients with pulmonary hypertension, one needs to look for clinical signs of pulmonary hypertension. If the patient were to have clinical signs of pulmonary hypertension (palpable P2 in the 2nd left intercostal space near the left sternal margin, sustained right ventricular impulse felt by sub-xiphoid palpation together with electrocardiographic evidence of right axis deviation or right ventricular hypertrophy), the presence of x' = y descent pattern in the jugulars will correlate with significant pulmonary hypertension with pulmonary arterial systolic pressure of 75mmHg or more
      • Sivaciyan V.
      • Ranganathan N.
      Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
      (Video-3). Furthermore the preserved x' descent will indicate preserved right ventricular systolic function with no or only mild tricuspid regurgitation. The exaggerated y descent would imply however elevated right ventricular pre "a" wave and early diastolic pressures. Patients with double descents with x' = y pattern and elevated venous pressures with no clear cut clinical signs of pulmonary hypertension would warrant imaging assessment including Doppler assessment with 2D-echocardiography to rule out pulmonary hypertension. If double descents are noted and the pattern happens to be x' < y, then it indicates decreased right ventricular systolic function with perhaps some tricuspid regurgitation as well. Mild tricuspid regurgitation will not totally eliminate the systolic x' descent. However significant tricuspid regurgitation will do so and result in large actively rising wave termed the "cv" wave during systole followed by a single y descent. The jugular pulsations with such pattern will be visible from several feet away from the patient with patient sitting up. In the presence of significant pulmonary hypertension, serial observations of JVP descents patterns reflect the progression from a compensated state to decompensation with right ventricular failure.
      • Ranganathan N.
      • Sivaciyan V.
      Abnormalities in jugular venous flow velocity in pulmonary hypertension.
      In the early compensated state with right ventricular hypertrophy and preserved systolic function the JVP descents will show dominant (x' > y) which eventually change to x' = y with further elevation of the right ventricular diastolic pressures. With further progression and onset of right ventricular systolic dysfunction the dominant y descent pattern will emerge (x' < y) and eventually with further deterioration and right ventricular dilatation, the contour will change to large "cv" waves with single y descent.
      Very rarely, in some patients with severe mitral regurgitation, the jet of regurgitation directed towards the inter-atrial septum, may result in inter-atrial septal bulge into the right atrium during systole. This may diminish the full effect of the descent of the base on the right atrium resulting in decreased x' descent. This decrease in x' descent is explained by a "Bernheim" type effect on the atrial septum
      • Ranganathan N.
      • Sivaciyan V.
      Jugular venous flow velocity pattern application to bedside recognition of jugular venous pulse contour and right heart hemodynamics.
      ,

      Ranganathan N, Sivaciyan V, Saksena FB. The art and science of cardiac physical examination with heart sounds, jugular and precordial pulsations on cd includes 12-lead ecg interpretation. New Delhi,London, Philadelphia, Panama JAYPEE The Health Sciences Publisher; 2016.

      . In such patients, the y descent may be exaggerated as well without significant elevation of the v wave pressure by the sudden emptying of the left atrium and reversal of the systolic bulge of the inter-atrial septum.
      Differential diagnosis of JVP with double descents in the adult patients therefore requires consideration of the various conditions listed in Table 1 with and without the presence of pulmonary hypertension.

      iv. JVP with Prominent Rises of waves:

      Unlike normal "a" and "v" waves with low pressures and relatively slow rises which are often not seen in the neck, when they are abnormal with higher pressures and sharp rises, one may be able to see them. Marked tricuspid regurgitation with large tall "cv" waves were referred to previously. They are associated with retrograde systolic flow away from the right atrium towards the superior vena cava and the internal jugulars. The large tall "cv" wave will rise with the arterial pulse followed by a single y descent which will fall in diastole after the arterial pulse is no longer felt by the palpating hand. The descent therefore will fall after S2 and timed to be asynchronous with the arterial pulse. Unlike the "cv" waves with longer duration, prominent "a" waves often have sharp quick rises due to short duration of the atrial systole. They may be noted in the presence of atrio-ventricular dissociation as in complete A-V block due to atrial contraction against the closed tricuspid valve secondary to simultaneous ventricular contraction. In this instance, they will be irregular. The sharp rises will attract the eyes and are associated with retrograde flow in the superior vena cava and the jugulars. They are termed "cannon waves" and typically they have short duration. Rarely in patients with severe pulmonary stenosis and in patients with early stages of significant pulmonary hypertension with preserved right atrial function, one may also see regular prominent "a" waves with retrograde flow from the right atrium to the jugulars. Typically it will be with sharp rises and short durations and are followed immediately by good x' descent indicating preserved right ventricular systolic function (Fig.2).

      v. JVP Descents in Atrial Fibrillation:

      Atrial fibrillation is a fairly common arrhythmia encountered in clinical practice. The atrial contraction acts as a boost to the ventricular contraction and sometimes may contribute up to one fourth of the ventricular output. The atrial kick will be lost in atrial fibrillation irrespective of the background cardiac condition and its etiology. The arrhythmia is well known to produce irregularly irregular peripheral pulse. If the underlying right ventricular function is relatively normal the rhythm by itself will not lead to elimination of the x' descent. The varying diastolic intervals with resultant variations in the diastolic filling will affect the systolic outputs to vary from beat to beat. If the right ventricular function is preserved one may still see preserved x' descent in the context of irregular pulse. However, more often atrial fibrillation will develop in patients with underlying heart disease with compromised biventricular function. In such patients the irregular pulse will be accompanied by a single y descent. It will be clearly discerned in beats followed by long diastolic pause.

      Conclusion:

      In conclusion, proper clinical assessment of the JVP requires clear focus on the descents and their patterns as described here. It provides much more useful information about the right heart function than the simple assessment of the patient's volume status by looking at only the height of the jugular venous pressure. It is easy to do and easy to teach even for beginners. It is important to realize also that the relationship between the x' and the y descents in patients with double descents do not alter even when the volume status is altered by either diuretics or by volume infusion
      • Ranganathan N.
      • Sivaciyan V.
      Jugular venous flow velocity pattern application to bedside recognition of jugular venous pulse contour and right heart hemodynamics.
      . That is an added clinical advantage. In addition, the descents patterns provide quick glimpse into the state of right ventricular function and help in clinical diagnosis. Classical example of this is the ability to diagnose constrictive pericarditis at the bedside in patients presenting with congestive symptoms. Other examples include patients presenting with acute inferior infarction or patients presenting with acute myocardial infarction with heart failure symptoms. Finally when the jugular descents pattern is abnormal, consideration of both the causes of decreased x' descent and exaggerated y descent as discussed in this paper will help in the proper clinical evaluation of the patient at hand.

      Acknowledgement:

      We wish to express our sincere thanks to our colleague and friend Mr. Roger Harris, ex -chief of the audio-visual department of St. Joseph' Health Centre of Unity Health Toronto (30, The Queensway, Toronto, Ontario, Canada) for his help in the preparation of the illustrations.

      Supplementary data

      References

      1. Harvey W. Exercitatio anatomica de motu cordis et sanguinis in animalibus. Frankfurt, gugliemi fitzeri,1628 (english translation by leake cd,. 1949;ed 3 printing 2 Springfield, Thomas,

      2. Purkinje J. Uber die saugkraft des herzens. Ubbersicht der arbeiten und veranderungen der schlesischen gesellschaft fur vaterlanndische kultur im jahre. 1843:p 147

        • Chauveau A.
        • Marey E.
        Appareilles et experiences cardiographiques per l'emploi des instruments enreistreures a indications continues.
        Mem Acad Med. 1863; 26: 263
        • Mackenzie J.
        Pulsations in the veins with the description of a method of graphically recording them.
        J Pathol Bacteriol. 1893; 1: 53-89
        • MacKenzie J.
        The interptretation of the pulsations in the jugular veins.
        Am J Med Sci. 1907; 134: 12-34
      3. Wiggers CJ. Modern aspects of the circulation in health and disease. Philadelphia Lea and Febiger; 1923.

      4. Lewis T. Diseases of the heart. London: Macmillam Publishing; 1937.

        • MacKay I.
        An experimental analysis of the jugular pulsed in man.
        J Physiol (Lond). 1947; 106: 113-118
        • Hansen A.
        • Eskildsen P.
        • Gotzsche H.
        Pressure curves from the right auricle and the right ventricle in chronic constrictive pericarditis.
        Circulation. 1951; 3: 881-888
        • Burch G.
        • Ray C.T.
        Mechanism of the hepatojugular reflux test in congestive heart failure.
        Am Heart J. 1954; 48: 373-382
        • Brecher G.
        Cardiac variations in venous return witha new bristleflow meter.
        Am J Physiol. 1954; 111176: 423-430
        • Wilson R.
        • Hoseth W.
        • Sadoff C.
        • Dempsey M.
        Pathologic physiology and diagnostic significance of the pressure pulse tracings in the heart in patients with constrictive pericarditis and pericardial effusion.
        Am Heart J. 1954; 48: 671-683
        • Reinhold J.
        Venous pulse in atrial septal defect; a clinical sign.
        Br Med J. 1955; 1: 695-698
        • Cassio P.
        • Buzzi A.
        Clinical value of the venous pulse.
        Am Heart J. 1957; 54: 127-137
        • Gibson R.
        Atypical constrictive pericarditis.
        Br Heart J. 1959; 21: 583
        • Hartman H.
        The jugular venous pulse tracing.
        Am Heart J. 1960; 59: 698-717
        • Perloff J.
        • Harvey P.
        Clinical recognition of tricuspid stenosis.
        Circulation. 1960; 22: 346-364
        • SharpeySchafer E.
        Venous tone.
        Br Med J. 1961; 2: 1589-1595
        • Wood P.
        Chronic constrictive pericarditis.
        Am J Cardiol. 1961; 7: 48-61
        • Feder W.
        • Cherry R.
        External jugular phlebogram as reflecting venous and right atrial hemodynamics.
        Am J Cardiol. 1963; 12: 383-393
        • Shabetai R.
        • Fowler N.
        • Fenton J.
        • Masangkay M.
        Pulsus paradoxus.
        J Clin Invest. 1965; 44: 1882-1898
        • Brawley R.K.
        • Oldham H.
        • Vasco J.
        • Henney P.
        • Morrow A.
        Influence of right atrial pressure pulse on instantaneous vena caval blood flow.
        Am J Physiol. 1966; 211: 347-353
        • Lange R.
        • Botticelli J.
        • Tsagaris T.
        • Walker J.
        • Gani M.
        • Bustamine R.
        Diagnostic signs on compressive cardiac disorders, constrictive pericarditis, pericardial effusion and tamponade.
        Circulation. 1966; 33: 763-777
        • Pinkerson A.
        • Luria M.
        • Freis E.
        Effect of cardiac rhythm on vana caval blood flows.
        Am J Physiol. 1966; 210: 505-508
      5. Wood P. Diseases of the heart and circulation. Philadelphia: Lippincott; 1968.

        • Wexler L.
        • Bergel D.
        • Gabe I.
        • Makin G.
        • Mills C.
        Velocity of blood flow in normal human vanae cavae.
        Circ Res. 1968; 23: 349-359
      6. Gabe I, Gault J, Ross J, Mason D, Mills C, Schillingford J, E B. Measurement of instantaneous blood flow velocity and pressure in conscious man with catheter tip velocity probe. Circulation. 1969;40:603-614

        • Rich L.
        • Tavel M.
        The origin of the jugular c wave.
        N Engl J Med. 1971; 284: 1309-1311
        • Constant J.
        The x prime descent in jugular contour nomenclature and recognition.
        Am Heart J. 1974; 88: 372-379
        • Harley A.
        Persistent right atrial standstill.
        Br Heart J. 1976; 38: 646-649
        • Matsuhisa M.
        • Shimomura K.
        • Beppu S.
        • Nakajima K.
        Post-operative changes of jugular pulse tracing.
        J Cardiogr. 1976; 6: 403-412
        • Jensen D.
        • Goolsby J.
        • Oliva P.
        Hemodynamic pattern resembling pericardial constriction after acute inferior myocardial infraction with right ventricular infarction.
        Am J Cardiol. 1978; 42: 858-861
        • Tavel M.
        • Bard R.
        • Franks L.
        • Feigenbaum H.
        • Fisch C.
        The jugular venous pulse in atrial septal defect.
        Arch Intern Med. 1968; 121: 524-529
        • Bloomfeld R.
        • Lauson H.
        • Cournand A.
        • Breed E.
        • Richards D.J.
        Recording of right heart pressures in normal subjects and in patients with chronic pulmonary disease and various types of cardio-circulatory disease.
        J Clin Invest. 1946; 25: 639-664
        • Lyons H.
        • Kelly J.
        • Nusbaum N.
        • Dennis C.
        Right atrial myxoma. A clinical study of a patient in whom diagnosis was made by angiography during life (surgically removed).
        Am J Med. 1958; 25: 321-326
        • Kesteloot H.
        • Denef B.
        Value of reference tracing in diagnosis and assessment of constrictive,epi and pericarditis.
        Br Heart J. 1970; 32: 675-682
        • Froysaker T.
        Abnormal flow pattern in the superior vena cava induced by arrhythmias . A perioperative flowmetric study in man.
        Scand J Thorac Cardiovasc Surg. 1972; 6: 140-148
        • Kalmanson D.
        • Veyrat C.
        • Chiche P.
        Atrial versus ventricular contribution in determining systolic venous return. A new approach to an old riddle.
        Cardiovasc Res. 1971; 5: 293-302
        • Benchimol A.
        • Desser K.
        • Gartlan J.
        Bidirectional blood flow velocity in the cardiac chambers and great vessels studied with the doppler ultrasonic flowmeter.
        Am J Med. 1972; 52: 467-473
        • Matsuo H.
        • Nimura Y.
        • Kitabatake A.
        • Hayashi T.
        Analysis of flow patterns in blood vessels with the directional ultrasonic doppler technique through a transcutaneous approach.
        Jpn Circ Res. 1973; 37: 735
        • Sivaciyan V.
        • Ranganathan N.
        Transcutaneous doppler jugular venous flow vedlocity recordings. Clinical and hmodynamic correlates.
        Circulation. 1978; 57: 930-939
        • Ranganathan N.
        • Sivaciyan V.
        Abnormalities in jugular venous flow velocity in pulmonary hypertension.
        Am J Cardiol. 1989; 63: 719-724
        • Ranganathan N.
        • Sivaciyan V.
        • Pryszlak M.
        • Freeman M.S.
        Changes in jugular venous flow velocity after coronary artery bypass grafting.
        Am J Cardiol. 1989; 63: 725-729
        • Shabetai R.
        • Fowler N.
        • Guntheroth W.
        The hemodynamics of cardiac tamponade and constrictive pericarditis.
        Am J Cardiol. 1970; 26: 480-489
        • Rittenhouse E.
        • Barnes R.
        Hemodynamics of cardiac tamponade : Early recognition from jugular vnous flow velocity.
        J Surg Res. 1975; 19: 35-41
        • Nelson R.
        • Jenson C.
        • Smoot W.
        Pericardial tamponande following open heart suregry.
        J Thoracic Cardiovasc Surg. 1969; 58: 510-516
        • Aloia Elio
        • Cameli Matteo
        • D'Ascenzi Flavio
        • Sciaccaluga Carlotta
        • Mondillo S.
        Tapse: An old but useful tool in different diseases.
        Int J Cardiol. 2016; 225: 7
        • Ghio S.R.
        • Klersy C.
        • Sebastiani M.
        • Laudisa M.L.
        • Campana C.
        • Tavazzi L.
        Prognostic usefulness of the tricuspid annular plane systolic excursion in patients with congestiove heart failure secondary to idiopathic or ischemic dilated cardiomyopathy.
        Am J Cardiol. 2000; 85: 6
        • Holt J.P.
        • Rhode E.A.
        • Kines H.
        Pericardial and ventricular pressure.
        Circ Res. 1960; 8: 1171-1181
        • Ranganathan N.
        • Sivaciyan V.
        Jugular venous flow velocity pattern application to bedside recognition of jugular venous pulse contour and right heart hemodynamics.
        American J of Noninvasive Cardiology. 1993; 7: 75-88
      7. Ranganathan N, Sivaciyan V, Saksena FB. The art and science of cardiac physical examination with heart sounds, jugular and precordial pulsations on cd includes 12-lead ecg interpretation. New Delhi,London, Philadelphia, Panama JAYPEE The Health Sciences Publisher; 2016.