Jugular Venous Inflow Velocity Patterns And The Relationship To The Right Atrial Pressure Pulse

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From the foregoing description of the RA pressure pulse, one can easily understand that the atrial pressure falls twice during each cardiac cycle: once during ventricular systole (x' descent) and once during ventricular diastole (y descent). The systolic descent in the presence of normal PR intervals is usually a combination of x and X descents, although the x' descent is more prominent and the important component. The fall during

Fig. 2. (A) Simultaneous recordings of right atrial (RA) pressure, superior vena caval flow velocity (SVC Fl) in a normal subject. Also shown are ECG, carotid pulse (CP), and phonocar-diogram (Phono) showing S2 for timing. All flow velocity recordings shown in this and all other figures are recorded in such a way that the velocities above the baseline zero (-0-) represent flows towards the right heart and all flow velocities below the baseline zero indicate flow direction away from the heart. The SVC flow is continuous and towards the heart and is biphasic with systolic flow velocity (Sf) > the diastolic flow velocity (Df). Sf corresponds to the X descent and the Df corresponds to the y descent in the RA pressure pulse. (Continued on next page.)

Fig. 2. (A) Simultaneous recordings of right atrial (RA) pressure, superior vena caval flow velocity (SVC Fl) in a normal subject. Also shown are ECG, carotid pulse (CP), and phonocar-diogram (Phono) showing S2 for timing. All flow velocity recordings shown in this and all other figures are recorded in such a way that the velocities above the baseline zero (-0-) represent flows towards the right heart and all flow velocities below the baseline zero indicate flow direction away from the heart. The SVC flow is continuous and towards the heart and is biphasic with systolic flow velocity (Sf) > the diastolic flow velocity (Df). Sf corresponds to the X descent and the Df corresponds to the y descent in the RA pressure pulse. (Continued on next page.)

x descent, which is caused by active ventricular systole, is more dominant than the fall during the y descent, which occurs during the comparatively "passive" atrial emptying in diastole when the tricuspid valve opens (across a small pressure gradient between the atrium and the ventricle). The venous return into the atrium is actually facilitated by the fall in the atrial pressure. In fact, acceleration in venous inflow velocity can be demonstrated whenever the atrial pressure falls during cardiac cycle (40).

Although the venous inflow in the jugulars is continuous, the jugular venous flow velocity, which is similar to flow velocity in the superior vena cava, in normal subjects is biphasic, with one peak in systole corresponding to the x' descent of the RA pressure pulse and a second peak in diastole corresponding to the y descent (allowing, however, for transmission delay) (Fig. 2A,B). The systolic flow (Sf) peak is normally more dominant compared to the diastolic flow (Df) peak, just as the x' descent is more dominant compared to the y descent in the normals (40). Venous inflow during atrial relaxation under normal conditions can only be seen on Doppler tracings ofjugular venous flow as a notch on the upstroke of the Sf velocity corresponding to the x descent; whereas the peak of the Sf always corresponds to the x' descent (Fig. 2C). Separate atrial relaxation flow as such can be demonstrated, however, during periods of A-V dissociation and when the PR interval is long (35,36,39,40).

The Sf and the corresponding x' descent may be somewhat diminished in atrial fibrillation. This is explainable because of the lack of atrial contraction in atrial fibrillation, which may lead to a decrease in Starling effect on the ventricle, thereby diminishing the dominance of the Sf as well as the corresponding x' descent (39,40,48) (Fig. 3).

Fig. 2. (Continued) (B) In the same normal patient similar simultaneous recordings are shown except instead of the superior vena caval (SVC) flow velocity recording, transcutaneous jugular venous flow (JVF) velocity is shown. The JVF, similar to the SVC flow, also has a biphasic flow pattern with the Sf velocity > the Df velocity. The peak of Sf in the JVF occurs somewhat later than that noted in the SVC Fl, almost at the time of the second heart sound (S2). The difference is because of the delay in transmission from the heart to the jugular. (C) Simultaneous recordings ofjugular venous flow (JVF), jugular venous pulse (JVP), ECG, and phonocardiogram (Phono) from a normal subject. Venous inflow during x descent representing the atrial relaxation is seen as a notch at the beginning of the systolic flow (Sf). Throughout the cardiac cycle the flow is always toward the heart (above the baseline zero). JVP contour in this normal patient shows a more prominent x' descent. (Modified from ref. 40 with permission from Lippincott Williams.)

Phono

Fig. 2. (Continued) (B) In the same normal patient similar simultaneous recordings are shown except instead of the superior vena caval (SVC) flow velocity recording, transcutaneous jugular venous flow (JVF) velocity is shown. The JVF, similar to the SVC flow, also has a biphasic flow pattern with the Sf velocity > the Df velocity. The peak of Sf in the JVF occurs somewhat later than that noted in the SVC Fl, almost at the time of the second heart sound (S2). The difference is because of the delay in transmission from the heart to the jugular. (C) Simultaneous recordings ofjugular venous flow (JVF), jugular venous pulse (JVP), ECG, and phonocardiogram (Phono) from a normal subject. Venous inflow during x descent representing the atrial relaxation is seen as a notch at the beginning of the systolic flow (Sf). Throughout the cardiac cycle the flow is always toward the heart (above the baseline zero). JVP contour in this normal patient shows a more prominent x' descent. (Modified from ref. 40 with permission from Lippincott Williams.)

The forward flow velocity patterns in the jugulars could, however, be altered and become abnormal secondary to alterations in the right heart function. It may then lose the dominance of the Sf (40,41,47). The relationship between the Sf and the Df velocity may be such that the Sf may be equal to the Df (Fig. 4). Sf may be less than the Df (Fig. 5), or it may become totally absent and may be replaced by a single Df(Fig. 6). These changes in jugular flow velocity patterns will, however, be accurately reflected by the corresponding changes in the RA pressure pulse contours of equal x' andy descents, x' descent less thany descent, or a single y descent (40,47).

Fig. 3. Simultaneous recordings of electrocardiogram (ECG), carotid pulse (CP), phonocardio-gram (Phono), and jugular venous flow (JVF) velocity in a patient with mitral regurgitation and atrial fibrillation. Because of lack of atrial contribution, the Starling effect is diminished leading to a decreased systolic flow. JVF shows a dominant diastolic flow (Df) compared to the less pronounced systolic flow (Sf).

Fig. 3. Simultaneous recordings of electrocardiogram (ECG), carotid pulse (CP), phonocardio-gram (Phono), and jugular venous flow (JVF) velocity in a patient with mitral regurgitation and atrial fibrillation. Because of lack of atrial contribution, the Starling effect is diminished leading to a decreased systolic flow. JVF shows a dominant diastolic flow (Df) compared to the less pronounced systolic flow (Sf).

Fig. 4. Simultaneous recordings of electrocardiogram (ECG), right atrial (RA) pressure, and superior vena cava (SVC) flow velocity from a patient with constrictive pericarditis. Note the variations from the normal. The RA pressure is high. The x' and y descents in the RA pressure tracing are equal, unlike the normal, and the corresponding SVC flow velocity shows a biphasic flow where the Sf and the Df are also equal.

Fig. 4. Simultaneous recordings of electrocardiogram (ECG), right atrial (RA) pressure, and superior vena cava (SVC) flow velocity from a patient with constrictive pericarditis. Note the variations from the normal. The RA pressure is high. The x' and y descents in the RA pressure tracing are equal, unlike the normal, and the corresponding SVC flow velocity shows a biphasic flow where the Sf and the Df are also equal.

ecg ecg

Fig. 5. Simultaneous recordings of electrocardiogram (ECG), right atrial (RA) pressure, and jugular venous flow (JVF) velocity from another patient with constrictive pericarditis. The y descent is more prominent, compared to the x' descent, on the RA pressure tracing. The corresponding JVF shows a more dominant Df compared to the Sf.

Fig. 5. Simultaneous recordings of electrocardiogram (ECG), right atrial (RA) pressure, and jugular venous flow (JVF) velocity from another patient with constrictive pericarditis. The y descent is more prominent, compared to the x' descent, on the RA pressure tracing. The corresponding JVF shows a more dominant Df compared to the Sf.

ecg ecg

Fig. 6. Simultaneous recordings of electrocardiogram (ECG), jugular venous pulse (JVP), and jugular venous flow (JVF) velocity from a patient with cardiomyopathy. The flow pattern is conspicuous for the absence of a systolic flow, and the JVP shows no x' descent. Instead, a single peak in diastole (Df) is seen. It corresponds to a single descent in the JVP also in diastole and therefore is the y descent. (See ECG for timing.) (Modified from ref. 40 with permission from Lippincott Williams and Wilkins.)

Fig. 6. Simultaneous recordings of electrocardiogram (ECG), jugular venous pulse (JVP), and jugular venous flow (JVF) velocity from a patient with cardiomyopathy. The flow pattern is conspicuous for the absence of a systolic flow, and the JVP shows no x' descent. Instead, a single peak in diastole (Df) is seen. It corresponds to a single descent in the JVP also in diastole and therefore is the y descent. (See ECG for timing.) (Modified from ref. 40 with permission from Lippincott Williams and Wilkins.)

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