Elevated Venous Pressure

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The most common cause of an elevated jugular venous pressure is an increased RV pressure such as occurs in patients with pulmonic stenosis, pulmonary hypertension, or RV failure secondary to left-sided heart failure or RV infarction. The venous pressure also is elevated when obstruction to RV inflow occurs, as with tricuspid stenosis or RA myxoma, or when constrictive pericardial disease impedes RV inflow. It also may result from vena cava obstruction and, at times, an increased blood volume. Patients with obstructive pulmonary disease may have an elevated venous pressure only during expiration.

KUSSMAUL'S SIGN

Normally, during inspiration, there is an increase in the a wave of the JVP but a decrease in the mean jugular venous pressure as a result of the increased filling of the right-sided chambers associated with the decrease in intrathoracic pressure. Kussmaul's sign denotes an inspiratory increase in the venous pressure, which may occur in patients with severe constrictive pericarditis when the heart is unable to accept the increase in RV volume without a marked increase in the filling pressure. Although Kussmaul's sign was first described in patients with constrictive pericarditis, its most common cause is severe right-sided heart failure, regardless of etiology. The presence of Kussmaul's sign is also useful in the diagnosis of RV infarction204 (see Chap. 72).

ABNORMALITIES OF THE a WAVE

The a wave in the JVP is absent when there is no effective atrial contraction, such as in atrial fibrillation (see 0+;S; Fig. 10-45.fi). In certain other conditions, the a wave may not be apparent. In sinus tachycardia, the a wave may fuse with the preceding v wave, particularly if the PR interval is prolonged. In some patients with sinus tachycardia, the jugular a wave may occur during the v or y descent and may be small or absent. In the presence of first-degree AV block, a discrete a wave with ascending and descending limbs is often completed prior to the first heart sound, and the ac interval is prolonged (see B+iSi Fig. 10-45.fi).

Large a waves are of considerable diagnostic value (see B-hB; Fig. 10-45.fi). When giant a waves are present with each beat, the right atrium is contracting against an increased resistance. This may result from obstruction at the tricuspid valve (tricuspid stenosis or atresia, right atrial myxoma) or conditions associated with increased resistance to RV filling.200 A giant a wave is more likely to occur in patients with pulmonic stenosis or pulmonary hypertension in whom both the atrial and ventricular septa are intact.

Cannon a waves occur when the right atrium contracts while the tricuspid valve is closed during RV systole.200 Cannon a waves may occur either regularly or irregularly and are most common in the presence of arrhythmias (see B+sB; Fig. 10-456*).

ABNORMALITIES OF THE x WAVE

The most important alteration of the normally negative systolic collapse (x wave) of the JVP is its obliteration or even replacement by a positive wave. This is usually due to tricuspid regurgitation. Although atrial relaxation may contribute to the normal x descent, the development of atrial fibrillation does not obliterate the x wave except in the presence of tricuspid regurgitation. Accordingly, the occurrence of a positive wave in the JVP during ventricular systole is strong evidence of tricuspid regurgitation (Fig. 10-46^). Mild tricuspid regurgitation lessens and shortens the downward x wave as the regurgitation of blood into the right atrium produces a positive wave that diminishes the usual systolic fall in venous pressure. In some patients with moderate tricuspid regurgitation, there is a fairly distinct positive wave during ventricular systole between the c and v waves. This abnormal systolic waveform is usually referred to as a v or cv wave, although it has also been referred to as an r (regurgitant) or an s (systolic) wave. In patients with constrictive pericarditis, the x descent wave during systole is often more prominent than the early diastolic y wave (see B-H0i Fig. 10-45 C and Chap. 72).

Ecg Waveform For Tricuspid Atresia

Figure 10-46: Right ventricular (RV) and right atrial (RA) pressure curves and simultaneous ECG from a patient with severe tricuspid regurgitation. Note ventricularization of the RA pressure curve.

Figure 10-46: Right ventricular (RV) and right atrial (RA) pressure curves and simultaneous ECG from a patient with severe tricuspid regurgitation. Note ventricularization of the RA pressure curve.

ABNORMALITIES OF THE v WAVE

The positive, late systolic v wave results from the increasing RA blood volume during ventricular systole when the tricuspid valve normally is closed. With mild tricuspid regurgitation, the v wave and the obliteration of the x descent result in a single, large positive systolic wave (ventricularization) (see Figs. 10-45/1 and 10-46).

Normally in the JVP the v wave is lower in amplitude than the a wave. In patients with an ASD, however, the a and v waves are often equal in the right atrium and the JVP (see Fig. 10-46.). In patients with constrictive pericarditis and sinus rhythm, the RA a and v waves also may be equal, but the venous pressure is increased, which is unusual with isolated ASD. In patients with constrictive pericarditis who are in atrial fibrillation, the cv wave is prominent and the y descent rapid.

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Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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  • asmait
    What does an elevated pressure in a coronary valve mean?
    7 years ago

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