What do we gain from the analysis of right ventricular function?

Right ventricular filling in dilated cardiomyopathy

PURPOSE

To assess right ventricular filling in dilated cardiomyopathy.

PATIENTS

32 patients with dilated cardiomyopathy and 24 healthy controls.

METHODS

Stroke distances were measured by pulsed Doppler echocardiography at left ventricular outflow and left and right ventricular inflow. The inflow tract dimensions of both ventricles and the outflow tract dimension of the left ventricle were measured from two dimensional images. Right and left sided atrioventricular (AV) ring excursions were measured by M mode echocardiography at the tricuspid and mitral rings. Stroke volume was derived as stroke distance multiplied by left ventricular outflow tract area. Total stroke distances were calculated as the sum of AV valve Doppler stroke distances and ring excursion. The effective orifice areas of the two AV valves were thus defined as stroke volumes divided by total stroke distance.

RESULTS

Total tricuspid stroke distance was normally less than mitral (6.0 (1.7) v 7.6 (1.7) cm, P < 0.05), implying that effective orifice area of the tricuspid valve was consistently greater (6.6 (1.6) v 4.5 (0.8) cm2, P < 0.01). Total tricuspid ring excursion was normally more than mitral (2.30 (0.30) v 1.62 (0.22) cm, P < 0.01). Total tricuspid stroke distance in dilated cardiomyopathy was also less than mitral (7.8 (2.4) v 9.7 (2.8) cm, P < 0.05). Tricuspid stroke distance was significantly increased in patients with dilated cardiomyopathy compared with that in healthy controls (P < 0.05 v controls), though stroke volume was much smaller (26 (10) v 63 (11) ml, P < 0.01) so that tricuspid effective orifice area was reduced to less than half normal (2.7 (1.2) cm2, P < 0.01). Total tricuspid ring long axis excursion was more than mitral (1.37 (0.6) v 0.74 (0.21) cm, P < 0.01). Right ventricular end diastolic inflow dimension was increased compared with that in healthy controls (3.9 (0.7) v 2.8 (0.5) cm, P < 0.01), correlating inversely with tricuspid effective orifice area (r = -0.71, P < 0.01). Total tricuspid ring excursion was bimodally distributed as a low amplitude group (less than 1.6 cm, n = 23) and a high amplitude group (more than 1.6 cm, n = 9), in which the interval P2 to onset of tricuspid flow was much longer (100 (35) v 50 (14) ms, P < 0.01).

CONCLUSIONS

Enlargement of the right ventricular inflow tract in dilated cardiomyopathy, especially to more than 5 cm, is accompanied by a progressive decrease in effective tricuspid orifice area, sometimes to less than 1 cm2 and increased inflow velocities. Right ventricular relaxation was incoordinate in 28% of the patients studied. These disturbances of right ventricular filling are likely to compromise overall cardiac function independently of left ventricular disease.

Pulsed Doppler assessment of tricuspid regurgitation: usefulness of regurgitant signal patterns for estimation of severity

A study on the value of pulsed Doppler in the detection and quantitative assessment of tricuspid regurgitation (TR) has been conducted on 33 consecutive adult patients with valvular heart disease. Only 1 patient had to be excluded owing to a technically inadequate Doppler examination. Data for comparison were obtained from a right heart catheterization performed within a twenty-four-hour interval from the Doppler study. Sensitivity and specificity in the detection of the lesion were 88% and 100%, respectively. A previously undescribed pulsed Doppler method for the estimation of the degree of TR was tested, based on the consideration of two distinctive patterns of the regurgitant Doppler signal: type I: a protosystolic regurgitant signal with progressively fading intensity along systole; and type II: a homogeneously intense pansystolic signal. Correlation between these patterns and the angiographic degrees of TR showed that milder lesions correspond to the type I Doppler pattern, whereas significant regurgitations present a type II pattern, this allowing a clinically useful method of assessment of TR.

Echocardiographic measurement of the normal adult right ventricle

In studies of the right ventricle the complexities of chamber shape may be overcome by use of multiple tomographic imaging planes. An established protocol for the echocardiographic description of the heart was used to examine the right ventricle in an ordered series of transducer locations and orientations. Diastolic measurements were made of the right ventricular inflow tract, outflow tract, and right ventricular body, and the range and reproducibility of normal values for cavity size and right ventricular free wall thickness were established. These measurements of cavity size in 41 normal subjects were highly reproducible and the views that were used correctly described the truncated and ellipsoidal shape of the right ventricular inflow tract and body with a separately aligned outflow tract. Cavity trabeculation prevented measurement of the free wall thickness in some areas; however, values of nearly twice the previously reported upper limit of normal for anterior regions were measured from the apex or lateral right ventricular wall. These normal data provide a basis for future echocardiographic studies of the right ventricle.

Right ventricular function in patients with chronic obstructive pulmonary disease

Simultaneous right heart catheterization and radionuclide ventriculography were performed in 27 patients with a wide range of chronic obstructive pulmonary disease. Central hemodynamics and radionuclide studies were done at rest and during exercise. In the resting state the right ventricular ejection fraction (RVEF) was in the normal range (43.3 +/- 6%). During exercise a significant (p less than 0.001) decrease of RVEF to 38.8 +/- 6.7% occurred. The pulmonary artery mean pressures were 19.9 +/- 3.8 at rest. During exercise a significant (p less than 0.001) increase to 41 +/- 9.8 mm Hg occurred. There was a linear relationship between pulmonary pressures and RVEF during exercise in patients with pulmonary artery pressures not exceeding 35 mm Hg. In patients with right ventricular end-diastolic wall thickness greater than or equal to 6 mm a curvilinear relationship between these parameters could be observed with a flattening of the curve at higher pressures (greater than 35 mm Hg) and lower ejection fractions (less than 35% RVEF). Radionuclide ventriculography cannot substitute for right heart catheterization. Echocardiography is useful for interpretation of right ventricular ejection fractions in advanced chronic obstructive pulmonary disease.