Alterations of right ventricular systolic time intervals by chronic pressure and volume overloading.

Abstract

Right ventricular (RV) systolic time intervals and hemodynamic parameters were determined by micromanometric techniques in 13 subjects with normal right ventricles (NRV). These data were compared to those of 16 patients with pulmonary hypertension (PH) or predominant pressure overloading and 13 individuals with uncomplicated secundum atrial septal defects (ASD) or predominant volume overloading. In PH, the QP2 interval tends to remain within the normal range due to reciprocal changes in isovolumic contraction (ICT) and ejection (RVET) times. Elevations of pulmonary artery diastolic pressure are associated with increases in the mean rate of isovolumic pressure rise (MRIPR) (r = 0.84), but the latter change does not fully compensate for the widened ventriculoarterial diastolic pressure difference and ICT becomes prolonged (P less than 0.001). Factors other than stroke index depression which may contribute to the decreased duration of RVET (P less than 0.001) include tricuspid regurgitation and elevation of pulmonary vascular impedance. In ASD, QP2 is significantly prolonged (P less than 0.025) due to a significant increase in RVET (P less than 0.005). In contrast to NRV, a linear correlation of RVET and stroke index was not present, which suggested an alteration of ejection dynamics in this group. Despite a high incidence of complete or incomplete right bundle branch block the interval from QRS onset to rapid RV pressure upstroke was not prolonged. This is most probably the result of peripheral bundle branch block of genesis of the QRS pattern by right ventricular hypertrophy.

Accurate assessment of load-independent right ventricular systolic function in patients with pulmonary hypertension

“…where P iso is RV isovolumic pressure estimated by the single-beat method; mPAP is the mean pulmonary artery pressure taken as a surrogate of RV end-systolic pressure [21][22][23] ; and EDV, ESV and SV are RV end-diastolic, end-systolic and stroke volume, respectively.…”

Left and right ventricular systolic time intervals in the newborn. Usefulness and limitation in distinguishing respiratory disease from transposition of the great arteries.

“…A rise in the arterial diastolic pressure increases the time required for ventricular pressure to reach arterial pressure and to open the semilunar valve. Though this may, in part, be compensated for by a more rapid rate of rise of ventricular pressure, the net result is usually a prolongation of the pre-ejection period; additionally, arterial hypertension may shorten the ejection time (Curtiss et al, 1976). The result is that the ventricle facing systemic pressure tends to have a higher ratio of pre-ejection period to ejection time than does the ventricle facing pulmonary pressure.…”

“…Most studies have focused on tracing, and the phonocardiogram (Weissler et al, assessment of left ventricular performance, since 1969, 1972). There have been relatively few studies the left ventricular systolic time intervals can be of right ventricular systolic time intervals (Leighton et al, 1971;Curtiss et al, 1976), primarily because ' …”

“…Alterations of the systolic time intervals have been shown in patients with pulmonary hypertension (Hirschfeld et al, 1975b;Curtiss et al, 1976) and in patients with transposition of the great arteries (Hirschfeldet al, 1975a).…”

Right ventricular total isovolumic time: Reference value study

“…The evaluation of cardiac time intervals, since the introduction of the phonocardiogram to the validation of echocardiographic Doppler techniques, has always played a role in the comprehension of the cardiovascular pathophysiology …”