The left ventricle affects the duration of right ventricular ejection.

OBJECTIVE

The aim was to determine if rapid changes in left ventricular pressure can acutely alter right ventricular systolic pressure and thus influence the length of right ventricular ejection.

METHODS

The experiments were performed in six open chest anaesthetised dogs, weight 18-25.5 kg. Left and right ventricular pressures and pulmonary blood flow were recorded continuously as left ventricular pressure was abruptly decreased by opening a shunt in systole. From these data, the pressure and flow changes and the duration of right ventricular ejection were determined.

RESULTS

Opening the left ventricular shunt caused left ventricular pressure to fall from 94.1(SD 10.5) to 62.6(11.3) mm Hg (p < 0.01), right ventricular pressure to fall from 30.3(4.6) to 27.0(3.6) mm Hg (p < 0.01), and pulmonary flow to fall from 69.5(14.2) to 57.5(13.9) ml.s-1. The duration of right ventricular ejection, determined from pulmonary flow, also decreased from 192.7(22.7) to 157.2(18.7) ms (p < 0.05) and was significantly related to the length of left ventricular systole. Time between end diastole and peak negative dP/dt decreased for both left and right ventricle. Left and right ventricular time intervals were related before (r = 0.99) and after (r = 0.75) opening the shunt.

CONCLUSIONS

The duration of right ventricular ejection was decreased by a sudden decrease in left ventricular afterload and was significantly related to the length of left ventricular systole. The duration of right ventricular ejection may be coupled with left ventricular contraction through ventricular interdependence.