CHANGE OF LEFT ATRIAL SYSTOLIC PRESSURE WAVE-FORM IN RELATION TO LEFT-VENTRICULAR END-DIASTOLIC PRESSURE

The relation between the left atrial systolic pressure waveform and left ventricular end-diastolic pressure was observed in 17 patients who underwent diagnostic cardiac catheterization. Left atrial pressure and left ventricular pressure were simultaneously recorded from a multisensor catheter before and during angiotensin infusion. Left ventricular systolic pressure and left ventricular end-diastolic pressure were 133±17 and 12.3±3.2 mm Hg, respectively, before angiotensin infusion and increased to 168±18 (p<0.01) and 19.4±4.5 mm Hg (p<0.01), respectively, during infusion. The left atrial systolic pressure curve consisted of two positive waves - a first wave (A) and a second wave (A′). The A and A′ wave pressures were 11.6±2.3 and 10.2±3.9 mm Hg, respectively, before angiotensin infusion and 16.5±2.9 (p<0.01) and 18.1±4.7 mm Hg (p<0.01), respectively, during infusion. The ratio of A′/A of left atrial systolic pressure was 0.81±0.27 before angiotensin infusion and 1.08±0.14 (p<0.01) during infusion. The ratio of A′ to A of left atrial systolic pressure was linearly related to left ventricular end-diastolic pressure before and during (p<0.01) angiotensin infusion. The amplitude of the A wave exceeded that of the A′ wave at normal left ventricular end-diastolic pressures. However, as the left ventricular end-diastolic pressure increased either at rest or during angiotensin infusion, the amplitude of the A′ wave increased and often exceeded that of the A wave. These results suggest that the second (A′) wave might be attributed to the increased reflection associated with increased left ventricular end-diastolic pressure.