Impact of preload changes on positive and negative left ventricular dP/dt and systolic time intervals: preload changes on left ventricular function

摘要

Aim/objectives: Previous work has shown that the electromechanical activation time (EMAT) is prolonged in patients with abnormally low left ventricular (LV) dP/dt. In the present study, we investigated whether EMAT was responsive to rapid changes in LV systolic function induced by abrupt increases in LV preload. Methods and results: A total of 116 patients were assessed before and after LV angiography with a bolus injection of 40 mL of non-ionic contrast dye. Left ventricular end-diastolic pressure (LVEDP) increased from 18+7mmHg to 20+-8mmHg (P<0.01). In patients with a baseline dP/dt<1500mmHg/sec, dP/dt increased from 1098+213 mmHg/sec to 1146+-306mmHg/sec (P=0.02) and EMAT decreased from 106+-29ms to 103+-18ms (P=0.02). In patients with a baseline dP/dt > 1500 mmHg/sec, dP/dt decreased from 1894+368 mmHg/sec to 1762 +-403 mmHg/sec (P=0.01) and EMAT increased from 88+-13 ms to 93 +- 16ms (P=0.02). Changes in negative dP/dt were similar to changes in dP/dt. Conclusion: Electromechanical activation time is a non-invasively measured parameter that allows accurate and rapid detection of changes in LV contractility.