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Hemodynamic benefit of atrioventricular synchrony: prediction from baseline Doppler-echocardiographic variables
A C Pearson1, D L Janosik, R M Redd
1Department of Internal Medicine, St. Louis University Medical Center, Missouri.
Insights
Baseline stroke volume, not diastolic function, predicts hemodynamic benefits from atrioventricular synchronous pacing. Lower VVI stroke volume indicates greater cardiac output increase with AV synchronous pacing.
Area of Science:
- Cardiology
- Biomedical Engineering
- Echocardiography
Background:
- Atrioventricular (AV) synchronous pacing aims to optimize cardiac function.
- Predicting the hemodynamic benefit of AV synchronous pacing is crucial for patient management.
Purpose of the Study:
- To assess if baseline echocardiographic parameters of systolic or diastolic function can predict the hemodynamic benefits of AV synchronous pacing.
Main Methods:
- Twenty-four patients with dual-chamber pacemakers were studied.
- Echocardiography (M-mode, 2D, Doppler) assessed cardiac function in VVI, VDD, and DVI pacing modes.
- Cardiac output and stroke volume were measured at various AV intervals.
Main Results:
- Baseline Doppler-echocardiographic variables of systolic or diastolic function did not correlate with increased cardiac output during AV synchronous pacing.
- Stroke volume in VVI mode significantly correlated with the percent increase in cardiac output during physiologic pacing (VDD and DVI modes).
- Patients with VVI stroke volume < 50 ml were more likely to have ventriculoatrial (VA) conduction.
Conclusions:
- Baseline stroke volume in single-rate demand pacing (VVI mode) is a predictor of hemodynamic improvement with AV synchronous pacing.
- Echocardiographic measures of systolic and diastolic function at baseline do not reliably predict the benefits of AV synchronous pacing.
Abstract:
The purpose of this study was to determine if baseline Doppler-echocardiographic variables of systolic or diastolic function could predict the hemodynamic benefit of atrioventricular (AV) synchronous pacing. Twenty-four patients with a dual chamber pacemaker were studied. Baseline M-mode and two-dimensional echocardiograms were obtained and Doppler-echocardiographic measurements of mitral inflow and left ventricular outflow were made in VVI mode (single rate demand) and in VDD (atrial synchronous, ventricular inhibited) and DVI (AV sequentially paced) modes at AV intervals ranging from 50 to 300 ms. Forward stroke volume and cardiac output were determined in each mode at each AV interval from the left ventricular outflow tract flow velocities, and the percent increase in cardiac output over VVI mode was determined. M-mode measurements, including left ventricular end-diastolic dimension, shortening fraction and left atrial size and Doppler measurement of diastolic filling, including peak early velocity and percent atrial contribution, did not correlate with the percent increase in cardiac output during physiologic pacing. The stroke volume in VVI mode correlated significantly with the percent increase in cardiac output during physiologic pacing (r = -0.61, p less than 0.005 for VDD mode and r = -0.55, p less than 0.05 for DVI mode). Five of the 15 patients with VVI stroke volume less than 50 ml but none of the 9 patients with stroke volume greater than 50 ml had ventriculoatrial (VA) conduction.(ABSTRACT TRUNCATED AT 250 WORDS)