Key result
Phonocardiographic mid-ejection time correlates with heart rate and QRS width but not LV function.
Why the study?
Does phonocardiographically measured mid-ejection time correlate with myocardial contractility in patients with prosthetic aortic valves?
Observational (n=42)
Does phonocardiographically measured mid-ejection time correlate with myocardial contractility in patients with prosthetic aortic valves?
Phonocardiographically measured mid-ejection time correlates with heart rate and QRS width but not with other left ventricular function estimates, suggesting ventricular asynchrony may invalidate contractile element velocity assessments in abnormal myocardium.
Mid-ejection time may not reflect contractility in prosthetic valve patients; leaves open its validity amid ventricular asynchrony effects.
The phonocardiographically recorded time interval between the first heart sound and the mid-ejection point is a rough guide to the time interval between the onset and the peak ventricular pressure in patients with the University of Cape Town aortic valve prosthesis. This time interval is insensitive to changes in stroke volume and aortic pressure produced by variations in ventricular filling and may be used to show changes in contractility in any one patient. In a group of 42 patients with 64 postoperative phonocardiograms, mid-ejection time varied between 140 and 250 msec. A strong negative correlation with heart rate, and a strong positive correlation with the width of the QRS complex were present without any significant correlation with heart size or with other estimates of left ventricular function. It is suggested that in the abnormal myocardium, ventricular asynchrony may seriously interfere with the velocity of the ventricular contraction invalidating the assessment of contractile element velocity from the velocity components of the ventricular pressure pulse.
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Beck et al. (1968) conducted an observational in Prosthetic Aortic Valves (n=42). Phonocardiographically measured time components of ventricular contraction was evaluated on Correlation of mid-ejection time with heart rate, QRS width, heart size, and left ventricular function. Phonocardiographically measured mid-ejection time (140-250 msec) showed strong correlations with heart rate and QRS width, but not with heart size or other estimates of left ventricular function.
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