Key result
The transcutaneous Doppler index (ΔECG Q-Doppler peak) significantly differentiated patients with coronary artery disease (9 ± 25 msec) from normal subjects (-32 ± 26 msec, p<0.001), showing less overlap than systolic time intervals.
Why the study?
Does transcutaneous measurement of delta ECG Q-Doppler peak accurately reflect myocardial contractility and differentiate patients with coronary artery disease from normal subjects?
Observational (n=74)
Yes
Does transcutaneous measurement of delta ECG Q-Doppler peak accurately reflect myocardial contractility and differentiate patients with coronary artery disease from normal subjects?
Absolute Event Rate: 9% vs -32%
p-value: p=<0.001
Transcutaneous measurement of the ECG Q-Doppler peak from the carotid artery provides a useful, noninvasive index of myocardial contractility that can help differentiate normal subjects from those with coronary artery disease.
May support noninvasive CAD differentiation; leaves open prospective validation before clinical use.
An attempt was made to derive a useful noninvasive index to evalute a change in myocardial contractile state using transcutaneous Doppler flow-velocity curve from the carotid artery. In 5 mongrel dogs and in 43 patients with various heart disease, Doppler flow velocity curves were obtained from the ascending aorta intravascularly using a Doppler catheter and/or from carotid artery transcutaneously using a Doppler probe. The first derivative of left ventricular pressure (dp/dt) and electrocardiogram (ECG) were recorded simultaneously. The following 3 indices were measured from the Doppler flow-velocity curves: (1) macimum acceleration of blood flow (dv/dt), (2) time from onset of ejection to peak flow (time-to-peak), (3) time interval between the beginning of Q wave of ECG to the peak of Doppler flow velocity curve (ECG Q-Doppler peak). Among these 3 indices, only ECG Q-Doppler peak demonstrated a significant correlation between the values measured intravascularly and transcutaneously. Also, only ECG Q-Doppler peak showed significant correlation with maximum of dp/dt (max dp/dt). Since ECG Q-Doppler peak showed correlation with heart rate, the difference between observed and predicted ECG Q-Doppler peak (delta ECG Q-Doppler peak) was calculated to exclude the effect of heart rate. Predicted value of ECG Q-Doppler peak was calculated from the regression equation between heart rate and ECG Q-Doppler peak in the separate experiments. There was significant correlation between delta ECG Q-Doppler peak and max dp/dt. In 15 patients with coronary artery disease and in 16 healthy subjects, delta ECG Q-Doppler peak and the other noninvasive method (systolic time intervals) were measured. Delta ECG Q-Doppler peak showed better result in the separation of 2 groups than by systolic timeintervals. It was concluded that delta ECG Q-Doppler peak is a useful index to evaluate the myocardial contractile state since this index is readily obtained noninvasively.
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Ishikawa et al. (1975) conducted an observational in Coronary artery disease and various heart diseases (n=74). Transcutaneous Doppler flow-velocity curve measurement (ΔECG Q-Doppler peak) vs. Systolic time intervals and normal subjects was evaluated on Difference in ΔECG Q-Doppler peak between patients with coronary artery disease and normal subjects (p=<0.001). The transcutaneous Doppler index (ΔECG Q-Doppler peak) significantly differentiated patients with coronary artery disease (9 ± 25 msec) from normal subjects (-32 ± 26 msec, p<0.001), showing less overlap than systolic time intervals.
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