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Phasic coronary flow characteristics in patients with hypertrophic cardiomyopathy: a study by coronary Doppler
T Akasaka1, J Yoshikawa, K Yoshida
1Department of Cardiology, Kobe General Hospital, Japan.
Insights
Patients with hypertrophic cardiomyopathy exhibit systolic flow reversal and altered diastolic coronary flow patterns. These abnormal coronary flow velocity characteristics correlate with left ventricular asymmetry and septal artery narrowing.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Medical Imaging
Background:
- Abnormal coronary flow velocity patterns are known in symmetric left ventricular hypertrophy (LVH).
- Phasic coronary flow characteristics in asymmetric LVH, specifically hypertrophic cardiomyopathy (HCM), remain understudied.
Purpose of the Study:
- To assess phasic coronary flow characteristics in patients with hypertrophic cardiomyopathy.
- To investigate the relationship between coronary flow parameters and echocardiographic/hemodynamic data in HCM.
Main Methods:
- Coronary flow velocity was measured using a 20 MHz Doppler catheter in the left anterior descending artery.
- Eight patients with hypertrophic nonobstructive cardiomyopathy and eight control subjects were studied.
Main Results:
- Patients with HCM showed systolic flow reversal and significantly smaller systolic flow integrals compared to controls.
- HCM patients exhibited prolonged diastolic initiation time and shorter diastolic deceleration time.
- Coronary flow abnormalities correlated significantly with ventricular septal thickness, septal/free wall ratio, and septal artery narrowing.
Conclusions:
- Systolic flow reversal and altered diastolic flow (slow acceleration, rapid deceleration) are characteristic of HCM.
- These flow abnormalities may be linked to left ventricular asymmetry and compression of septal perforator arteries.
Abstract:
Abnormal patterns of coronary flow velocity have been observed in patients with symmetric left ventricular hypertrophy in conditions such as aortic stenosis and systemic hypertension. However, phasic coronary flow characteristics have not been investigated in patients with asymmetric left ventricular hypertrophy in hypertrophic cardiomyopathy. The purpose of this study was to assess phasic coronary flow characteristics and their relation to echocardiographic and hemodynamic parameters in patients with hypertrophic cardiomyopathy. Coronary flow velocity was recorded in the left anterior descending artery with a 20 MHz Doppler catheter in eight patients with hypertrophic nonobstructive cardiomyopathy and eight control subjects with normal coronary arteries. Flow reversals observed in systole in all patients with hypertrophic cardiomyopathy, and the time velocity integrals of systolic flow were significantly smaller in patients with hypertrophic cardiomyopathy than in control subjects (-1.5 +/- 1.7 versus 4.3 +/- 1.2 cm; p < 0.01). The time from the beginning of diastole to peak diastolic velocity corrected by the square root of R-R interval (square root of RR) was prolonged significantly, and the velocity half-time from peak diastolic velocity corrected by square root of RR was shorter in the patients with hypertrophic cardiomyopathy compared with those in the control subjects (6.8 +/- 2.0 msec versus 4.0 +/- 0.6 msec [p < 0.01] and 9.2 +/- 4.9 msec versus 13.9 +/- 2.0 msec [p < 0.05], respectively). Peak velocity and time velocity integral of flow reversal showed significant correlations with anterior ventricular septal thickness (y = -0.5x + 13.5, r = 0.8, and p < 0.01; y = -1.3 +/- 16.8, r = 0.8, and p = 0.024, respectively), the septal/free wall thickness ratio (y = -0.1x + 1.1, r = 0.8, and p < 0.01; y = -0.2x + 1.4, r = 0.9, and p < 0.01, respectively), and the degree of narrowing of the first septal perforator arteries (y = 1.9x + 91.6, r = 0.8, and p = 0.012; y = 6.1x + 80.6, r = 0.9, and p < 0.01, respectively). In conclusion, flow reversal in systole and slow acceleration and rapid deceleration in diastole were characteristics in patients with hypertrophic cardiomyopathy. Flow reversal might be related to the degree of left ventricular asymmetry and compression of the septal perforator arteries.