Coronary flow reserve and diastolic dysfunction in hypertrophic cardiomyopathy

We studied 14 patients with hypertrophic cardiomyopathy during and after atrial pacing by simultaneous registration of left ventricular high fidelity pressure measurements and M-mode echocardiography together with great cardiac vein flow measured by thermodilution. Heart rate rose from 75 ± 18 to 142 ± 14 beats/minute with an increase of 93 ± 30 to 127 ± 46 milliliters/minute of great cardiac vein flow (increase 3f flow/beat: 0.8 versus 1.5 milliliters/beat in normal individuals; P < 0.05). In addition, diastolic hemodynamic parameters (such as left ventricular end-diastolic pressure, T₁ (time constant of relaxation) (of first 40 milliseconds) and T₂ (of second 40 milliseconds) and LVdP dt-) changed from, respectively, 27.4 ± 7.1 to 24.0 ± 10.3 mm Hg; (NS), 67.3 ± 16.1 to 65.7 ± 22.2 liters/second; (NS) 68.6 ± 36.9 to 52.9 ± 19.4 (P < 0.05), and 1592 ± 75 to 1302 ± 48 mm Hg/sec; P < 0.05. Left ventricular end-diastolic dimensions decreased whereas end-diastolic wall thickness increased from, respectively, 37 ± 3 to 34 ± 4 millimeters; (P < 0.05) and 14 ± 2 to 17 ± 1 millimeters (P < 0.05). Eleven of the 14 patients experienced angina pectoris concomitant with ST-T depression of 1 millimeter or more on the electro-cardiogram. No correlations were found between great cardiac venous flow and hemodynamically or ultrasonically derived diastolic parameters of left ventricular function.