Tetsuo Okamura

Correlation of common carotid flow volume measured by ultrasonic quantitative flowmeter with pathological findings.

To evaluate the possibility of quantitatively diagnosing carotid and cerebral atherosclerosis noninvasively, we measured common carotid flow volume in 60 sides (30 patients), using an ultrasonic quantitative flowmeter, and then compared these findings to the severity score of carotid and cerebral atherosclerosis as determined at autopsy. Stenosis decreased common carotid flow volume in the carotid and cerebral arteries. Increases in the severity score varied inversely with reduced flow volume, which was high in inverse correlation (r = -0.696). Patients with flow volumes of 8.5 ml/sec or greater did not have stenosis greater than or equal to 75%, whereas all patients with flow volumes of 6.4 ml/sec or less had stenosis greater than or equal to 50%, with 45% of these having stenosis greater than or equal to 75%. These pathological findings confirm that the common carotid flow volume reflects the degree of carotid and cerebral atherosclerosis present and that the lower limit of common carotid flow volume in healthy subjects is 6.5 ml/sec.

STUDY ON THE GENESIS OF THE DOUBLE POTENTIAL RECORDED IN THE HIGH RIGHT ATRIUM IN ATRIAL FLUTTER AND ITS ROLE IN THE REENTRY CIRCUIT OF ATRIAL FLUTTER

To investigate the genesis of the double potential (DP), which is two separate waves, and its role in the reentry circuit of atrial flutter (AF), we performed overdrive pacing (ODP) from the high right atrium (HRA) in six cases of spontaneous AF in which the DP was recorded in the HRA. In four of the six cases, when the DP was arbitrarily designated D1 and D2, D1 and D2 showed progressive fusion during ODP. In addition, the D1 return cycle, immediately after the termination of ODP, corresponded to the AF cycle, and the D2 return cycle corresponded to the pacing cycle. This may indicate that the DP is caused by the collision of two directional waves. Furthermore, it is suggested that the HRA plays an important role in preventing a possible shortcutting of reentry waves and in stabilizing the reentry circuit of AF.

Secondary Flow and Atherogenesis

Hemodynamic factors appear to affect atherosclerosis. Secondary flow in the aorta was studied by subjecting rabbits to constant pressure perfusion fixation and observing endothelial arrangement by scanning electron microscopy.

The effect of beta-adrenergic blockade in dilated cardiomyopathy--a questionnaire study in Japan.

SummaryThe effect of beta-blockade in dilated cardiomyopathy was studied by a questionnaire survey. Thirty-three cases were monitored in whom metoprolol (22 patients, 35.9 ± 20.4 mg, mean ± SD), propranolol (four patients, 26.3 ± 7.5 mg), or other beta-blockers (seven patients) were administered. Four patients died, but no direct relationship was found between administration of beta-blocker and death. The NYHA functional class improved significantly. The mean heart rate decreased from 96/min to 77/min (P < 0.01). The mean cardiothoracic ratio decreased from 55.6% to 52.1% (P < 0.01). The mean ejection fraction of the left ventricle measured by echocardiogram increased from 30.4% to 36.9% (P < 0.01). Exercise tolerance in the treadmill test improved significantly. There was no change in blood pressure, nor were there arrhythmias seen on Holter electrocardiograms. In two patients, congestive heart failure deteriorated after administration of beta-blockers. It is concluded that beta-adrenergic blockade has a beneficial effect in most of the patients with dilated cardiomyopathy.