ABSTRACT
The left ventricular regional systolic functions in patients with hypertrophic cardiomyopathy (HCM) were assessed by using quantitative tissue velocity imaging (QTVI). Left ventricular (LV) regional myocardial velocity along long- and short-axis in 31 HCM patients and 20 healthy subjects were analyzed by QTVI, and the regional myocardial systolic peak velocities (MVS) were measured. Mean MVS at each level including mitral annular, basal, middle and apical segments were calculated. The ratio of MVS along long-axis to that along short-axis (Ri) at basal and middle segments of the LV posterior wall and ventricular septum were calculated. The results showed that mean MVS was slower at each level including mitral annular, basal, middle and apical segments in the HCM patients than that in the healthy subjects (P＜0.01). There were no significant differences in mean MVS between obstructive and non-obstructive groups in HCM patients. MVS of all regional myocardial segments along long-axis in the HCM patients were significantly slower than that in the healthy subjects (P＜0. 05), but there was no significant difference in MVS of all regional myocardial segments along long-axis between hypertrophied and non-hypertrophied group in the HCM patients. Ri was significantly lower in the HCM patients than that in the healthy subjects. The LV regional myocardial contractility along long-axis was impaired not only in the hypertrophied wall but also in the non-hypertrophied one in patients with HCM, suggesting that QTVI can assess accurately LV regional systolic function in patient with HCM and provides a novel means for an early diagnosis before and independent of hypertrophy.
ABSTRACT
In order to observe the changes in left ventricular function during coronary artery occlusion and reperfusion, left anterior descending (LAD) coronary arteries in the anesthetized dogs were occluded for 1 hour and then reperfused for 4 hours. Hemodynamic indexes of global systolic and diastolic function and regional wall thickness changes as a regional contractile index were measured during occlusion and reperfusion. The results were as follows; 1) Indexes of global systolic function (left ventricular peak systolic pressure, peak positive dP/dt) and global diastolic function (peak negative dP/dt, time constant, left ventricular end-diastolic pressure) showed deterioration in early occlusion period (10-30 minutes) but gradually improved even if coronary occlusion persisted. Reperfusion did not induce significant changes except that peak positive dP/dt transiently deteriorated 30 minutes after reperfusion and left ventricular end-diastolic pressure decreased 1.5-2 hours after reperfusion. 2) Indexed of regional function (i.e, end-diastolic thickness and % systolic thickening of anterior left ventricular wall) deteriorated by 10 minutes' occlusion which persisted during the entire occlusion period. Reperfusion induced no significant improvement in regional contractile function compared with occlusion 60 minutes' data, which suggested reperfusion for 4 hours after 1 hour's LAD occlusion may be insufficient for the ischemic region to recover its contractility. 3) Reperfusion arrhythmia (ventricular tachycardia) was noted in most (6/9) of the dogs, one of which deteriorated into ventricular fibrillation and the others spontaneously converted to normal sinus rhythm.