Effect of trimetazidine on 99Tcm-tetrofosmin uptake in patients with coronary artery disease.

Myocardial uptake of 99Tcm-tetrofosmin in vivo is determined by a combination of flow and metabolic status of myocytes. The accumulation of tetrofosmin in the mitochondria is related to their ability to transduce metabolic energy into electronegative membrane potential. Trimetazidine (TMZ), an anti-ischaemic drug, appears to have a metabolic cytoprotective effect related to mitochondrial function, since it does not induce systemic or coronary haemodynamic changes. In this study, we evaluated the effects of TMZ on tetrofosmin uptake in hypoperfused myocardial regions in patients with coronary artery disease (CAD). Twenty-two patients, 14 with previous myocardial infarction (group A) and eight with a history of angina (group B), with angiographically documented CAD were studied. All patients underwent two tetrofosmin SPET studies at rest, before (baseline) and 1 week after TMZ administration (post-TMZ). On quantitative analysis, 131 segments showed less tetrofosmin uptake at baseline. In these segments, tetrofosmin uptake was 51 +/- 13% at baseline and 55 +/- 15% post-TMZ (P < 0.001 vs control). In the 86 hypoperfused segments of group A, tetrofosmin uptake was 48 +/- 14% at baseline and 52 +/- 17% post-TMZ (P < 0.001 vs control). In the 45 hypoperfused segments of group B, tetrofosmin uptake was 56 +/- 9% at baseline and 60 +/- 10% post-TMZ (P < 0.001 vs control). In the remaining 309 segments, no significant difference in tetrofosmin uptake before and after TMZ was observed. In conclusion, our results suggest that TMZ administration may increase myocardial uptake of tetrofosmin in hypoperfused regions at rest in patients with CAD, based on its metabolic effect.

Left ventricular function and exercise tolerance in patients with type II diabetes mellitus.

BACKGROUND: Left ventricular (LV) preload changes may alter exercise tolerance (ET), probably lessening activation of the Maestrini-Starling mechanism. Reduced LV filling (pre-load) during the diastolic phase, usually impaired in diabetic patients, could affect ventricular function. HYPOTHESIS: To evaluate the relationship between some echocardiographic LV function indices and ET, 24 patients (age 43-75 years, mean 54 +/- 13 years, Group A) with type II diabetes mellitus (DM), not suffering from other pathologies, and for whom the ergometric stress test (EST) resulted in an early interruption because of muscular fatigue and/or dyspnea, and 14 patients (age 38-70 years, mean 53 +/- 12 years, Group B) with type II DM and maximal ergometric stress test, used as control group, were studied. METHODS: The EST was performed by increasing the load by 25 W every 2 min; its duration was used as an ET index and correlated with clinical parameters of LV function obtained with M-mode, two-dimensional, and Doppler echocardiography. RESULTS: No patients in either Group A or Group B showed a high systolic blood pressure value at rest and/or an LV hypertrophy and/or an alteration of systolic functional indices. In neither group was there significant correlation between ET and duration of DM, basal heart rate, basal and max systolic blood pressure, and EF values. Linear regression analysis showed a significant correlation between Doppler parameters of the diastolic function and ET index in Group A, while there was no significant correlation in Group B. CONCLUSION: From these data we can deduce that in absence of left systolic ventricular dysfunction the impairment of LV relaxation in DM can influence exercise tolerance, probably by limiting activation of the contractile reserve.

Evaluation of the cardiomyopathy in Becker muscular dystrophy.

To evaluate the features and the course of cardiomyopathy in Becker muscular dystrophy, 68 patients--identified by clinical assessment and by reduced dystrophin labeling and/or DNA analysis--were followed in the years 1976-1993, for periods ranging from 3 to 18 years (mean 8). Patients periodically underwent clinical, electrocardiographic, echocardiographic, nuclear, and radiological assessments. Preclinical cardiac involvement was found in 67.4% of patients under 16 years of age, decreasing to 30% in patients older than 40. Clinically evident cardiomyopathy was found in 15% of patients under 16 years of age, increasing to 73% in patients older than 40. A real, dilated cardiomyopathy is the most frequent type of myocardial involvement after the age of 20. Results show that the severity of cardiac involvement can be unrelated to the severity of skeletal muscle damage and confirm that cardiac dysfunction is a primary feature of Becker muscular dystrophy.