We studied whether emission computed tomography (ECT) with 123I-labeled 15-(p-iodophenyl)-3R,S-methylpentadecanoic acid (BMIPP) shows myocardial distribution different from 201Tl in hypertrophic cardiomyopathy. In 10 patients with asymmetric septal hypertrophy (ASH), 5 with diffuse hypertrophy and 2 with apical hypertrophy, ECT was acquired 30 min (early) and 4 hr (late) after injection of 123I...

In 15 open-chest, anesthetized dogs, regional systolic wall thickening (% delta WT) was measured with sonomicrometry and regional blood flow was determined with tracer microspheres (7-10 micron) before and after various degrees of coronary artery narrowing were created with a hydraulic occluder. The stenoses were categorized into four groups by the effect on % delta WT, and the corresponding my...

The effect of ischemic subendocardial dysfunction on contractile function in the normally perfused subepicardium remains controversial. Accordingly, regional wall thickening (WT) was measured directly in the left ventricle of 10 open-chest dogs using epicardial echocardiography. Two silk sutures, used as echocardiographic targets, were inserted beneath the transducer to a depth of 25.0 +/- 0.7%...

BACKGROUND Nitric oxide (NO) causes vasodilation by stimulation of guanylate cyclase in vascular smooth muscle to produce cGMP. The resultant vasodilator effect is regulated by a family of cGMP phosphodiesterases (PDEs). Sildenafil, a selective inhibitor of PDE5 used for treatment of erectile dysfunction, has been found to cause relaxation of isolated epicardial coronary artery segments. The pr...

We ligated the left anterior descending coronary artery for 1 or 2 h in 31 purebred beagles. We did not detect any changes in beta-adrenergic receptor density or affinity when normal and ischemic zones were compared, either in the subendocardium or in the subepicardium. In the ischemic zones, there was a significant decline in all measures of adenylate cyclase activity, including activity media...

Evidence is presented supporting the hypothesis that the positive inotropic effect after an abrupt increase in systolic pressure (Anrep effect) is the recovery from subendocardial ischemia induced by the increase and subsequently corrected by vascular autoregulation of the coronary bed. Major evidence consists of data obtained from an isolated heart preparation showing that the Anrep effect can...

BACKGROUND This study was designed to assess whether cardiovascular magnetic resonance imaging (CMR) in Duchenne muscular dystrophy carriers (DMDc) may index any cell milieu elements of LV dysfunction and whether this cardiac phenotype may be related to genotype. The null hypothesis was that myocardial fibrosis, assessed by late gadolinium enhancement (LGE), might be similarly accounted for in ...

Previous studies have shown that left atrial pressure increases when measured relative to pleura! pressure during positive end-expiratory pressure (PEEP). We studied the factors leading to this increase in anesthetized mechanically ventilated dogs. Cardiac output was maintained nearly constant before and during PEEP, and heart rate did not change. Left atrial pressure measured relative to pleur...

The goal of this study was to examine the transmural distribution of ryanodine receptors in left ventricular (LV) hypertrophy (LVH) and its in vivo consequences. Dogs were chronically instrumented with an LV pressure gauge, ultrasonic crystals for measurement of LV internal diameter and wall thickness, and a left circumflex coronary blood flow velocity transducer. Severe LVH was induced by chro...

Intact cardiomyocytes are increasingly being used to investigate the molecular mechanisms of contraction and to screen new therapeutic compounds. The function of the cardiomyocytes is often measured from the calcium transients and sarcomere length profiles. We studied the role of experimental temperature and transmural region on indices of function in freshly isolated, unloaded cardiomyocytes. ...