Cardiac MRI is an accurate, noninvasive modality for assessing the structure and function of the murine heart. In addition to conventional imaging, MRI tissue tracking methods can quantify numerous aspects of myocardial mechanics, including intramyocardial displacement, strain, twist, and torsion. In the present study, we developed and applied a novel pulse sequence based on displacement-encode...

Studies on the role of a-adrenergic constrictor tone in the coronary vascular bed during ischemia were performed in dogs running on a treadmill. The animals were instrumented with a left ventricular pressure transducer, and regional systolic wall thickening (%WTh) was assessed by sonomicrometry in the anterior and posterior walls of the left ventricle. An intracoronary catheter was implanted ch...

To guide surgical therapy for ventricular tachycardia by preoperative endocardial catheter mapping, accurate anatomic localization of arrhythmogenic sites is mandatory. For this reason we developed a mathematical cineradiographic method to compute left ventricular sites relative to three anatomic reference points: the centers of aortic and mitral valve ostia and the left ventricular apex. To va...

We studied the effects of rapid atrial pacing during the final 10 minutes of a 70-minute, 31% reduction in coronary blood flow in anesthetized swine to understand the significance of apparent metabolic improvements during the initial 60 minutes of segmental ischemia. Within 5-10 minutes of ischemia, subendocardial phosphocreatine (PCr) and ATP were depleted to 47% and 63% of control, respective...

The correlation between the ST segment displacement and coronary blood flow in various hemodynamic conditions was studied. Five isolated, isovolumic contracting canine hearts were used. The left main and the right and left circumflex (LCx) coronary arteries were cannulated and perfused with support dog's arterial blood. Four pairs of Ag-AgCl ECG electrodes were attached to the epicardium and su...

T otal coronary occlusion without prior development of collateral circulation results in a wavefront of myocardial necrosis, which moves from subendocardium to subepicardium. The early restoration of flow by pharmacological or mechanical means may interrupt the development of necrosis, saving the jeopardized myocardium. Twenty years ago, experimental studies revealed an endogenous defense mecha...

Oxygen saturation of small arteries and veins (20-500 micron) was determined microspectrophotometrically in the hearts of 12 pentobarbital-anesthetized open-chest dogs. Hearts were removed, quick frozen in liquid propane, and O2 saturation was determined in blood vessels on a regional basis between and within ventricular walls. No significant differences existed in arterial O2 saturation betwee...

It is generally assumed that long QT syndrome (LQTS) is an arrhythmic disorder that occurs in patients with normal left ventricular systolic function. The present article by Haugaa et al challenges this assumption.1 One hundred and one patients with genetically documented LQTS were systematically compared to an age-matched unaffected control population for differences in regional contraction pa...

The autoimmune liver disease primary biliary cirrhosis (PBC) is associated with life-altering fatigue in ∼50% of patients. Previous work suggests that fatigued PBC subjects have evidence of autonomic dysfunction and may be at a higher risk of sudden cardiac death. The manifestation of this risk is not clear. This pilot study investigated whether alterations in cardiac torsion and strain could b...

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by a deficiency of alphagalactosidase A. The estimated birth prevalence of AFD ranges from 1:40,000 to 1:117,000 worldwide. Approximately 50% of patients with AFD may have cardiac involvement, and malignant arrhythmias are the predominant cause of the substantially increased morbidity and reduced life expectancy. Curr...