We evaluated the contribution of intramural electrical events in initiation and maintenance of ventricular tachycardia in 15 dogs 3-8 days after either permanent (n = 2) or transient (n = 13) coronary artery occlusion. Seven of the dogs (47%) demonstrated eight distinct monomorphic ventricular tachycardia patterns which were mapped by means of a recently designed computerized system capable of ...

Since the operation of mitral valvotomy was introduced, various attempts have been made to explain the high incidence of histologically active lesions in biopsies of the left atrial appendages removed at operation, in view of the low incidence of active lesions found at necropsy in clinically inactive cases of rheumatic heart disease. Several clinico-pathological studies have been made in biops...

Case: A 73-year-old woman is referred for management of recurrent ventricular tachycardia (VT). She had suffered an inferior wall myocardial infarction in 1970. Fifteen years later, she presented with a wide QRS tachycardia, palpitations, and dizziness. Therapy with amiodarone was initiated but discontinued in 1997 because of toxicity, and she received an implantable cardioverterdefibrillator (...

Pairs of ultrasonic dimension gauges and a micromanometer implanted in the subendocardium of the left ventricles of unanesthetized dogs were used to analyze serial changes in hemodynamic status and segmental function for up to 4 weeks after permanent circumflex coronary artery occlusion. Regional function was studied in control segments and in segments identified as marginal (hypokinetic) and i...

AIMS We examined the left lateral ridge (LLR) between the orifices of the left pulmonary veins and the left atrial appendage for a better understanding of its structural composition relevant to ablations for atrial fibrillation (AF). METHODS AND RESULTS The LLR and its surrounding areas were studied in 40 heart specimens by dissection and histological sections. The LLR is a fold of the atrial...

Experimental myocardial ischemia produced in dogs by proximal left anterior descending coronary artery (LAD) ligation results in a small but measurable decrease in total phospholipid content in the subendocardium of the ischemic region. After 3 hours of fixed occlusion, there is a 10% decrease in total phospholipid content. Silica gel chromatography reveals this decrease to be reflected predomi...

The coronary capillary flow is analyzed theoretically based on continuum mechanics. The capillary is a long, elastic, and permeable vessel loaded externally by tissue pressure, and it is subject to possible periodic length changes, together with adjacent myocytes. Capillary flow is driven by arteriolar-venular pressure difference. Ultrafiltration due to transmural hydrostatic and osmotic gradie...

BACKGROUND Impaired endothelial-dependent vascular responses after coronary artery occlusion (CAO) and reperfusion (CAR) have been investigated extensively. However, it is not known whether impaired endogenous endothelium-derived relaxing factor production affects postischemic myocardial dysfunction, ie, myocardial stunning. METHODS AND RESULTS Eight dogs were instrumented with an intracorona...

OBJECTIVE The delayed phase of ventricular arrhythmias during acute ischemia (phase-1b arrhythmia) is associated with depletion of catecholamines and cell-to-cell uncoupling between depressed depolarized intramural ischemic region and surviving cells in subepicardium and subendocardium. In the present study we determined the effects of uncoupling and catecholamines on development of proarrhythm...

BACKGROUND Previously, we showed by subtractive hybridization in a swine model of ischemia/reperfusion that an upregulation of genes participating in mechanisms of cell survival is a potential genomic mechanism to tilt the balance from necrosis to functional reversibility. METHODS AND RESULTS We present here the full-length sequencing and characterization of a novel gene that was found in thi...