THERE HAS BEEN much recent interest by clinical cardiologists in the question of myocardial "contractility" or "contractile state." To the clinician, the quest for a measure of "contractility" or "contractile state" becomes the quest for an early indication of myocardial disease that may be of prognostic value and open up the possibility of preventive measures to forestall serious myocardial di...

The influence of ATP-sensitive K+ channels (K(ATP) channels) on cardiac performance during anoxia and reoxygenation was investigated in two species of fish showing different cardiac responses to anoxia. Force production in isometrically contracting ventricular muscle preparations from yellowtail flounder is potentiated at the onset of anoxia, while force immediately declines in Atlantic cod pre...

A perfused rainbow trout heart was developed which generated its own intrinsic heart rate and a physiological power output. This preparation was used to examine the intrinsic mechanical properties of the trout heart, the dose-response effects of catecholamines and extracellular calcium on these properties, and the effects of catecholamines and extracellular calcium during exposure to acidotic c...

Chronic atrial fibrillation represents one of the main risk factors for the occurrence of thromboembolic events. At present it is clear that thrombus formation is triggered, not only by irregular rhythm, but also by reduced intrinsic atrial contractility. Apart from the thromboembolic risk, reduced atrial contractility might contribute to reduced cardiac output in patients with ventricular hear...

MicroRNAs (miRNAs) have a fundamental role in diabetic heart failure. The cardioprotective miRNA-133a (miR-133a) is downregulated, and contractility is decreased in diabetic hearts. Norepinephrine (NE) is a key catecholamine that stimulates contractility by activating β-adrenergic receptors (β-AR). NE is synthesized from tyrosine by the rate-limiting enzyme, tyrosine hydroxylase (TH), and tyros...

The effects of isoproterenol, norepinephrine, dobutamine, exercise, and nitroglycerin on left ventricular diameter, pressure, velocity of shortening, dP/dt, dP/dt/P, arterial pressure, left circumflex coronary blood flow, and coronary vascular resistance were examined in healthy conscious dogs with normal coronary perfusion and in the same animals after moderate global ischemia had been induced...

A 7-month-old girl with no medical history was treated with mechanical circulatory support due to myocarditis. Her cardiac contractility did not improve despite more than one week of extracorporeal membrane oxygenation treatment. Thus, we planned a heart transplant. However, a high level of cytomegalovirus was found in blood laboratory results by quantitative polymerase chain reaction. The pati...

Animal models that mimic human cardiac disorders have been created to test potential therapeutic strategies. A key component to evaluating these strategies is to examine their effects on heart function. There are several techniques to measure in vivo cardiac mechanics (e.g., echocardiography, pressure/volume relations, etc.). Compared to echocardiography, real-time left ventricular (LV) pressur...

Hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, primarily their HCN4 subtype, are one of the promising targets for development cardioprotective agents. HCN channel blockers have a selective bradycardic effect, preserving myocardial contractility and diastolic function not affecting electrophysiological parameters heart. This review continues series reviews on analysis compou...