Inability to reach 85% of the predicted maximal heart rate for age during exercise stress testing (chronotropic incompetence) has been considered indicative of an uninterpretable or inadequate test. A new study from the Cleveland Clinic suggests that a submaximal heart rate response to exercise may be a significant independent risk factor for all-cause and cardiovascular death in individuals wi...

Twelve male patients, with effort angina and a history of cold intolerance, performed brief submaximal exercise bicycle tests with separation of inspiratory and room air. In one test, the patients exercised in a normal room (20°C), breathing either normal or very cold air (-35°C). In another test, environmental air \vas either normal or -10°C, and four combinations of inspiratory and room air w...

introduction: good functional capacity has a high negative predictive value (npv) in patients with known or suspected coronary artery disease (cad) similar to a normal gated myocardial perfusion imaging (gmpi). aim of this study was to evaluate npv of functional capacity during treadmill exercise in patients with normal gmpi in pakistani population. methods: this was a prospective study which ...

Early- and intermediate-term results of the arterial switch operation for D-transposition of the great arteries (D-TGA) are encouraging. However, questions remain about the long-term outcome for these patients, especially with regard to exercise performance. Preliminary studies have demonstrated normal endurance time on treadmills. However, data regarding aerobic capacity and cardiopulmonary fu...

BACKGROUND Current guidelines recommend that caffeinated products should be avoided for at least 12 hours prior to regadenoson administration. We intended to examine the effect of caffeine consumption and of timing of last dose on hemodynamic effects after regadenoson administration for cardiac stress testing. METHODS 332 subjects undergoing regadenoson stress testing were enrolled. Baseline ...

The optimal rate control target for atrial fibrillation (AF) in the setting of heart failure with reduced ejection fraction (HFrEF) is not defined. Prior clinical trials have demonstrated benefits AF ablation patients HFrEF, including recovery left ventricular (LVEF). However, it unknown if degree prior to affects outcomes. To evaluate whether pre-ablation impacts LVEF following HFrEF. A single...

This study investigated the effects of acute psychosocial stress on trapezius single motor unit discharge behaviors. Twenty-one healthy women performed feedback-controlled isometric contractions under conditions of low and high psychosocial stress in the same experimental session. Psychosocial stress was manipulated using a verbal math task combined with social evaluative threat that significan...

The tubular heart of tunicates is composed of a single layer of myoendothelial cells. The direction of contraction reverses every few minutes. The conduction times in both directions are the same. Conduction velocity was greatest in the middle of the arms of the V-shaped heart and slowest in the apex. The greater the heart length, the greater was the conduction velocity. The Q(10) of conduction...