Electrocardiographic exercise stress testing: An update beyond the ST segment

High-frequency QRS analysis compared to conventional ST-segment analysis in patients with chest pain and normal ECG referred for exercise tolerance test

“…Usually, previous conventional techniques for ECG detection of exercise-induced myocardial ischemia have relied on identification of repolarization abnormalities manifested as ST-segment changes in the 0.05-Hz to 100-Hz frequency band [27,28]. HFQRS analysis, in order to increase the diagnostic capabilities of exercise ECG, is based on detection of specific depolarization changes caused by ischemia.…”

Heart-rate recovery index in patients with chronic idiopathic urticaria

“…If this decrease is high, the risk of cardiovascular mortality is also low 9 . Sympathetic hyperactivity increases cardiovascular load and hemodynamic stress and makes patient vulnerable to endothelial dysfunction, coronary artery spasm, left ventricular hypertrophy, severe arrhythmias, stroke and cardiac mortality 18 . In contrast, increased parasympathetic activity reduces blood pressure and heart rate and prevents ischemic arrhythmias 19 .…”

“…It was reported that elevated sympathetic activity increases mortality rates by disrupting hemodynamic mechanisms 11 . It is shown that decreased HRR index is an independent risk factor for cardiovascular mortality 12,13 .…”

Quantifying Exertion Level During Exercise Stress Testing Using Percentage of Age-Predicted Maximal Heart Rate, Rate Pressure Product, and Perceived Exertion

“…The results of the current study are highly relevant to primary care physicians because ensuring an appropriate level of exertion during exercise stress testing is recognized as a clinically important goal. 24 …”