Alterations of cardiac rhythm and conduction occur frequently during exercise stress testing and may provide significant information regarding cardiovascular status. Exertion may induce arrhythmias as a result of sympathetically enhanced phase 4 depolarization of ectopic foci or the induction of myocardial ischemia secondary to increased myocardial oxygen demand. Exercise may abolish arrhythmias present in the resting state, an effect attributed to overdrive suppression and inhibition related to sinus tachycardia. Although a wide spectrum of electro-physiologic changes may be elicited by stress testing, ventricular dysrhythmias are of primary importance. Premature ventricular contractions that are frequent, multifocal, repetitive or associated with light work loads have been particularly indicative of coronary artery disease. Exertional ventricular irritability has been observed more frequently in patients with coronary atherosclerosis involving two or more coronary vessels and accompanied by abnormalities of left ventricular wall motion. Exercise testing may have advantages over portable monitoring in the detection of ventricular arrhythmias. The mere presence of ventricular ectopic beats at rest does not preclude carefully performed graduated stress testing nor does their disappearance during effort exclude the presence of coronary artery disease.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine