title: The dependence of T wave alternans on diastolic resting period duration.
abstract: The dependence of T-wave alternans on diastolic resting period duration as well as on regional differences in monophasic action potential duration was studied in the in situ dog heart. T-wave alternans was elicited when diastolic resting period shortened to values less than 41 +/- 6% of the cardiac cycle. This could be attained either by increasing the driving rate, or lengthening action potential duration by inducing hypocalcemia. During T-wave alternans, monophasic action potentials recorded from anterior and posterior left ventricular surface showed an alternation in duration; the degree in alternation in both regions differed and related to T-wave polarity.
mesh_terms: D000200:Action Potentials; D000818:Animals; D001283:Atrioventricular Node / Q000502:physiology; D002304:Cardiac Pacing, Artificial; D003971:Diastole; D004285:Dogs; D004492:Edetic Acid / Q000494:pharmacology; D004562:Electrocardiography; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D009200:Myocardial Contraction; D016276:Ventricular Function
chemical_list: D004492:Edetic Acid