Repolarisation and refractoriness during early ischaemia in humans

OBJECTIVES To determine whether effective refractory period (ERP) shortens or lengthens in the first minutes of ischaemia in humans, and the relation between ERP changes and action potential duration (APD). METHODS ERP and monophasic action potential duration (MAPD) were measured from a single left...

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Bibliographic Details
Published in:British heart journal 2000-10, Vol.84 (4), p.365-369
Main Authors: Sutton, P M I, Taggart, P, Opthof, T, Coronel, R, Trimlett, R, Pugsley, W, Kallis, P
Format: Article
Language:English
Subjects:
Action Potentials
Adult
Aged
Biological and medical sciences
Cardiac arrhythmia
Cardiac Pacing, Artificial
Cardiology. Vascular system
Cardiopulmonary Bypass
Cardiovascular disease
Cardiovascular Medicine
Coronary Disease - surgery
Coronary heart disease
Coronary vessels
Female
Heart
Humans
ischaemia
Male
Medical sciences
Middle Aged
Myocardial Ischemia - physiopathology
Myocardial Ischemia - therapy
Patients
refractoriness
repolarisation
Studies
Surgery
Time Factors
Ventricular Dysfunction, Left - physiopathology
Ventricular Dysfunction, Left - therapy
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Summary:OBJECTIVES To determine whether effective refractory period (ERP) shortens or lengthens in the first minutes of ischaemia in humans, and the relation between ERP changes and action potential duration (APD). METHODS ERP and monophasic action potential duration (MAPD) were measured from a single left ventricular epicardial site in 26 patients undergoing coronary artery surgery. Cardiopulmonary bypass was instituted and normothermia maintained. Refractory period was determined by the extrastimulus technique at a basic cycle length of 500 ms, at four times (group 1, 15 patients) or two times (group 2, 11 patients) the preischaemic diastolic threshold. A three minute period of ischaemia was instituted by aortic cross clamping between the input from the pump oxygenator and the heart. RESULTS After three minutes of ischaemia, mean (SEM) ERP lengthened from 232 (5) ms (control) to 246 (7) ms (p 
ISSN:1355-6037
0007-0769
1468-201X
DOI:10.1136/heart.84.4.365