Influence of residual myocardial ischaemia on induced ventricular arrhythmias following a first acute myocardial infarction

Objectives The purpose of this study was to assess the possible effect of r esidual myocardial ischaemia on induced ventricular arrhythmia during progr ammed ventricular stimulation in survivors of a first acute myocardial infa rction. Background Most deaths after hospital discharge for acute myocardial infarc tion are sudden and presumably arrhythmic. Sudden cardiac death results fro m a dynamic interaction of structural abnormalities and transient triggerin g factors. The role of myocardial ischaemia as a trigger for ventricular ar rhythmias remains unclear. We hypothesized that residual myocardial ischaem ia after a first acute myocardial infarction is a potent trigger for sustai ned ventricular tachyarrhythmias, particularly in the presence of an abnorm al myocardium. Methods and Results In this prospective study, programmed electrical stimul ation, coronary angiography and dipyridamole-thallium-201 scintigraphy sing le-photon emission computed tomography were performed in 90 consecutive sur vivors of a first acute myocardial infarction. Patients, divided in two gro ups - group 1 with induced ventricular tachyarrhythmia (n=24) and group 2 w ithout induced ventricular tachyarrhythmia (n=66) - were compared regarding residual myocardial ischaemia. The two groups were comparable in terms of mean left ventricular ejection fraction, infarct size and location, gender ratio, peak creatine kinase value, and extent of coronary disease. Residual myocardial ischaemia was detected in 32 patients: 15 (42.5%) belonged to g roup 1 and 17 (25.7%) to group 2. There was a statistically significant dif ference between the two groups regarding the presence and the extent of res idual myocardial ischaemia (P <0.05). Conclusion Residual myocardial ischaemia, revealed by dipyridamole-thallium -201 scintigraphy following a first acute myocardial infarction, might cont ribute to electrical instability evaluated by programmed ventricular stimul ation. (C) 2001 The European Society of Cardiology.