ABSTRACT
We analysed a group of 35 consecutive patients with acute myocardial infarction-23 of the inferior, 12 of the anterior wall-who needed temporary pacing for bradycardiac arrhythmias. We observed in three patients ventricular tachycardias induced by pacemaker stimuli falling onto the vulnerable part of the cardiac cycle due to improper sensing. All three had an inferior myocardial infarction involving the right ventricle. Because the pacemaker electrode in this condition lies in the vicinity of the infarcted myocardium sensing problems occur more frequently and re-entry tachycardias can be triggered more easily. It represents a possible risk of pacemaker treatment in his group of patients who, on the other hand, often need cardiac pacing in the acute phase following the development of transient AV-block.
Subject(s)
Myocardial Infarction/complications , Pacemaker, Artificial/adverse effects , Tachycardia/etiology , Aged , Electrocardiography , Female , Humans , Male , Myocardial Infarction/therapy , Ventricular Fibrillation/etiologyABSTRACT
50 normotensive subjects (22 controls with no cardiac disease, 24 patients with coronary heart-disease, and 4 with early cardiomyopathy) were investigated with gated cardiac blood-pool scintigraphy before and during cold pressor stimulation. The controls had no change or a significant rise (p less than 0.005) in left ventricular ejection fraction and preserved normal myocardial-wall motion, whereas patients with coronary-artery disease or cardiomyopathy had a significant fall (p less than 0.001) in left ventricular ejection fraction and many developed abnormal regional wall motion despite the absence of angina pectoris. Cold pressor gated cardiac blood-pool studies were more sensitive than single-lead exercise electrocardiography (p = 0.03) in the detection of patients with severe coronary-artery disease without previous myocardial infarction.
