Index After Acute Myocardial Infarction Research Articles

Decline in inducibility of sustained ventricular tachycardia from two to twenty weeks after acute myocardial infarction

To determine temporal evolution of sustained ventricular arrhythmias inducible after acute myocardial infarction (AMI), serial programmed ventricular stimulation (PVS) was performed in 27 patients 15 ± 4 and 150 ± 28 days after AMI. These patients did not have worsening of congestive heart failure or angina, coronary artery bypass surgery or spontaneous sustained ventricular tachycardia (VT) in the period between 2 PVS studies. During initial PVS, sustained VT or ventricular fibrillation (VF) was inducible in 17 patients (group I) and was not inducible in 10 (group II). Late PVS in group I induced sustained VT or VF in 8 patients (47%) and nonsustained VT or no VT in 9 (53%). A decrease in late inducibility of sustained VT VF was greater for arrhythmias induced during initial PVS by triple extrastimuli and burst pacing than for those induced by double extrastimuli (88% vs 25%, p < 0.04), but appeared to be unrelated to the morphologic characteristics or cycle length of the initially induced sustained VT or VF and to other clinical, hemodynamic or angiographic variables. During late PVS in 10 group II patients, sustained VT or VF remained noninducible in 9 (90% concordance); in 1 patient sustained VT was induced. During a mean follow-up of 14 ± 5 months since late PVS, none of 27 patients had spontaneous sustained VT and 2 patients in group I died suddenly. Thus, in survivors of AMI, inducibility of sustained VT or VF decreased by half during late PVS performed 5 months after the index AMI, but noninducibility 2 weeks after AMI had a high long-term reproducibility. These findings indicate the presence of an unstable electrophysiologic substrate in the first 3 to 6 months after AMI and should be taken into consideration when interpreting the results of PVS in patients with relatively recent myocardial infarction.

Association between transient pulmonary congestion during acute myocardial infarction and high incidence of death in six months

In a prospective multicenter study of 866 patients after acute myocardial infarction (AMI), an increased or excessive mortality rate (13%) was confined to the first 6 months after AMI. In the subsequent 18 months of follow-up, the mortality rate (4%) was similar to that in coronary patients in chronic stable condition. Analysis of patients who died in the first 6 months revealed that 55% had had pulmonary congestion at the time of the index AMI. Neither these patients nor the others who died in the early period were found to have more severe ventricular dysfunction, more malignant arrhythmias or more severe ischemia than patients who died after 6 months. The reason for the high and early mortality in patients with pulmonary congestion is not clear, particularly because 30% had reasonable ventricular function, with an ejection fraction of more than 40%. However, given the poor prognosis of these patients, early and aggressive diagnostic efforts should be undertaken to exclude jeopardized regions remote from the initial AMI.