Nonsustained Ventricular Tachycardia in the Setting of Acute Myocardial Infarction

Abstract

Background-Nonsustained ventricular tachycardia (NSVT) has significant prognostic implications in the setting of healing and healed myocardial infarction (MI), but only limited information is available on its importance in the setting of acute MI. We evaluated the prognostic significance of NSVT characteristics in the setting of acute MI. Methods and Results-A prospective database was used to identify 112 patients with NSVT within 72 hours of acute MI.A control group was identified matched for age, sex, type of MI, and thrombolytic treatment. Mean age was 64 to 65 years in the 2 groups with 71% to 72% men. Q-wave MI was noted in 52% to 53%, and thrombolytic therapy was administered to 31% to 32% of patients in each group. In-hospital ventricular fibrillation occurred more frequently in the NSVT group (9% versus 0% in the control group; PϽ0.001), but total in-hospital (10% versus 4%) and follow-up mortality (10% versus 17%) did not differ between the 2 groups. With a Cox regression model, specific NSVT characteristics were predictive of mortality. The strongest predictor was time from presentation to occurrence of NSVT. Shortest RR interval during NSVT was also a univariate predictor of mortality. Multivariate analysis identified time from presentation to occurrence of NSVT as the strongest predictor of mortality (PϽ0.0001). The increased relative risk of NSVT was first significant when it occurred 13 hours from presentation and continued to increase as the time from presentation to occurrence of NSVT increased, plateauing at Ϸ24 hours with a relative risk of 7.5. Conclusions-Contrary to prevailing clinical opinion, NSVT that occurs in the setting of acute MI does have important prognostic significance. Specifically, the currently accepted notion that NSVT that occurs within 48 hours of acute MI has no prognostic significance needs to be adjusted. Although NSVT that occurs within the first several hours of presentation does not have an associated adverse prognosis, NSVT that occurs beyond the first several hours after presentation is associated with significant increases in relative risk. (Circulation. 1998;98:2030-2036.)

Relationship Between Nonsustained Ventricular Tachycardia After Non–ST-Elevation Acute Coronary Syndrome and Sudden Cardiac Death

“…Key Words: acute coronary syndrome Ⅲ antiarrhythmic drugs Ⅲ death sudden Ⅲ electrocardiography Ⅲ ventricular tachycardia V entricular ectopy is frequent in patients hospitalized with acute coronary syndromes (ACS). [1][2][3][4] The clinical implications of nonsustained ventricular tachycardia (VT) after ACS remain uncertain, in particular relative to the risk of sudden cardiac death (SCD) in patients with shorter episodes of ventricular ectopy as well as the relationship between the timing of VT after hospital admission and prognosis. Most studies that investigated the incidence of ventricular arrhythmias in the presence of ACS and the relationship with SCD focused on sustained VT and were carried out before widespread use of reperfusion, revascularization, or contemporary medical therapy.…”

“…Results of a number of studies of acute myocardial infarction, the majority of which focused on STEMI, have shown that ventricular ectopic activity is common (40% to 70%) during hospitalization, with 5% to 10% of patients experiencing an episode of nonsustained VT. [1][2][3][4][5]20 In patients with STEMI, there is conflicting evidence on the relationship between VT and subsequent SCD, with several earlier studies demonstrating an independent relationship between VT and cardiovascular complications 1,5 and subsequent studies failing to find any relation- ship, especially when left ventricular function was considered, 4,21 although these findings have not been uniform. 6,7,22 Relatively little information is available on nonsustained VT in patients with NSTEACS.…”

ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

“…Such patients have generally been excluded from clinical trials for interventions targeting long-term arrhythmic death risk because of low absolute risk, but it remains unclear whether the magnitude of risk is modulated by the extent of myocardial damage that occurs during the acute event. The long-term risk implications of sustained VT and VF during the acute phase of MI may also be applied to frequent PVCs and runs of NSVT (32). It is important to stress that the clinician's ability to recognize individuals with reversible or transient causes of ventricular tachyarrhythmias is limited (33).…”

Diretrizes

“…Um estudo prospectivo demonstrou que a taquicardia ventricular que se manifesta até as primeiras 12 horas de evolução do quadro isquêmico agudo geralmente não está associada ao pior prognóstico após a alta. Entretanto, os pacientes que evoluem com essa arritmia após as 12 horas têm maior risco de morte súbita, principalmente quando a arritmia se manifesta após as 24 horas de evolução 468 . O tratamento dependerá da manifestação clínica do paciente.…”