Ventricular late potentials and left ventricular function after early enalapril treatment in acute myocardial infarction

Effects of early captopril therapy after myocardial infarction on the incidence of late potentials

BACKGROUND

Late potentials (LP) on signal-averaged electrocardiography (SAECG), recorded 6 to 30 days after an acute myocardial infarction (AMI), identify patients at risk for late arrhythmic events. Angiotensin-converting enzyme (ACE) inhibitors have been shown to reduce ventricular remodeling and cardiovascular mortality after AMI.

HYPOTHESIS

The aim of this study was to investigate the effect of early (< 24 h) administration of captopril on the presence of LP on Days 6-30 after AMI.

METHODS

The study included 117 patients with a first AMI; 63 patients (53 men and 10 women, aged 59 +/- 12 years), 35 with an anterior and 28 with an inferior AMI (44 thrombolyzed), received early captopril therapy. The control group consisted of 54 age-matched patients (39 men and 15 women, aged 60 +/- 12 years), 19 with an anterior and 35 with an inferior AMI (31 thrombolyzed, p = NS), who did not receive early therapy with an ACE inhibitor. The mean left ventricular ejection fraction was similar in both groups (48 vs. 46%). Time domain analysis of SAECG was performed using a band-pass filter of 40-250 Hz. Late potentials were considered present if any two of three criteria were met: (1) Filtered QRS duration (QRSD) > 114 ms, (2) root-mean-square voltage of the last 40 ms of the QRS complex (RMS) < 20 microV, and (3) duration of low amplitude (< 40 microV) signal of the terminal portion of the QRS (LAS) > 38 ms.

RESULTS

In the two groups of patients there were no differences in mean values of SAECG parameters. No patient was receiving any antiarrhythmic drugs. In the captopril group LPs were present in 9 of 63 patients (14%) and in the control group in 17 of 54 patients (31%) (p = 0.046). There was no difference in the number of patients with a patent infarct-related artery in the two groups (76 vs. 59%).

CONCLUSION

Captopril treatment early after an AMI reduces the incidence of LPs recorded on Days 6-30 and may thus favorably affect the arrhythmogenic substrate.

Effects of early losartan therapy on ventricular late potentials in acute myocardial infarction

BACKGROUND

Ventricular late potentials (LPs) obtained by the signal-averaged electrocardiogram (SAECG) have prognostic significance as independent predictors of arrhythmic events after an acute myocardial infarction (AMI). Angiotensin receptor blockers reduce the overall mortality and risk of sudden cardiac death in postinfarction patients. The aim of this study was to investigate the effect of early losartan therapy on ventricular LPs, a noninvasive method for the evaluation of arrhythmogenic substrates in AMI patients.

METHODS

The study included 97 patients with their first AMI. Forty-eight patients (39 men and 9 women, aged 58.8 +/- 13.19 years), received early losartan therapy. The control group consisted of 49 patients (38 men and 11 women, aged 59.55 +/- 11.0 years), did not received early losartan therapy. The SAECG was performed at admission and day 14.

RESULTS

The baseline clinical, angiographic characteristics, and reperfusion methods were similar in both groups. The baseline SAECG findings were also similar in the two groups. There was a significant decrease in the rate of LP, between the first and last SAECG recordings, after reperfusion therapy in the losartan group. All of the parameters of LPs were significantly improved in the losartan group on the last SAECG recordings.

CONCLUSION

The results of this study showed that losartan treatment, early after an AMI, reduced the incidence of LP and may thus favorably affect arrhythmia substrates.