Article

Effect of thrombolysis on heart rate variability and life-threatening ventricular arrhythmias in survivors of acute myocardial infarction

From the “Clinica del Lavoro” Foundation, IRCCS, Medical Center of Rehabilitation, Tradate, Division of Cardiology, Tradate, Italy
Journal of the American College of Cardiology DOI:10.1016/0735-1097(94)90497-9 pp.19-26

ABSTRACT Objectives. The aim of the present study was to determine the influence of early thrombolysis on ventricular tachyarrhythmias (clinical and inducible) and heart rate variability in survivors of myocardial infarction at high risk for life-threatening ventricular arrhythmias.Background, A greater electrical heart stability may be important in improving survival in patients treated with thrombolysis. Few data are available about the influence of fibrinolysis on postinfarction arrhythmic events and other prognostic variables, such as inducible ventricular tachycardia and heart rate variability.Methods. The study group comprised 51 consecutive patients who underwent electrophysiologic study within 30 days of infarction, owing to the presence of two or more of the following criteria: left ventricular ejection fraction <40%, late potentials and repetitive ventricular ectopic beats. Thirty patients underwent thrombolysis within 6 h of the onset of symptoms (Group A), and 21 received conventional treatment (Group B). Inducibility of sustained monomorphic ventricular tachycardia was tested in both groups, and the standard deviation of all normal RR intervals during 24-h Holter monitoring was calculated. All patients were prospectively evaluated for occurrence of arrhythmic events.Results. The two groups were similar with regard to left ventricular ejection fraction (mean ± 1 SD 38 ± 6% [Group A] vs. 36 ± 8% [Group B]). Ventricular tachycardia was induced in 6 (20%) of 30 Group A patients versus 14 (67%) of 21 Group B patients (p = 0.002). The standard deviation of normal RR intervals was higher in Group A than in Group B (113 ± 36 vs. 90 ± 39 ms, p = 0.05). In patients with anterior infarction, the standard deviation of normal RR intervals was higher in 19 patients with thrombolysis than in 16 patients with conventional treatment (118 ± 41 vs. 74 ± 24 ms, p = 0.0002). During a mean follow-up period of 23 ± 11 months, 4 (13%) of 30 Group A patients had an arrhythmic event versus 9 (43%) of 21 Group B patients (p = 0.04).Conclusions. After myocardial infarction, in high risk patients, thrombolysis significantly reduced the occurrence of arrhythmic events independently of left ventricular function. This effect may be related to both an improvement in electrical heart stability, as elucidated by electrophysiologic study, and a favorable action on the cardiac sympathovagal balance.

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    Article: Influence of residual ischaemia on heart rate variability after myocardial infarction.
    D Cerati, F Nador, R Maestri, M Mantica, A Binda, S Perlini, E Vanoli
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    ABSTRACT: Despite the growing evidence for the positive predictive value of depressed baroreflex sensitivity and/or reduced heart rate variability after myocardial infarction, the mechanisms involved in these autonomic alterations are not fully understood. Specifically, the possible influence of residual ischaemia has not been assessed. To address this problem we studied the spectral analysis of heart rate variability in 21 patients with a first myocardial infarction in whom the only clinical correlate was the presence of residual ischaemia, as documented by the positive response to both an exercise stress test and an echocardiographic stress test. Data from these patients were compared with those obtained in a group of postmyocardial infarction patients similar for several risk factors, age, site of myocardial infarction, but without residual ischaemia. Patients positive for residual ischaemia had lower power in the whole spectrum (1146 +/- 158 vs 1631 +/- 159 ms2, P = 0.032) as well as in the low and high frequency bands of heart rate variability. A nocturnal increase in high frequency was observed in those without residual ischaemia (from 167 +/- 35 to 242 +/- 51 ms2, +45%, P = 0.034), but not in those with residual ischaemia (from 111 +/- 19 to 141 +/- 29 ms2, +27%, ns). Thus, residual ischaemia reduces heart rate variability after myocardial infarction. The autonomic effects of residual ischaemia probably contribute to its negative prognostic value after myocardial infarction.
    European Heart Journal 02/1997; 18(1):78-83. · 10.48 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

16 patients
 
19 patients
 
21 Group B patients
 
24-h Holter monitoring
 
51 consecutive patients
 
electrical heart stability
 
electrophysiologic study
 
favorable action
 
heart rate variability
 
heart rate variability.Methods
 
inducible ventricular tachycardia
 
life-threatening ventricular arrhythmias.Background
 
mean follow-up period
 
monomorphic ventricular tachycardia
 
postinfarction arrhythmic events
 
repetitive ventricular ectopic beats
 
risk patients
 
study group
 
ventricular ejection fraction
 
ventricular function
 

Roberto F E Pedretti