Relations between fragmented QRS complex and ventricular arrhythmias in patients with a prior myocardial infarction.

BACKGROUND: The relationship between fragmented QRS and ventricular arrhythmias in patients with myocardial infarction (MI) is unclear. OBJECTIVE: To investigate the relationship between fragmented QRS complex (fQRS) on electrocardiography and the incidence of ventricular arrhythmias in patients with a previous MI. METHODS: A total of 321 patients with MI were divided into fQRS (n=167) and non-fQRS (n=154) groups. Standard 12-lead electrocardiography and 24 h Holter monitoring were performed in all patients. RESULTS: The incidence of frequent (28.7% versus 17.5%; P<0.05) or high-risk ventricular premature contractions (34.1% versus 23.4%; P<0.05) in the fQRS group was higher than in the non-fQRS group. The incidence of nonsustained ventricular tachycardia in the fQRS group was also higher than in the non-fQRS group (12.0% versus 4.5%; P<0.05). Patients with fQRS duration >0.12 s had a higher incidence of ventricular arrhythmias (70.6%) than patients with fQRS duration between 0.101 s and 0.119 s (42.6%; P<0.05), or those with fQRS duration of <= 0.10 s (22.9%; P<0.05). Logistic regression analysis showed that fQRS was an independent predictor for high-risk ventricular premature contractions (OR 1.482 [95% CI 1.19 to 3.22]; P=0.02) and nonsustained ventricular tachycardia (OR 1.982 [95% CI [1.30 to 3.76]; P=0.01). CONCLUSION: fQRS was associated with an increased incidence of high-risk ventricular premature contractions and nonsustained ventricular tachycardia. FQRS may be used to predict future risk of ventricular arrhythmias in patients with a previous MI.