The exploration on the value of risk stratification between QRS duration and old myocardial infarction

Objective To analyze the occurrence of ventricular arrhythmia in old myocardial infarction (OMI) patients who combined with pathologic Q wave and fragmentation QRS (fQRS), and explore the relationship between QRS duration and ventricular arrhythmia. Methods Three hundred and thirty-five patients with OMI were examined with dynamic electrocardiogram, and they were divided into QRS duration≥ 110 ms group (M group, 57 cases) and QRS duration <110 ms group (N group, 278 cases). The incidence of ventricular arrhythmia was compared between 2 groups. The patients in M group and N group were divided into simple fQRS group (Ma, Na group), simple pathological Q wave group (Mb, Nb group), both group (Mc, Nc group) and none group (Md, Nd group). The incidences of ventricular arrhythmia among the subgroups were comparatively analyzed. Results The incidences of premature ventricular beats>720 beats/24 h, polymorphic ventricular extrasystoles, pairing ventricular extrasystoles, non-sustained ventricular tachycardia and ventricular escape in M group were significantly higher than those in N group: 38.60% (22/57) vs. 16.55% (46/278), 22.81% (13/57) vs. 7.55% (21/278), 43.86% (25/57) vs. 20.50% (57/278), 19.30% (11/57) vs. 3.96% (11/278) and 14.04% (8/57) vs. 3.96% (11/278), and there were statistical differences (P 0.05). In N group, the incidences of premature ventricular beats >720 beats/24 h in Na, Nb, Nc and Nd group were 24.73% (23/93), 13.64% (6/44), 25.81% (8/31) and 8.18% (9/110); the incidences of pairing ventricular extrasystoles were 30.11% (28/93), 15.91% (7/44), 29.03% (9/31) and 11.82% (13/110), and there were significant differences (P 720 beats/24 h of Nc group >Na group >Nb group >Nd group, and the incidence of pairing ventricular extrasystoles of Na group >Nc group >Nb group > Nd group. The incidences of polymorphic ventricular extrasystoles and non-sustained ventricular tachycardia in Ma group were significantly higher than those in Na group: 34.78% (8/23) vs. 11.83% (11/93) and 30.43% (7/23) vs. 6.45% (6/93), and there were statistical differences (P 720 beats/24 h, polymorphic ventricular extrasystoles and pairing ventricular extrasystoles in Md group were significantly higher than those in Nd group: 4/13 vs. 8.18% (9/110), 3/13 vs. 2.73% (3/110) and 6/13 vs. 11.82% (13/110), and there were statistical differences (P<0.05 or <0.01). Conclusions The longer QRS duration in OMI patients, the higher risk of ventricular arrhythmia. The ventricular arrhythmia risk is positively correlated with QRS duration in OMI patients with fQRS. There is still risk of ventricular arrhythmia in well recovered OMI patients (those without pathological Q wave and with fQRS), and it is positively correlated with QRS duration. There is a higher incidence of ventricular arrhythmia in OMI patients with QRS duration≥110 ms, but it is not significantly correlated with the pathological Q wave and fQRS. Simple fQRS and fQRS with pathologic Q wave in OMI patients with QRS duration<110 ms is significantly correlated with ventricular arrhythmia. Key words: Arrhythmia; Coronary disease; Myocardial infarction