[Is Q-wave on admission associated with microvascular injury in patients with acute myocardial infarction treated with primary angioplasty?].

Introduction: Impaired microvascular flow, despite patent epicardial artery (no-reflow phenomenon), leads to greater left ventricular dysfunction after myocardial infarction (MI). Predictive factors associated with no-reflow remain largely unexplored. Q-wave on admission (Q(A)) is a sign of extensive ischemia probably predisposing to no-reflow. The aim of the study was to explore possible relation between Q(A) and electrocardiographic signs of no-reflow in patients with first MI.

Material And Methods: The study group was composed of 108 patients (81 men; mean age 60+/-11 years), with first ST-segment elevation MI, treated successfully with primary angioplasty (p-PTCA). ECG tracings were obtained before and 30 minutes after p-PTCA. The sum of ST-segment elevations (sum(ST(el))) in 3 contiguous leads with the highest ST(el) was calculated. Lack of 50% reduction of the sum(ST(el)) 30 minutes after angioplasty was defined as ECG sign of no-reflow. Presence of Q(A) was estimated in leads with ST(el).

Results: Q(A) was found in 42 (39%) patients. Q(A) was more often observed in patients with ECG signs of no-reflow (38% vs. 18%; p<0.05). Group with Q(A) showed larger damage of left ventricle estimated with ECG QRS score (7.7+/-4.4 vs. 6.1+/-3.4; p<0.05) as well as worse ejection fraction (42% vs. 46%; p=0.05).

Conclusions: Patients with Q(A) have more often ECG signs of no-reflow than other patients with MI. Previously described worse function of left ventricle in this group, may be partially caused by more frequent no-reflow occurring in those patients. This fact suggests that adjunctive therapy preventing no-reflow could be beneficial in this group of patients.