Impact of Systemic Acidosis on the Development of Malignant Ventricular Arrhythmias After Reperfusion Therapy for ST-Elevation Myocardial Infarction

BACKGROUND: The aim of the present study was to examine the effect of systemic acidosis on the development of malignant ventricular arrhythmias, including sustained ventricular tachycardia and ventricular fibrillation (VT/VF), after reperfused ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: A total of 157 consecutive patients with a reperfused STEMI were examined. Patients were divided into 2 groups according to the presence or absence of systemic acidosis, defined as arterial blood pH <7.40 on admission. Serum creatine kinase and C-reactive protein (CRP) levels were serially measured. Systemic acidosis was observed in 53 patients (34%). There was no significant difference in coronary risk factors and arrival time from onset between the 2 groups. Estimated glomerular filtration rate (eGFR) on admission was lower in patients with acidosis than in those without (P=0.001). Patients with acidosis had a higher incidence of VT/VF (26% vs 4%, P<0.0001), especially within 48 h after STEMI (23% vs 3%, P=0.0002), than those without. The peripheral white blood cell count on admission was higher in patients with than in those without acidosis. Multivariate analysis showed that systemic acidosis was a strong independent predictor of VT/VF (relative risk =8.79, P=0.002) among variables including prior MI and eGFR <60 ml . min(-1) . 1.73 m(-2). CONCLUSIONS: Systemic acidosis was a significant determinant of VT/VF after reperfused STEMI and was associated with elevated serum CRP level. Systemic acidosis and subsequent inflammation after ischemia reperfusion may play an important role in the development of VT/VF.