Effects of Primary PCI on Acute Inferior ST-Elevation MI With Complete Heart Block

Background: Complete heart block is a common complication among patients with acute inferior myocardial infarction (MI) and leads to increased mortality. The aim of this study was to evaluate complete atrioventricular block after mechanical revascularization (primary percutaneous coronary intervention [PCI]) in acute inferior MI. Methods: This retrospective study enrolled 418 patients with acute inferior MI, who underwent primary PCI in Rajaie Cardiovascular, Medical, and Research Center between 2011 and 2014. Thirty-eight (9%) patients had complete heart block. Three patients expired < 14 days after PCI and were excluded from the study due to lack of follow-up. The restoration of the sinus rhythm, need for permanent pacemaker (PPM) implantation, and heart-block recovery time were compared between the other 35 patients. Results: Among the 35 patients, the sinus rhythm was restored in 34 cases after a mean time of 50 hours. In 1 case, 14 days after primary PCI, PPM implantation was done due to the persistence of the heart block. Neither the restoration of the sinus rhythm and nor PPM implantation had a statistically significant correlation with primary PCI. Among the 34 patients, the heart-block recovery time was significantly longer (P < 0.05) in the diabetics and in those with QRS > 120 ms in the initial ECG. This time was significantly shorter in the patients undergoing successful stenting and the patients undergoing balloon angioplasty and was very significantly shorter in the patients with a TIMI flow of 3 after revascularization. In this study, the block recovery time was not correlated with the location of the lesions in the coronary arteries, with thrombosuction, and with IIb/IIIa inhibitor infusion. Age; gender; history of hypertension, dyslipidemia, and smoking; and very severe left ventricular dysfunction did not have any effect on this time. Conclusions: In light of the results of the current study, it can be concluded that mechanical revascularization in patients with acute inferior MI complicated with complete heart block is not effective on the restoration of the sinus rhythm and need for PPM implantation. Nonetheless, the heart-block recovery time is significantly decreased and correlated with successful stenting and balloon angioplasty.