A comparative study of clinical profile and outcomes of patients with ischemic and non-ischemic complete heart block

摘要

Background: Complete heart block (CHB) is a medical emergencyand usually requires immediate intervention. Both cardiacischemia and non-ischemic conditions can cause CHB. The aim ofthis study is to compare baseline clinical characteristics associatedwith ischemic versus non-ischemic causes of CHB and theiroutcomes.Materials and Methods: This is a single center retrospective,observational study. Consecutive 250 patients with CHB fromJanuary to December 2016 were included. Patients were characterizedinto non-ischemic and ischemic groups based on cardiacmarker elevation, ECG changes and/or cardiac catheterization findings.The primary outcome was all-cause mortality and secondaryoutcome was pacemaker placement.Results: Out of 250 patients, 137 had ischemic and 113 hadnon-ischemic CHB. The mean age was 60.5 yrs in ischemic groupand 61.32 yrs in the non-ischemic group (p = 0.58). Patients withischemic CHB had a lower mean ejection fraction (EF) [44.2% vs55.2%, (p < 0.01)]. In the ischemic group, 55 patients (40%) presentedwith cardiogenic shock compared to 6 (0.07%) in the non-ischemicgroup (p < 0.001). Statistically significant difference was presentbetween ischemic and non-ischemic groups in diabetes mellitus(DM) (56.9% vs 45%, p = 0.006), dyslipidemia (13.1% vs 0.5%,p = 0.001) and smoking (31.3% vs 14.1%, p < 0.001). In the ischemicgroup, 112 patients had inferior wall myocardial infarction (IWMI)(81.7%) and 21 had anterior wall myocardial infarction (AWMI)(15.3%). Right coronary artery (RCA) was the most common culpritvessel (73%). Seventy patients underwent percutaneous coronaryintervention (PCI) and 10 were referred for coronary artery bypassgrafting (CABG). For outcomes, 8 out of 113 (0.07%)patients withnon-ischemic CHB died compared to 33 out of 137 (24.1%) ischemicCHB (p < 0.001). Permanent pacemaker was implanted in 76 out of113 patients (67.2%) in the non-ischemic group compared to 14 outof 137 (10.2%) in the ischemic group (p < 0.001).Conclusion: Patients with ischemic CHB have a lower EF withhigher mortality. Risk factors like diabetes mellitus (DM), dyslipidemiaand smoking are more frequent in the ischemic group andthey are less likely to get a permanent pacemaker compared tonon-ischemic CHB.