The prevalence of right bundle branch block (RBBB) in the setting of acute myocardial infarction (AMI) ranges from 3–29% 1-9 and many studies have shown that the occurence of RBBB with MI is associated with higher mortality10-15.
Materials and methods: We did a prospective observational study over 1 year duration in our centre. We included patients above 18 years of age presenting with acute Anterior wall myocardial infarction and RBBB. Those who presented within the window period of <12 hrs of onset of chest pain and with nil contraindications for thrombolysis were thrombolysed with streptokinase or tenecteplase. Those who presented >12 hrs of chest pain were treated with heparin and antiplatelets. Eligible and willing candidates were subjected to CAG.
Results: A Total of 53 patients included in our study. The mean age was 60.02 ±12.07 years (Range was 28 to 82 years). Majority were males (n=44, 83.02%). 50.94% (n=27) were diabetics, 33.9% (n=18) were hypertensives,62.2%(n=33) were smokers and 30.18%(n=16) were alcoholics. 64.2% (n=34) presented within 12 hrs of onset of chest pain and 35.8%(n=19) presented beyond 12 hrs. Out of the 34 pts,67.65%(n=23) were lysed with tenecteplase and 32.35%(n=11) were lysed with streptokinase. As per Killips classification, 90.6%(n=48) were class ≥ 2 at presentation, out of which 31.25%(n=15) had cardiogenic shock (killips class 4). TIMI risk score at presentation was >6/14 in 79.24%(n=42) of patients. Ejection fraction was<30% in 37.73% (n=20) patients. Ventricular arrhythmias occurred in 30.2%n=16 patients. CAG was done in 62.2%(n=33) patients, TVD was seen in 15.15% (n=5) DVD was seen in 6.06%(n=2) LMCA lesion seen in 9.1%(n=3) patients. LAD lesion found in 81.8% (n=27) patients out of which 74.1%(n=20) had lesion in proximal LAD astriding S1, 18.5%(n=5) had osteoproximal lad lesion and 7.4%(n=2) had proximal LAD cut off. TIMI flow grade was 0/1 in the infarct related artery in 90.9%(n=30) of patients. PCI was done in 63.6%(n=21). Mortality was seen in 41.5%(n=22) of patients during the hospital stay and majority of deaths (59.09%,n=13) occurred within 48 hrs of admission. Mortality rate was less (26.4%,n=9) among those thrombolysed compared to those not thrombolysed (68.42%,n= 13) Important predictors of mortality were age≥60 yrs, late presentation, low ejection fraction<30% and occurrence of ventricular arrhythmias.
Conclusion: Hence identification of AMI with RBBB in ECG at presentation may help to identify the subset of patients with higher cardiac failure, arrhythmias and mortality and hence may provide prognostic information and hence guide early risk stratification.