Is Right, the rightful sinister BBB in acute MI?
Presenter
Ganesh Thirunavukkarasu, MBBS, George Washington University Hospital, Arlington, VA
Ganesh Thirunavukkarasu, MBBS, George Washington University Hospital, Arlington, VA and Ramesh Mazhari, M.D., FSCAI, George Washington University, Washington, DC
Title
Is Right, the rightful sinister bundle branch block in acute MI?
Introduction
Patients with acute MI and bundle branch block (BBB) have poor outcomes. Guidelines recognize new onset LBBB as a STEMI-equivalent in the appropriate context. However, new onset RBBB in AMI is underrecognized for poorer outcomes and higher mortality. We present the clinical course of a patient who developed new RBBB after presenting with anterior-STEMI. Clinical Case
71 year-old Caucasian male with medical history of hypertension and hyperlipidemia, presented to the ER with acute onset crushing chest pain and diagnosed with anterior-STEMI. He was given Aspirin 324mg to chew and had HR 94 bpm, MAP 75mmHg, breathing 24/min, saturating 95% on room air. Exam revealed an anxious elderly male in mild distress, tachypneic, but no basal rales or peripheral edema. A repeat EKG in ER revealed new bi-fascicular block (RBBB+LAFB) with anterior ST segment elevations. He was enrolled in the ongoing DTU (door-to-unloading) trial. Subsequently while being set up on the cath table, he developed hypoxia with bradycardia and profound hypotension, needing brief ACLS/CPR with ROSC and return of baseline mental status. We then proceeded with standard of care thereafter. An Impella CP device was emergently placed via right CFA. Coronary angiogram performed via right radial artery revealed hazy distal LM 80% stenosis with 100% ostial LAD occlusion and hazy 50% ostial LCX stenosis with TIMI 3 flow. RCA had mild disease proximally. Runthrough guidewires were used to cross the LAD and LCX followed by predilatation of LAD, then aspiration thrombectomy, then intravascular ultrasound (IVUS) exam and kissing stents were deployed in LAD-LCX with proximal optimization using NC balloons. Final angiogram showed apical LAD embolization, no edge dissection and no perforation. A pulmonary artery (PA) catheter was placed via right CFV. PA saturation 69%, PA s/d 39/21mmHG, mean RA 15mmHg and PCWP 19mmHg. At the end of the procedure, the patient was on low dose norepinephrine drip, awake and responsive. Impella CP was at P6 power level and his MAP was 90mmHg. TTE revealed appropriately positioned Impella CP device, LVEF 15-20% with severe diffuse hypokinesis. Following days, his lactate normalized, weaned off norepinephrine, Impella CP weaned and removed. Renal function, hemoglobin remained stable. He was discharged home on day 5 with DAPT, high intensity statin and low dose GDMT for systolic HF. Discharge EKG revealed normal sinus rhythm with narrow QRS and inferior STT changes. Discussion
Anterior-STEMI has the worst prognosis among all infarct sites. RBBB is supplied by the proximal septal perforator branch of LAD, hence new RBBB or BB, may indicate proximal LAD occlusion with large infarct and possibly the highest incidence of cardiogenic shock and mortality among the various EKG patterns in STEMI. Recognizing this underappreciated BBB (in AMI) or BB early on may help clinicians to make appropriate treatment therapies and improve prognosis of patients.