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Case Report

Fascicular Conduction Disturbances Post Re-Vascularization in Coronary Artery Disease

Volume 4, Oct 2015

Bhabani Sahoo, PG 1st year MD, Gaurav Thakre, PG 2nd year MD, B. V. Manjunath, MD, DM, Mangalore, India



Alternating bundle branch block is when both right bundle branch block (RBBB) and left bundle branch block (LBBB) patterns appear on the same electrocardiogram (ECG) or within a period of hours to days (1,2). Before the reperfusion era, it represented up to 6% of all forms of bundle branch blocks (3) following acute myocardial infarction, with 44% progression rate to high grade atrioventricular (AV) block (4). With the advent of modern reperfusion therapy, it is now less commonly encountered in clinical practice. Such rare ECG need to be analyzed closely.

Case Presentation

A 65-year-old male, known diabetic and dyslipidemic presented to cardiology out-patient department on 10/02/2016 with chief complaint of chest pain for one day. He reported a history of such intermittent chest pain for the last 3-4 months. Baseline ECG showed complete LBBB with sinus bradycardia (Figure 1). ECG taken 2 weeks prior also showed complete LBBB. No old ECGs were available to compare. A trans-thoracic Echocardiography was done which showed no left ventricular (LV) regional wall motion abnormality with normal LV systolic function. His blood investigations were unremarkable, except for elevated glycosylated hemoglobin.

In view of chest pain being suggestive of angina, associated with coronary risk factors such as diabetes mellitus and dyslipidemia, and evidence of LBBB on ECG, the patient was advised to undergo coronary angiogram. Coronary angiogram revealed single vessel disease with 95% stenosis in the mid-segment of the left anterior descending artery for which successful percutaneous coronary angioplasty with drug-eluting stent placement was done. However, approximately 30 minutes post revascularization, ECG showed a lower heart rate which was associated with complete RBBB with II degree AV block (Figure 2). Patient was hemodynamically stable and complained of mild chest pain. A check angiogram was done immediately which showed patent stent. Because of baseline LBBB with bradycardia, beta blockers and other heart rate lowering drugs were not initiated.
ECG taken on the following morning showed complete LBBB similar to the baseline ECG (Figure 3), which suggested that the new onset RBBB with LAHB with Ist and IInd degree AV block were transient and insignificant prognostically. Patient remained asymptomatic thereafter and was discharged in a stable condition.

Case Discussion

Transient bundle branch blocks with sinus bradycardia are known to occur at the time of acute coronary reperfusion and are often accompanied by some degree of hypotension. In our patient, hypotension was not present. Most of the times rhythm disturbances may actually indicate successful restoration of coronary flow but their specificity for successful reperfusion is limited (5). We are reporting this case because our patient had transient RBBB with left anterior hemiblock and Ist and IInd degree AV block on a relatively lower heart rate recorded in the same ECG. Another ECG recorded after a few hours suggested LBBB with sinus bradycardia on a relatively higher heart rate.


Although reperfusion arrhythmias may show a temporal clustering at the time of restoration of coronary blood flow in patients after successful revascularization, this brief electrical storm is generally innocuous and therefore no prophylactic antiarrhythmic therapy is necessary and specific treatment is not indicated, except in rare cases of symptomatic or hemodynamically significant reperfusion arrhythmias (6).

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2. Herper G, Korkmaz ME, Kilic A. Reperfusion arrhythmias: are they only a marker of epicardial reperfusion or continuing myocardial ischemia after acute myocardial infarction? Angiology. 2008;58:663-70.
3. Hindman MC, Wagner GS, JaRo M, Atkins JM, Scheinman MM, DeSanctis RW, Hutter AH Jr, Yeatman L, Rubenfire M, Pujura C, Rubin M, Morris JJ. The clinical significance of bundle branch complicating acute myocardial infarction. 1. Clinical characteristics, hospital mortality, and one year follow up. Circulation. 1978;58:679-88.
4. Hindman MC, Wagner GS, JaRo M, Atkins JM, Scheinman MM, DeSanctis RW, Hutter AH Jr, Yeatman L, Rubenfire M, Pujura C, Rubin M, Morris JJ. The clinical significance of bundle branch complicating acute myocardial infarction. 2. Indications for temporary and permanent pacemaker insertion. Circulation. 1978;58:689-99.
5. Jessica L. Mega, David A. Morrow. ST segment myocardial infarction management. In: Braunwald’s Heart Diseases. Chapter 52, Volume II. Elseviers, Saunders. 2015:1398.
6. American College of Emergency Physicians; Society for Cardiovascular Angiography and Interventions, O’Gara PT, Kushner FG, Ascheim DD, Casey DE Jr, Chung MK, de Lemos JA, Ettinger SM, Fang JC, Fesmire FM, Franklin BA, Granger CB, Krumholz HM, Linderbaum JA, Morrow DA, Newby LK, Ornato JP, Ou N, Radford MJ, Tamis-Holland JE, Tommaso CL, Tracy CM, Woo YJ, Zhao DX, Anderson JL, Jacobs AK, Halperin JL, Albert NM, Brindis RG, Creager MA, DeMets D, Guyton RA, Hochman JS, Kovacs RJ, Kushner FG, Ohman EM, Stevenson WG, Yancy CW. 2013 ACCF/AHA guideline for management of ST-Elevation myocardial infarction: A report of the American College of Cardiology Foundation/ American Heart Association Task Force on Practical Guidelines. J Am Coll Cardiol 2013;61:e78-140.