PO-04-017 'LEFT' BROKEN AFTER EXERCISE: A CASE OF PAINFUL LBBB SYNDROME SUCCESSFULLY TREATED WITH LEFT BUNDLE BRANCH AREA PACING

Abstract

The leading causes of new-onset left bundle branch block (LBBB) include coronary artery disease, hypertension, and cardiomyopathies. However, when the LBBB occurs in the absence of ischemia, in a rate-dependent manner, usually with exertion, it constitutes a painful left bundle branch block. Although there are multiple case reports of this entity, the mechanism, pathophysiology, and treatment are not well defined. We intend to raise awareness of this syndrome and highlight our unique treatment approach. NA A 57-year-old male presented to the cardiology clinic with exertional chest pain and palpitations. He underwent an exercise ECG test, surprisingly on stage 2 of Bruce protocol, at around a heart rate of 116 bpm; he started developing LBBB on every other beat. At a heart rate of 125 bpm, he developed persistent LBBB associated with similar symptoms, both of which persisted in the recovery phase (Figure 1). His Echocardiogram was normal. Invasive coronary angiography revealed normal coronaries. Previous case reports have shown that cardiac rehabilitation helps to delay the onset of LBBB to a higher heart rate; however, he opted for pacemaker implantation as he had severe exercise limitations. He underwent a biventricular-implantable pacemaker with right atrial, left bundle branch area, and coronary sinus (CS) left ventricular (LV) leads. The pacemaker was programmed DDD60 with a rate adaptive AV interval with a start rate of 80 bpm. This would enable the LBB area pacing above a heart rate of 80 bpm. Within one week of implantation, the patient had a complete resolution of his symptoms. A cardiopulmonary exercise test to assess VO2 with pacing programmed off and then on is scheduled as part of the follow-up. The symptoms of the painful LBBB syndrome can be quite severe, resulting in physical and psychological debilitation. Treatment with a physical exercise regimen has been successful as it delays the LBBB onset to a higher heart rate. However, the patient loses the benefit once they stop exercising. A definitive solution is a pacemaker; there are multiple case reports of His bundle and right ventricular pacing, which successfully treated this syndrome. In this case, we used a unique approach of pacing just the LBBB area; in addition, a CS LV lead was placed, which could be used for an earlier activation of the LV if the patient needs that in the future.