Expanding benefits from cardiac resynchronization therapy to exercise‐induced left bundle branch block in advanced heart failure

Fernando L Scolari,Anderson D Silveira,Maurício Pimentel,Livia A Goldraich,Willian R Menegazzo,Ana Paula Chedid Mendes,Nadine Clausell

doi:10.1002/ehf2.12580

Abstract

Indications of cardiac resynchronization therapy (CRT) do not include exercise‐induced left bundle branch block, but functional impairment could be improved with CRT in such cases. A 57‐year‐old woman with idiopathic dilated cardiomyopathy (ejection fraction 23%) presented with New York Heart Association Class IV and recurrent hospitalizations. During heart transplant evaluation, a new onset of intermittent left bundle branch block was observed on the cardiopulmonary exercise test. CRT was implanted, and 97% resynchronization rate was achieved. In 12 month follow‐up, both clinical and prognostic exercise parameters improved. In patients with heart failure with reduced ejection fraction and no left bundle branch block at rest, exercise test can uncover electromechanical dyssynchrony that may benefit from CRT.

Highlights

Exercise-induced left bundle branch block (EI-LBBB) is rarely observed in exercise testing being associated with worsening symptoms during exertion and adverse prognosis.[1]
To the best of our knowledge, this is the first report of Cardiac resynchronization therapy (CRT) implantation in a patient with advanced heart failure and severe exercise limitation attributed to EI-LBBB
This observation highlights the relevance of exercise evaluation in patients with advanced heart failure to better understand their symptomatology, which may be related to the broadening of the QRS complex during exertion; this patient was severely limited under minimal activities, the exercise test uncovered a EI-LBBB

Summary

Introduction

Exercise-induced left bundle branch block (EI-LBBB) is rarely observed in exercise testing being associated with worsening symptoms during exertion and adverse prognosis.[1] Cardiac resynchronization therapy (CRT) is an established therapy for patients with heart failure with reduced ejection fraction and resting left bundle branch block (LBBB).[2] Potential benefits of biventricular pacing in patients who develop LBBB during exercise are uncertain, and current guidelines do not provide recommendations for resynchronization therapy in this situation. At the second minute of exercise, at a heart rate of 131 bpm, the patient developed LBBB with widening of the QRS to 200 ms. This finding persisted into the recovery phase (Figure 1). Reverse cardiac remodelling and improvement in ejection fraction were noticed (Table 1)

Discussion

Findings

44 NA 66 58 23 25