Painful left bundle branch block syndrome: Clinical and electrocardiographic features and further directions for evaluation and treatment.

BACKGROUND

Painful left bundle branch block (LBBB) is a rarely diagnosed chest pain syndrome caused by intermittent LBBB in the absence of myocardial ischemia. Its prevalence, mechanism, detailed electrocardiographic (ECG) features, and effective treatments are not well described.

OBJECTIVES

The purpose of this study was to characterize clinical and ECG features of patients with painful LBBB syndrome with respect to the LBBB ECG morphology (in particular QRS axis and the precordial S/T wave ratio), clarify diagnostic criteria and possible mechanisms, and provide directions for further evaluation and treatment.

METHODS

We analyzed clinical (n = 50) and ECG (n = 15) features of patients with painful LBBB syndrome (4 patients in our practice and 46 cases identified in the literature).

RESULTS

All 15 ECGs of patients with painful LBBB syndrome had an inferior QRS axis and a very low (<1.8) precordial S/T wave ratio, which was consistent with the "new LBBB" pattern. We report a case of painful LBBB syndrome coexisting with coronary artery disease. Right ventricular apical pacing resolved intractable chest pain in 1 case of painful LBBB.

CONCLUSION

Painful LBBB ECG morphology within seconds/minutes of its onset is consistent with the new LBBB pattern with a very low (<1.8) precordial S/T wave ratio and inferior QRS axis. Painful LBBB syndrome can coexist with coronary artery disease, complicating the assessment of chest pain in the setting of LBBB. An electrophysiology study might be considered to investigate whether changing ventricular activation pattern by pacing provides consistent pain control and to select the most effective pacing configuration.