Case Report: Integrated cardiovascular and respiratory training as a novel therapeutic approach in a case of painful left bundle branch block

Background Left bundle branch block (LBBB) is a heart rate (HR)–dependent cardiac conduction disorder that may occur in the absence of structural heart disease and can be associated with painful episodes. Evidence supporting exercise-based interventions in this setting is limited. We report the case of a 41-year-old woman with paroxysmal, painful LBBB, with onset occurring marginally above resting HR. Methods After a diagnostic evaluation demonstrating preserved biventricular function, absence of myocardial ischemia, and normal hemodynamic responses, a 10-month supervised training program was implemented in three sequential phases: (1) diaphragmatic breathing exercise; (2) aerobic exercise performed below the individual LBBB HR threshold; (3) interval and steady-state aerobic exercise prescribed according to individually determined ventilatory thresholds (VT1 and VT2). Resting HR, HR at LBBB onset, maximal oxygen consumption (V˙O 2 max), ventilatory thresholds, and their associated HRs were longitudinally assessed. Results After training, resting HR decreased by 15 bpm, while HR at LBBB onset increased by 50 bpm, markedly expanding the safe exertional window. V˙O 2 max improved progressively, together with upward shifts in VT1 and VT2, and reductions in corresponding HRs. Importantly, the patient reported resolution of LBBB-related pain during daily activities and even when LBBB was occasionally elicited at higher exercise intensities. Conclusions This case suggests that a tailored respiratory and aerobic training program may safely improve cardiovascular efficiency, functional capacity, and symptom control in a patient with painful, HR-dependent LBBB. Individualized exercise training may represent a non-invasive adjunct or alternative to pharmacological or pacing strategies in selected patients.