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˙O2max), 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˙O2max 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.