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Non-ischemic dilated cardiomyopathies (DCM) are important causes of heart transplant worldwide. Previous international data suggest that familial etiology for heart failure may be frequently overlooked among patients undergoing heart transplant. A structured screening instrument may help to identify patients who would benefit from genetic testing. Fifty-nine heart transplanted patients from a single transplant center in South of Brazil were reviewed between 2015-2019; those with hypertrophic cardiomyopathies or confirmed ischemic DCM were excluded. Patients with non-ischemic CMP answered a structured screening questionnaire (Kushner et al., 2006), and familial etiology was classified in confirmed, probable, possible familial or non-familial DCM. Thirty-four heart transplant recipients were included (53% male, 85% Caucacian, 50±14 years). Etiologic classification pre and post structured screening is depicted in Figures 1A and 1B. There was a difference in suspected familial etiology pre and post structured screening (15% versus 32%; p = 0.037). These findings suggest that familial DCM is frequently overlooked by the time of heart transplant. Our prevalence of familial DCM is similar to international reports. Applying a structured, low-cost, screening tool may contribute to counseling patients and their relatives regarding special attention to cardiovascular conditions and proper indication of genetic testing in a resource-limited scenario. [ABSTRACT FROM AUTHOR]

Introduction Exercise-induced left bundle branch block (LBBB) is rarely observed in exercise testing, and usually implies a worse prognosis. Cardiac resynchronization therapy (CRT) is well validated in patients with heart failure with reduced ejection fraction (HFrEF) and LBBB. Although the indications of CRT do not include exercise-induced LBBB, the functional impairment secondary to dynamic electromechanical dyssynchrony could potentially be improved with CRT. Case Report A 57-year-old woman with long-standing idiopathic dilated cardiomyopathy (ejection fraction of 23%) presented with clinical deterioration to NYHA functional class 4 and recurrent hospitalizations despite optimal medical treatment. During evaluation for cardiac transplant, new-onset of intermittent LBBB was observed on the cardiopulmonary exercise test (her resting QRS duration was 100ms). A stress echocardiography showed exertion-induced intraventricular and interventricular dyssynchrony. Cardiac resynchronization therapy was then indicated, and 97% resynchronization rate was obtained. There was clinical improvement to NYHA class 2 and no hospitalizations since the CRT initiation. Functional reassessment at 6 and 12 months post-implant demonstrated significant improvement in prognostic exercise parameters (Figure). She currently remains off the transplant list. Summary In HFrEF patients with no LBBB at rest, exercise test and stress echocardiography may uncover dynamic electromechanical dyssynchrony that may benefit from CRT. This is the first report of CRT for treatment of an advanced heart failure patient with worsening symptoms attributed to exercise-induced LBBB. [ABSTRACT FROM AUTHOR]