The contribution of cardiopulmonary exercise testing in the familial screening for dilated and non-dilated left ventricular cardiomyopathies: case series

Background: The importance of family screening in relatives of patients affected by cardiomyopathies is highlighted in the international guidelines. Although electrocardiogram (ECG) and echocardiogram represent cornerstones of family screening, they may not always be sufficient to detect subtle abnormalities, especially in genotype-positive/phenotype-negative relatives. The role of cardiopulmonary exercise testing (CPET) in providing additional clinical information during family screening, remains to be fully elucidated. Case summary: Ten asymptomatic genotype-positive/phenotype-negative first-degree relatives of probands affected by dilated cardiomyopathy (DCM) and non-dilated left ventricular cardiomyopathy (NDLVC) were evaluated in the context of family screening. Cardiopulmonary exercise testing was integrated into the initial diagnostic evaluation. Two out of 10 relatives showed an abnormal CPET, with alteration in O2 kinetic. Discussion: Family screening in relatives of DCM and NDLVC patients, particularly in genotype-positive/phenotype-negative subjects, remains challenging due to difficulties in assessing the subtle abnormalities that may represent an initial clinical manifestation of the disease and support early treatment initiation. A more accurate and comprehensive familial screening may be achieved by integrating ECG and echocardiogram-the current first-line assessments-with data from additional tools, such as global longitudinal strain on echocardiogram, cardiac magnetic resonance, Holter ECG, and CPET.