Characterization of Cardiopulmonary Exercise Testing Variables in Patients with Endomyocardial Fibrosis after Endocardial Resection

Background:  Endomyocardial fibrosis (EMF) is a rare disease, characterized by diastolic dysfunction which leads to reduced peak oxygen consumption (VO₂). Cardiopulmonary exercise testing (CPET) has been proved to be a fundamental tool to identify central and peripheral alterations. However, most studies prioritize peak VO₂ as the main variable, leaving aside other important CPET variables that can specify the severity of the disease and guide the clinical treatment.

Objective:  The aim of this study was to evaluate central and peripheral limitations in symptomatic patients with EMF by different CPET variables.

Methods:  Twenty-six EMF patients (functional class III, NYHA) were compared with 15 healthy subjects (HS). Functional capacity was evaluated using CPET and diastolic and systolic functions were evaluated by echocardiography.

Results:  Age and gender were similar between EMF patients and HS. Left ventricular ejection fraction was normal in EMF patients, but decreased compared to HS. Peak heart rate, peak workload, peak VO₂, peak oxygen (O₂) pulse and peak pulmonary ventilation (V_E) were decreased in EMF compared to HS. Also, EMF patients showed increased Δ heart rate /Δ oxygen uptake and Δ oxygen uptake /Δ work rate compared to HS.

Conclusion:  Determination of the aerobic capacity by noninvasive respiratory gas exchange during incremental exercise provides additional information about the exercise tolerance in patients with EMF. The analysis of different CPET variables is necessary to help us understand more about the central and peripheral alterations cause by both diastolic dysfunction and restrictive pattern.

Keywords:
Respiratory Function Tests; Exercise Test; Cardiomyopathies; Endocardium / surgery; Cardiomyopathy, Restrictive; Breathing Exercises