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

Abstract

BackgroundEndomyocardial 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.ObjectiveThe aim of this study was to evaluate central and peripheral limitations in symptomatic patients with EMF by different CPET variables.MethodsTwenty-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.ResultsAge 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 (VE) 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.ConclusionDetermination 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.

Risk stratification in cardiomyopathy

“…9 In this setting, PH secondary to left ventricular dysfunction is frequent and is a consolidated predictor of mortality 27 623 VE/VCO 2 slope >31 was the only CPET variable to be independently associated with SCD Finocchiaro et al 28 156 Peak exercise cardiac output is the primary determinant in exercise tolerance: a peak VO 2 <20 ml/kg/min or <80% of predicted was associated with worse prognosis; indices of ventilatory inefficiency are only weakly associated with diastolic parameters A VE/VCO 2 slope >34 and left atrial dimension emerged as main predictors of overall mortality, HTx, deterioration to septal reduction Coats et al 29 1898 Independent relationship between peak VO 2 and VE/VCO 2 slope and death from HF: the reduction of 21% in the risk of death/ HTx for each 1 ml/kg/min increase in peak VO 2 and by 29% for each 1 ml/kg/min increase in AT. The risk of death/HTx is increased by 18% for each unit increase in VE/VCO 2 slope Magrì et al 30 81 pHR (peak HR) < 70% was correlated with HF-related events Magrì et al 15 681 Peak HR was a prognostic factor for HF-related events and SCD ARVC/D Scheel et al 24 38 Safety and prognostic capability of CPET Maximal exercise effort had not achieved in about a quarter of them VE/VCO 2 slope was the main prognostic predictor RCM Sayegh et al 19 26 Normal VE/VCO 2 slope Reduced peak workload, VO 2 , O 2 pulse, VCO 2 , VE Sayegh et al 20 15 Peak VO 2 similar between RCM and DCM, both less than HS ARVC/D: arrhythmogenic right ventricle cardimoyopathy/dysplasia; AT: anaerobic threshold; CMPs: cardiomyopathies; CPET: cardiopulmonary exercise testing; CVD: cardiovascular disease; DCM: dilated cardiomyopathy; HS: healthy subjects; HTx: heart transplantation; mPAP: mean pulmonary artery pressure; HCM: hypertrophic cardiomyopathy; HF: heart failure; HR: heart rate; PH: pulmonary hypertension; SBP: systolic blood pressure; SCD: sudden cardiac death; VO 2 : oxygen uptake; VE: ventilation; VCO 2 : carbon dioxide consumption; VE/VCO 2 : ventilation/carbon dioxide consumption.…”

“…Sayegh et al. 19 conducted CPET on 26 patients with endomyocardial fibrosis: they were mostly women, with pure diastolic dysfunction. The authors demonstrated a normal VE/VCO 2 slope and respiratory exchange ratio achievement.…”

Challenges in addressing the knowledge gap on endomyocardial fibrosis through community-based studies

“…This is clearly shown by the relatively small number of EMF publications on PubMed-considering its high morbidity and poor outcomes-since its description in 1948 (20). Table 1 shows EMF studies published on PubMed in the last 5 years using the word "endomyocardial fibrosis" and excluding case reports and articles that do not refer to the characteristic tropical EMF accessed on 1 st June 2019 (21)(22)(23)(24)(25)(26)(27).…”