Safety of cardiopulmonary exercise testing in a large contemporary cohort of adults with congenital heart disease: implications on levels of test supervision

Abstract

Abstract Background Exercise intolerance is common in adults with congenital heart disease (ACHD). Cardiopulmonary exercise testing (CPET) is used routinely as an objective assessment of the exercise capacity, the severity and mechanisms of exercise intolerance, and the effect of intervention. Little is known on the safety of CPET in ACHD, resulting in the American Heart Association recommending physician supervision of all patients with intracardiac shunts. Purpose To assess the safety of CPET in ACHD. Methods We retrospectively examined 9309 CPETs performed on ACHD patients in a tertiary referral Centre over 20 years to document major or minor events. All tests were performed in-hospital, with an emergency alarm system on site, and supervised routinely by 2 clinical exercise physiologists. Major events were classified as death within 48 hours and cardiac arrest, syncope, sustained/symptomatic ventricular tachycardia (VT) and sustained/symptomatic supraventricular tachycardia (SVT) during the test. Minor events were classified as non-sustained/asymptomatic VT, non-sustained/asymptomatic SVT, bradyarrhythmia, chest pain and significant ST segment ECG changes, new onset of left or right bundle branch block). Results During the study period, 9309 CPETs were performed on 4941 ACHD patients (age 33.0±14.7 years, 52.3% male), of varying complexity by Bethesda classification (18.3% simple, 51.2% moderate, 27.4% great) Figure 1. A major event occurred in 56 (0.6%) tests and a minor event in 870 (9.3%) tests. There were no deaths within 48 hours, nor cardiac arrests during the test. There were 6 (0.1%) cases of sustained or symptomatic VT, 4 (<0.1%) syncopal episodes and 46 (0.5%) instances of sustained or symptomatic SVT. A total of 31 (0.3%) episodes of bradyarrhythmia, 377 (4%) significant ECG changes and 267 (2.8%) episodes of chest pain were recorded. Moreover, there were 107 (1.2%) cases of non-sustained or asymptomatic VT and 88 (1%) cases of non-sustained or asymptomatic SVT. Patient fatigue (3701, 40%), shortness of breath (2246, 24.1%) and leg discomfort (1286, 13.8%) were common reasons for stopping the test, whereas only 95 (1%) tests were stopped due to chest pain. Conclusions Our data on a large ACHD population undergoing CPET demonstrate a potential risk for arrhythmic complications during exercise and recovery, mostly due to sustained or symptomatic SVT, while the risk of all the other major cardiovascular events is low. Our data support the use of CPET in routine ACHD practice, with quick recognition and management of potential adverse events in a controlled environment by appropriately trained cardiac physiologists.