Ascending thoracic Aortic Wall stress response during aerobic, resistance and isometric exercise in patients with arrhythmogenic cardiomyopathy

BACKGROUND: While moderate-intensity endurance exercise is recommended in patients with and without dilated aorta, little is known about aortic physiology during isometric and resistance exercise. METHODS: We analyzed 18 individuals with arrhythmogenic cardiomyopathy (ACM) without valvular or aortic pathology (mean age: 43 ± 9 years). Patients underwent computer tomography of the aorta and invasive exercise right heart catheterization during moderate intensity endurance, isometric and resistance exercise: Isometric handgrip (HG) and bicep curl (BC) were performed for one minute at 70% of maximal voluntary contraction and compared to continuous supine cycle exercise at the first ventilatory threshold for twenty minutes. Circumferential ascending aortic wall stress (AWS) was calculated during these three exercise modalities using the Laplace Law incorporating resting diameter and thickness of the ascending aorta as well as systolic blood pressure values obtained at rest and during exercise. RESULTS: The mean aortic diameter and thickness were 29 ± 5 mm and 1.7 ± 0.3 mm. Systolic and diastolic blood pressure, heart rate, and AWS all significantly increased from rest across the three exercise modes. No difference in AWS was found between exercise modes. Diastolic blood pressure during cycle exercise was significantly lower than during isometric HG. Also, heart rate during cycle exercise was significantly higher than during both BC and isometric HG exercises. CONCLUSION: All exercise modes resulted in a similar increase in AWS in ACM patients. Although these findings appear to be reassuring, the long-term implications of chronic exposure to moderate-intensity resistance exercise remain to be determined.