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Myocardial Impairments Rather Than Rhythm Status Contributes to Exercise Intolerance in Patients with Atrial Fibrillation
Author(s) -
Elliott Adrian,
Verdicchio Christian,
Gallagher Celine,
Linz Dominik,
Mahajan Rajiv,
Sanders Prashanthan
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.lb339
Subject(s) - medicine , exercise intolerance , cardiology , atrial fibrillation , sinus rhythm , cardioversion , ejection fraction , cohort , heart failure , treadmill , chronotropic , heart rate , blood pressure
Background Exercise intolerance is commonly reported in patients with atrial fibrillation (AF) despite preserved ejection fraction. However, the contribution of rhythm, echocardiographic parameters and cardiovascular risk factors to exercise intolerance is poorly understood. Furthermore, recent data shows a high prevalence of heart failure with preserved ejection fraction amongst AF patients, which may contribute to exercise intolerance. Our aim was to evaluate the prevalence of exercise intolerance and its potential contributors amongst a cohort of AF patients undergoing cardiopulmonary exercise testing (CPET). Methods We assessed 151 AF patients (34% female) referred for CPET. All patients underwent routine clinical assessment, including detailed evaluation of cardiovascular risk factors, transthoracic echocardiography and a maximal CPET using a modified Balke treadmill protocol. To investigate the contribute of cardiac rhythm to exercise tolerance, CPET was reported in a select cohort of patients with persistent AF, 21 days following electrical cardioversion to sinus rhythm (SR). Results The mean age was 67±8 years with a BMI of 29.4±4.4 Kg/m 2 . 59% of the cohort were in sinus rhythm (SR) at the time of testing. 41% of patients reached a peak VO 2 <85% of age and gender predicted values. There was no significant difference in peak VO 2 between patients in AF versus SR (p=0.22). After adjustment for age and gender, only chronotropic response (p=0.017) and echocardiographic indices of left ventricular (LV) filling pressures (E/E′, p=0.014) were significant predictors of peak VO 2 . In 20 patients who underwent subsequent cardioversion from AF to SR, peak VO 2 improved significantly from 19.7±7.0 to 21.4±6.1 ml/kg/min (p=0.003). Conclusion Our main findings are that (i) the main predictors of peak VO 2 are chronotropic response to exercise and indices of LV filling pressure, (ii) peak VO 2 can be significantly improved in patients with persistent AF by restoration of SR. These findings highlight potential targets alongside rhythm control, for the improvement of exercise tolerance in AF patients. Support or Funding Information National Heart Foundation of Australia Postdoctoral Fellowship This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .