Changes in Cardiopulmonary Exercise Testing in Patients Undergoing Cardiac Resynchronization Therapy

Abstract

1474 PURPOSE: A common problem in patients with chronic congestive heart failure (CHF) is the electromechanical anomalies that result from atria-ventricular and intra-ventricular conduction (IVCD). Cardiac Resynchronization Therapy (CRT) is a recently described technique that aims at correcting the problem. Several studies have demonstrated that CRT enhanced the quality of life and the exercise capacity of such patients. The aim of the study was to show the preliminary results of cardiopulmonary exercise tests performed on 20 points. METHODS: Subjects were 20 patients (13 males and 7 females, mean age = 58.9 ± 10.6). All patients were in chronic CHF (18 in class III – IV of NYHA) despite full medical therapy. All patients had IVCD (GRS > 140ms) and compromised left ventricular function (mean 25%). Graded exercise treadmill test with gas exchange measurement was performed using a modified Naughton protocol before and 6 months following implantation of In-Sync biventricular pacemaker. Ten patients (6 males and 4 females) have done the per and post tests. All subjects signed an informed consent form prior to the tests. RESULTS: The following table summarizes the results of percentage change in post-pacemaker compared to pre implantation for 10 patients.TableVO2 = oxygen uptake, HR = heart rate;O2 pulse = oxygen pulse; VE = minute ventilation; RF = respiratory frequency; Vt = tidal volume: RQ = respiratory quotient. Note: Females are patients 1 to 4; Males are patients 5 to 10. CONCLUSIONS: Cardiorespiratory response to graded exercise test in all CRT patients revealed improvements with varying percentage level. This may have significant impact on the quality of the patient's daily lifestyle.