Comparison of Cardiovascular Responses to Isometric (Static) and Isotonic (Dynamic) Exercise Tests in Chronic Atrial Fibrillation

The aim of the present study was to evaluate the tolerance to various exercises by determining the cardiovascular response to static and dynamic exercises in patients with nonvalvular atrial fibrillation. Fifty patients (mean age: 63.6 +/- 10.3 years; male: 25, female: 25) with chronic (more than one year) nonvalvular atrial fibrillation were included in the study. All patients underwent exercise tests, adjusted appropriately according to their symptoms, as dynamic exercise on a Marquette Case 15 device according to a modified Bruce protocol. Heart rate, and systolic and diastolic arterial pressures were measured at rest and at all stages of the exercise; and the heart rate-pressure products were evaluated. A handgrip test was also conducted as static exercise. The measurements were made before, at the 1st, 2nd and 3rd minutes, and in the recovery periods of the exercise. The percent values of the changes of the 1st, 2nd and 3rd minute measurements in relation to the initial values for both exercises were compared. In addition, the maximal responses to the exercise tests and the post exercise values were also compared. For statistical evaluations, the paired Student-t test was used. Heart rate and pressure-heart rate product values obtained at 1, 2, and 3 minutes during the treadmill exercise test were significantly high compared to the handgrip values (P < 0.0001). The arterial systolic and diastolic pressure values in the 1st minute were also significantly higher during the handgrip test (P = 0.0100 and P = 0.0320, respectively). The values of diastolic arterial pressure at the 2nd minute during the handgrip test, and systolic arterial pressure at the 3rd minute during the treadmill test were found to be statistically significant (P = 0.0240, P = 0.0340, respectively). The mean exercise time and MET value during the treadmill exercise test were 7.18 +/- 2.65 minutes and 5.32 +/- 1.38 mL.kg(-1) x dk(-1). respectively. During the recovery period, the 5th minute, heart rate and pressure-heart rate product values were significantly high after the treadmill test (P < 0.0001). In this study, we revealed that the heart rate response to static exercise was lower and the patients tolerated the static exercise better. Therefore, we decided that the short duration of static exercise is not harmful for the noncomplicated chronic atrial fibrillation cases.