Six-minute walk test in patients with permanent cardiac pacemakers

The 6-minute walk test (6MWT) is a simple and reliable method routinely used in the evaluation of many conditions including cardiac diseases. However, it is rarely performed in patients with pacemakers (PMs), and the applicability and safety in this group is not established. The purpose of this study was to verify the applicability and safety of the 6MWT in the evaluation of functional capacity of patients with PMs, considering the ergometry test (ET) as the criterion standard.

Twenty-four patients with rate-responsive PMs underwent a treadmill ET, using the Chronotropic Assessment Exercise Protocol, and a 6MWT, performed twice with a rest interval of 20 minutes. Functional capacity, heart rate, and blood pressure in each test were recorded.

The distance covered during the 6MWT significantly correlated with the oxygen uptake estimated from the treadmill ET (r = 0.709, P < .001). Peak heart rates and systolic blood pressure levels reached during the 2 tests were also significantly correlated. No adverse events or malignant arrhythmias were observed during the 6MWT. The distance walked during the 6MWT accurately predicted the patient performance on the ET (area under the receiver operating characteristic curve = 0.921). The ability to walk more than 538 m in the 6MWT predicted, with a sensitivity of 90% and a specificity of 79%, an estimated oxygen uptake above 10 metabolic equivalents (METs) on the ET.

The 6MWT can be considered safe to assess the submaximal functional capacity and can be used as an alternative test to evaluate the results of interventions in patients with permanent cardiac PMs.