Impact of Extravalvular Remodeling on Wearable Smartwatch‐Recorded Physical Activity in Patients Undergoing Transcatheter Aortic Valve Implantation for Severe Symptomatic Aortic Stenosis

Background: Wearable smartwatches enable objective quantification of physical activity. This study evaluated the association of extravalvular cardiac damage in aortic stenosis with smartwatch‐recorded physical activity before and after transcatheter aortic valve implantation (TAVI). Methods: Patients with severe symptomatic aortic stenosis were dichotomized into cardiac damage stages 0 to 2 (left‐heart dysfunction) and stages 3 to 4 (pulmonary/right‐heart dysfunction) by echocardiography. All patients received a Fitbit smartwatch for 7 days of continuous monitoring before transcatheter aortic valve implantation and at 6‐month follow‐up. Regression models determined significant predictors of total daily step count and moderate to vigorous physical activity (MVPA). Results: Within the study cohort (stages 0–2: 43 [50.6%]; stages 3–4: 42 [49.4%]), all patients showed significant improvement in physical activity from baseline to follow‐up (all P <0.001). Patients in stages 3 to 4 had significantly lower total daily step count and MVPA at baseline and follow‐up, as well as a smaller improvement in MVPA (all P <0.05). Relative to stages 0 to 2, stages 3 to 4 were significantly associated with lower step count and MVPA at baseline (step count: β=−1453.8 [95% CI, −2351.3 to −554.2], P =0.002; MVPA: β=−12.9 [95% CI, −24.3 to −1.5], P =0.027) and follow‐up (step count: β=−1438.1 [95% CI, −2453.9 to −422.3], P =0.006; MVPA: β=−27.4 [95% CI, −47.7 to −7.1], P =0.009), as well as less improvement in MVPA (β=−14.5 [95% CI, −28.4 to −0.48], P =0.043) after transcatheter aortic valve implantation. Conclusions: The extent of cardiac damage before transcatheter aortic valve implantation has an important impact on physical activity, both at baseline and following intervention. Future studies should examine whether smartwatch‐measured activity predicts death across cardiac damage stages and whether cardiac rehabilitation improves outcomes in aortic stenosis with advanced remodeling.