Defibrillator shocks and their impact on objective and subjective patient outcomes: results from the painfree SST clinical trial

Abstract

BACKGROUND: The impact of ICD shock on device-measured activity and patient reported outcomes is unknown.
OBJECTIVE: The purpose of this study was to analyze the acute and long-term effects of ICD shock on objective behavioral data (i.e., device-based physical activity) and subjective patient reported outcomes (e.g., quality of life and shock anxiety).
METHODS: The PainFree SST clinical trial included 2,770 patients with a single or dual-chamber ICD, or cardiac resynchronization defibrillator (CRT-D) who were followed for 22 ± 9 months. Participants completed measures of quality of life (EuroQol 5-D [EQ5D]) and shock anxiety (Florida Shock Anxiety Scale [FSAS]) at baseline, bi-annual visits, and monthly for 6 months following an ICD shock. Daily physical activity data were obtained from a built-in device accelerometer.
RESULTS: Average daily activity was 185.3 ± 119.4 minutes/day. Activity was significantly reduced after an ICD shock (p<0.0001) and recovered to a normal level after approximately 90 days. ICD shock was also associated with decreased quality of life (EQ5D Health Score) and increased EQ5D anxiety scores, but it did not impact mobility, self-care, activity, or pain. Similarly, shock anxiety (FSAS) increased in shocked patients and remained significantly elevated at 24 months, regardless of appropriate or inappropriate shock delivery.
CONCLUSIONS: ICD shocks have a long-lasting, adverse impact on both objective, device-measured physical activity and subjective patient reported outcomes of quality of life and shock anxiety. Successful management of ICD patients requires attention to clinically relevant behavioral and psychological outcomes to expedite recovery and return to activities of daily living.