Abstract 13812: Feasibility and Compliance with Daily Home ECG Monitoring of the QT Interval in Heart Transplant Recipients
Recent evidence suggests that acute allograft rejection following heart transplantation causes an increased QT interval on the ECG. No prospective study has investigated whether increases in the QT interval might represent a new noninvasive biomarker for early detection of acute allograft rejection. The aims of this pilot study were to: (1) determine whether heart transplant patients could achieve compliance in transmitting a 30-second ECG every day for 1 month using a simple ECG device and their home telephone, (2) evaluate ease of device use and acceptability of time required for transmission by transplant recipients, and (3) evaluate quality of transmitted ECG tracings for QT interval measurement.
Methods: A convenience sample of adult heart transplant patients were recruited and trained to use the device (HeartOne, Aerotel, Israel). Lead II was used with electrodes that were easy to slip on and off (expandable metal wrist watch-type electrode for right wrist and C-shaped band electrode for left ankle). Patients used a toll-free number with automated voice prompts to guide their ECG transmission to the ECG Monitoring Research Lab at UCSF for analysis.
Results: 32 subjects (72% male; mean age 52 ±17; 37% non-White) achieved an ECG transmission compliance of 73.4% (daily) and 100% (weekly). When asked, How difficult do you think it was to record and transmit your ECG by phone, 90% of subjects replied either “somewhat easy” or “extremely easy.” Subjects reported that recording their ECG using the HeartOne device was easy but that transmitting their ECG by telephone was more difficult and time-consuming. Of the total 548 ECGs that were transmitted by subjects, 384 (70.1%) were acceptable quality for QT interval measurement. Mean QTc was 415 ±31 ms, males; 426 ±40 ms, females. 14 subjects (43.8%) had an extremity tremor and 19 subjects (59.4%) had ≥1+ left leg edema. Neither of these conditions was associated with a poor quality ECG.
Conclusion: Transplant subjects are compliant with recording/transmitting daily and weekly ECGs. Ankle edema and side effects of immunosuppressive drugs that cause tremor are common but do not interfere with ECG quality. Direct internet transmission rather than telephone modem transmission should be explored for future clinical trials.
- © 2010 by American Heart Association, Inc.