Palpitations and cardiac awareness after heart transplantation

Objective: The aim of this study was to examine the awareness of resting heartbeat in heart transplantation recipients, compare it with that found in other medical populations, and determine whether clinical characteristics are associated with accurate heartbeat awareness. Methods: Eligible patients underwent a research battery consisting of a heartbeat detection task and self-report questionnaires assessing cardiac symptoms, psychosocial variables, and cognitive function. The accurate awareness of resting heartbeat was determined by presenting the patients with auditory stimuli at each of six different delays following the R wave on the EGG. Patients then selected the tones that they thought coincided with the sensation they had of their heart beating. The patients' physicians rated their cardiac morbidity. The results were contrasted with comparable data obtained in previous work with other ambulatory medical populations. Results: Forty-one consecutive heart transplantation recipients who survived for at least 3 months after surgery were eligible. Thirty-four (82.9%) of them were studied and complete data were obtained on 26 (63.4%). Nine patients (34.6%) were reliably able to detect their resting heartbeat. When compared with the 17 patients who were not accurately aware of their heartbeat, the two groups did not differ significantly in cardiac morbidity, cognitive brain dysfunction, generalized psychiatric distress, depression, somatization, or hypochondriacal attitudes. A significantly higher proportion of heart transplantation recipients were accurately aware of their heartbeat than was found in a sample of general medical outpatients and in asymptomatic, nonpatient volunteers. Conclusions: One-third of heart transplant recipients are accurately aware of resting heartbeat, despite the absence of cardiac innervation.