Development of a measure of the concerns held by people with implanted cardioverter defibrillators: the ICDC

To develop a questionnaire to measure the extent and severity of the concerns of people with an implanted cardioverter defibrillator.

Items were generated from patient interviews, expert review and the research literature on patients' worries and concerns. A pilot version was administered to a series of ICD patients and repeated for test-retest reliability 6 weeks later. Psychometric tests including the screen test, factor analysis and various reliability assessments were undertaken. It was predicted that the greater the extent and severity of concerns, the greater the anxiety experienced by the ICD patient. Scores were compared with a validated measure of anxiety and depression administered at the same time.

Fifty-seven (64%) patients completed and returned the questionnaire and a further 22 (100% of those asked) completed the 6-week retest. Reliability and validity appeared to be good and two factors were identified. Both total score and the individual factor scores correlated moderately with anxiety.

The questionnaire appears to reflect patients' concerns and, as predicted, these were associated with the patients' anxiety level. The scale requires further testing to reveal if it is of use both clinically and for research purposes.