HEART BEAT DETECTION AND CARDIOVASCULAR REACTIVITY OF PATIENTS WITH FUNCTIONAL CARDIAC DISORDER

Cardiac complaints without somatic origin are labeled as ''functional' by internists or cardiologists. In recent years, this disorder has partly or completely been identified with panic disorder. The somatic complaints of the patients mainly consist of bodily sensations. This is one reason why interoceptive processes of the patients are of importance. The present investigation addresses two main questions: 1 . Is the interception of patients with functional cardiac disorder more sensitive than that of healthy controls? 2. Can a classification of the patients in terms of cardiovascular reactivity be replicated. Twenty-one patients and twenty healthy controls participated in the experiment. A method of 'heart beat detection'', which provided the subjects with exteroceptive signals, which were either in synchronization with their heart beats or not, was used. This difference had to be detected by the subjects during two blocks of 40 trials. After this part of the experiment the patients underwent two stress conditions. First in a modified Sidman avoidance task, they had to avoid loud acoustic stimuli by detecting the correct time interval for the avoidance response. The second condition consisted of viewing a video film, showing the unsuccessful resuscitation of a person. In the interception task, the patients performed less well compared to the healthy controls. With regard to their cardiovascular reactivity in the stress conditions, patients could be classified into two subsets. Patients showing larger differences in heart rate between rest and stressful periods of the experiment also showed superior heart heat detection.