Background. Primary and secondary prevention trials have shown that implantable cardioverter-defibrillators (ICD) reduce the risk of cardiac death, but concerns have been raised regarding the psychological well-being of ICD patients. Anxiety can affect a significant proportion of these patients, but there is limited information about prevalence and determinants of anxiety after the implementation of the more recent guidelines for ICD implantation. Several behavioral interventions have been effective in improving anxiety in these patients, however the efficacy of mindfulness-based interventions (MBI) has not been investigated in ICD patients, and there is limited information regarding the characteristics of pre-intervention, “dispositional” mindfulness in patients with cardiovascular disease never exposed to mindfulness training. The aims of this dissertation project were: 1) To determine the feasibility of a randomized clinical trial of a phone-administered, mindfulness-based training program, as measured by recruitment and retention rates, treatment adherence and fidelity; 2) To evaluate the current baseline prevalence and determinants of anxiety in the study population and 3) To describe the correlates of dispositional mindfulness in the study population.
Methods. The study was conducted at the Electrophysiology Service at the UMass Memorial Medical Center. All consecutive patients who recently underwent an ICD procedure or received ICD shocks were screened for eligibility to participate in a pilot randomized controlled trial in which an eight session, phone-delivered, weekly MBI was compared to a usual care condition. Assessments were performed at baseline and post-intervention. A cross-sectional design was used for aims 2 and 3. Anxiety was assessed using the Hospital Anxiety and Depression Scale; a shortened version of the Five Facets of Mindfulness questionnaire was used to evaluate mindfulness.
Results. Thirty patients (21 M, 9 F; mean age 63.1 ±10.3 years) were enrolled in the study. The methods ultimately adopted to screen, recruit, and retain study participants were feasible to conduct and satisfactory to ICD outpatients, and the study intervention was safe. Phone delivery resulted in excellent retention rates and limited costs. Assessments of treatment fidelity showed that the content of the intervention was delivered as intended in almost 100% of cases.
The study findings do not show a decrease in the overall prevalence of anxiety in ICD patients compared with earlier cohorts; anxiety was associated with young age, low socio-economic status and previous psychological morbidity, but not with ICD-related factors including prior shock delivery.
Finally, baseline mindfulness was most strongly associated with previous psychological morbidity (in particular, depression), and current anxiety symptoms.
Conclusion. Psychological morbidity appears to be the major determinant of anxiety in the patients currently enrolled in the study. Dispositional mindfulness is inversely associated with current anxiety and depression and with prior psychological morbidity, supporting the hypothesis of a modulating role of mindfulness on the processing of negative emotions. A phone-delivered, individual MBI is feasible, acceptable to patients and can be adequately delivered by trained instructors. The findings from this dissertation work support the need for larger clinical trials of MBI in ICD patients
