Psychosocial therapy reduced the risk of cardiovascular death at 2 years after "out of hospital" sudden cardiac arrest

Cowan MJ, Pike KC, Budzynski HK. Psychosocial nursing therapy following sudden cardiac arrest: impact on two-year survival.Nurs Res 2001 Mar-Apr;50:68–76[Medline]

QUESTION: In patients who have survived "out of hospital" sudden cardiac arrest, does psychosocial therapy reduce cardiovascular mortality at 2 years?

Randomised {allocation concealed ^*}, partially blinded (outcome assessor)^*, controlled trial with 2 years of follow up.

A nursing school clinic in the US.

133 patients (73% men) who had survived "out of hospital" ventricular fibrillation or asystole (confirmed by electrocardiography). Exclusion criteria included coronary artery bypass surgery or other vascular procedures in the previous 6 months, diabetes, moderate to severe anoxic encephalopathy, and other life threatening comorbid conditions. More than 96% of patients completed the treatment period, and the mortality status of 97% of patients was known at 2 years.

After stratification by sex, patients were allocated to 11 individual 90 minute sessions of psychosocial therapy (n=67) or usual care (n=66). Psychosocial therapy was given by 1 of 2 cardiovascular nurses and consisted of (1) physiological relaxation with computerised feedback training focused on altering autonomic tone; (2) cognitive behavioural therapy for improving self management and coping strategies for depression, anxiety, and anger; and (3) health education about cardiovascular risk factors. The usual care group also received a health education class about cardiovascular risk factor modification.

Cardiovascular mortality (death from arrhythmia, stroke, myocardial infarction, or congestive heart failure). Secondary outcomes included all cause mortality.

By 2 years, 3 patients in the psychosocial group had died (1 cardiovascular death) and 8 in the usual care group died (7 cardiovascular deaths). The risk of cardiovascular death was lower in the psychosocial therapy group than in the usual care group (p=0.03) (table). The risk reduction remained statistically significant after adjusting for other predictors of mortality: depression, hypertension, previous myocardial infarction, low heart rate variability, congestive heart failure, and ventricular ectopic beats (>10 beats/h on Holter monitor). The groups did not differ for all cause mortality at 2 years.

View this table: [in this window] [in a new window]   Psychosocial therapy v usual care for patients who survived "out of hospital" sudden cardiac arrest

 

In patients who had survived "out of hospital" sudden cardiac arrest, psychosocial therapy reduced the risk of cardiovascular death at 2 years.

Source of funding: National Institute of Nursing Research.

For correspondence: Dr M J Cowan, School of Nursing, University of California Los Angeles, Factor Building 2-256, Box 951702, Los Angeles, CA 90095-1702, USA. Fax +1 310 206 7433.

^* See glossary.

Information provided by author.

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Commentary

Lawrence A Palinkas, PhD

University of California, San Diego La Jolla, California, USA

Psychosocial therapy has long been considered to be a potentially valuable tool in providing quality care to patients with coronary artery disease (CAD) in the aftermath of a myocardial infarction. The study by Cowan et al provides further evidence of this value, one that persists 2 years after an "out of hospital" sudden cardiac arrest. Although previous study findings suggest the benefits of cognitive behavioural therapies in reducing cardiovascular death,¹ this study is noteworthy in reporting an 86% risk reduction in 129 patients, a reduction that persisted after controlling for important confounders.

It is unclear, however, why psychosocial therapy is so effective in reducing cardiovascular death in these patients. The overwhelming evidence is that such patients often experience depression, anxiety, and anger. Although negative mood may seem an inevitable consequence of CAD, it may also precipitate sudden cardiac arrest. The authors also make a good case for the use of biofeedback to restore autonomic nervous function and increase heart rate variability (HRV).

This study fails to indicate, however, which of the 3 components, if any, contributed to the success of this intervention. No statistically significant changes were observed in HRV (except in patients with low baseline levels) or mood (except for a marginal effect on depression). The reduction in breathing rate disappeared at 6 months. Hence, no clear evidence exists of a causal mechanism involving either physiological relaxation or cognitive behavioural therapy.

Perhaps the answer lies in the increased attention given to the 67 patients in the intervention group of this study. These patients attended 11 individual sessions over a 5–6 week period, each session lasting 90 minutes. In contrast, no information is provided on the content of the "conventional treatment" of the 66 control patients and whether this treatment included a comparable level of attention or involvement with healthcare personnel. The increased interaction between patients and nursing staff may have contributed more to the dramatic reduction in cardiovascular death than the context of this interaction (ie, the psychosocial therapy), a phenomenon known as the Hawthorne Effect.

1. Linden W, Stossel C, Maurice J. Psychosocial interventions for patients with coronary artery disease: a meta-analysis. Arch Intern Med 1996;156:745–52.[Abstract/Free Full Text]

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