PTSD symptoms more than double mortality risk in patients with ICDs

Caroline Cassels

November 07, 2008

Munich,Germany- Individuals who receive implantable cardiac defibrillators (ICDs) after a sudden cardiac event are more than twice as likely to die within five years if they experience symptoms of posttraumatic stress disorder (PTSD), regardless of disease severity [1].

In a prospective cohort study, researchers from the Technische Universität München in Germany found that PTSD symptoms in this patient population were associated with a 2.4-fold increased mortality risk.

"We were struck by the finding that patients suffering from PTSD symptoms had a substantially higher risk of mortality, and it was particularly striking that this association was strengthened after adjustment for known risk factors. This study shows there is direct evidence that PTSD independently influences mortality risk," said principal investigator Dr Karl-Heinz Ladwig.

The study was published in the November 2008 issue of Archives of General Psychiatry.

PTSD generally overlooked

According to Ladwig, PTSD is often overlooked in cardiac patients. Although it is generally recognized that ICD patients should undergo psychological screening and possible treatment as part of their follow-up care, this does not always translate into clinical practice. "In part, this may have to do with the patients themselves, many of whom are resistant to this type of care and are intent on coping by themselves, but there is no doubt that they need help," said Ladwig.

It is estimated that between 8% and 20% of patients with acute coronary syndromes and 27% to 38% of those who survive a cardiac arrest develop PTSD. The authors point out that a significant proportion of patients with an ICD have survived a cardiac arrest or an acute MI, which can cause acute psychological distress. Treatment with an ICD, although highly effective and lifesaving, could further contribute to psychological distress by serving as a constant reminder of the underlying disease.

Recent research from the Veterans Affairs Normative Aging Study linked PTSD symptoms and coronary heart disease in a cohort of apparently healthy men. However, the researchers note, little is known about the effect of PTSD on patients with ICDs.

Impact on prognosis

To determine the impact of PTSD on long-term mortality, investigators followed 211 patients with ICDs who routinely attended a cardiac outpatient clinic after a cardiac event in 1998. The study's primary outcome was mortality risk per 1000 person-years.

Participants were surveyed an average of 27 months after implantation, and at that time 38 reported severe PTSD symptoms and 109 reported low or moderate PTSD symptoms. During an average of 5.1 years, 45 (30.6%) of the patients died: 32 of 109 patients with low or moderate symptoms and 13 of 38 with high levels of symptoms.

In their adjusted analyses, which controlled for age, sex, diabetes mellitus, measures of cardiac disease, and comorbid anxiety and depression, the researchers found that PTSD symptoms substantially increased mortality risk.

Compared with 55 fatal events per 1000 person-years in patients without PTSD, the long-term absolute mortality risk accounted for 80 fatal events per 1000 person-years in patients with PTSD, the authors report. In addition to increased mortality risk, patients with PTSD reported more cardiac symptoms, including chest pain. However, clinical characteristics that typically account for survival differences in such patients did not differ between the two groups.

"Therefore, the perceived severity rather than the objective severity of a cardiac condition, as determined by cardiac criteria, may be associated with PTSD," the authors write.

According to Ladwig, more research is needed to assess the behavioral and biologic pathways by which PTSD contributes to excess mortality risk in patients with ICDs.

Psychological disorders common in heart patients

Asked to comment on the study, Dr William T Abraham (Ohio State University Medical Center, Columbus), highlighted the need for high-quality psychological support.

Abraham pointed out that psychological disorders are common in patients with cardiovascular disease. At least 50% of heart-failure patients are clinically depressed at some point in the natural history of their disease.

Depression in this setting and in the setting of other cardiovascular disorders, including ischemic heart disease and arrhythmias, said Abraham, is associated with worse outcomes. He also pointed out there is a pathophysiologic basis for this.

"Depression is associated with an increase in inflammatory mediators and other substances that may contribute to disease progression. PTSD is a little different and not uncommon following ICD shocks. However, the physiological effects of PTSD may be similar to those seen with depression. In its extreme form, shock-induced PTSD may lead some patients to ask that their ICDs be turned off. I have seen this more than a few times over the years. Counseling and support groups are very important in treating these patients," he said.

The study was supported by the Deutsche Forschungsgemeinschaft and an unrestricted educational grant from Boston Scientific Guidant. Ladwig reports receiving lecture fees from Medtronic.

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