JAMA: Stress cardiomyopathy too narrowly defined; cardiac MRI may help
The clinical profile of stress cardiomyopathy (SC) may be broader than expected, including men, younger patients and patients without an identifiable stressful trigger. Cardiovascular MR (CMR) imaging could help rule out SC at presentation by providing helpful diagnostic information that can verify relevant functional and tissue changes, according to a study published in the July 20 issue of the Journal of the American Medical Association.

While a majority of patients diagnosed with SC, a transient form of heart failure, have similar symptoms to acute coronary syndrome (ACS), “the precise incidence of SC is unknown," Ingo Eitel, MD, of the University of Leipzig-Heart Center in Leipzig, Germany, and colleagues wrote. "But recent studies revealed a prevalence of approximately 2 percent of patients presenting with ACS in the U.S. and Europe."

With the study, Eitel et al aimed to define the clinical spectrum and evolution of SC and establish CMR criteria that would be suitable for diagnostic decision making in patients presenting with SC. To do so, Eitel and colleagues conducted a study of 256 patients with SC assessed at the time of presentation and one to six months after an acute event at seven tertiary care centers in Europe and the U.S. between January 2005 and October 2010.

The study’s primary outcome was complete recovery of left ventricular (LV) dysfunction. Of the 256 patients, 207 were postmenopausal women, 20 were women 50 or younger and 29 were men. Of the 253 patients, 239 underwent a comprehensive CMR exam.

The researchers identified a stressful trigger in 71 percent of patients. Of these cases, 30 percent were emotional stress and 41 percent were physical stress. At presentation, 88 percent of patients had symptoms that were consistent with ACS.

The researchers reported that ECGs showed abnormalities in 222 patients and that troponin T level was increased in 231 patients. Eitel and colleagues found that SC was accurately identified by CMS using specific criteria: a typical pattern of LV dysfunction, myocardial edema, absence of significant necrosis/fibrosis and markers for myocardial inflammation.

The researchers noted that follow-up CMR imaging was performed a median of three days after hospital admission and the researchers noted that these exams showed complete normalization of LV ejection fraction and inflammatory markers in the absence of significant fibrosis in all patients.

The researchers observed pleural effusion in 33 percent of patients and detected pericardial effusion in 43 percent of patients. During the study, the majority of patients were treated with cardiovascular medications for ACS (acetylsalicylic acid, clopidogrel, heparin, beta-blockers, ACE inhibitors, vasodilators and diuretics).

Four patients died during the study: two from ventricular fibrillation, one from cardiogenic shock and one from hypoxic brain injury.

The researchers wrote, “Myocardial edema, inflammation, and absence of fibrosis have been identified as potentially important markers for diffuse, reversible myocardial injury and provide unique insights into the pathogenesis and tissue pathology of this increasingly recognized syndrome.”

“Our results indicate that a broader clinical profile may be encountered in these patients,” the authors wrote. The researchers concluded that CMR imaging should be considered as a diagnostic tool for patients with SC at the time of clinical presentation.

Two-thirds of patients during the study had identifiable preceding stressors. However, previous studies have shown the percentage of emotional of physical triggers to be as high as 89 percent. “Thus, our large multicenter cohort demonstrates that the absence of an identifiable stressful event does not rule out the diagnosis, and, hence, precipitating mechanisms may be more complex, such as involvement of vascular, endocrine, and central nervous systems,” the authors wrote.

The authors said that an enhanced awareness and recognition of the clinical profile of SC will be mandatory for the correct diagnostic and treatment of these patients.

The researchers identified the following criteria for SC that will require validation in other populations:
  • Severe LV dysfunction in a noncoronary regional distribution pattern;
  • Myocardial edema colocated with the regional wall motion abnormality (edema should be verified by a quantitative SI analysis;
  • Absence of high-signal areas in LGE images; and
  • Increased early myocardial gadolinium uptake (defined by an early EGE ratio >/= 4.0).

“The exact pathophysiology of SC is still not established but is likely multifactorial, involving the vascular (abnormal vasoreactivity, endothelial andmicrovascular dysfunction), endocrine (sex differences, reduced estrogen levels), and central nervous (abnormal response to stressful events) systems,” Eitel and colleagues concluded. “The combination of typical regional wall motion abnormalities, the presence of reversible myocardial injury, and the absence of significant irreversible tissue injury may serve as a very useful set of diagnostic criteria and should be prospectively tested.”