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LIVERPOOL -- Cardiac MRI could help provide diagnostic information about potential arrhythmogenic events among patients with scleroderma being considered for implantable cardioverter defibrillators (ICDs), a researcher said here.
Among patients with significant arrhythmias seen on Holter monitoring, 73% also had positive gadolinium enhancement on cardiac MRI, compared with only 16% of patients without arrhythmias (P<0.05), according to , of the Royal Free Hospital in London.
In addition, 54% of patients with arrhythmias also had reduced ejection fraction on cardiac MRI, compared with only 4% of those without arrhythmias (P<0.05), Webber said at the
Scleroderma is a multisystem disorder predominantly affecting the microvasculature that's associated with widespread fibrosis of multiple organs, including the heart.
Cardiac problems that can develop in these patients include left ventricular systolic and diastolic dysfunction, reduced cardiac output, cardiomyopathy, and pericardial disease. Furthermore, in patients with scleroderma, including in young patients, he noted.
Around 30% are found to have supraventricular arrhythmias, and 5% to 9% have malignant ventricular tachycardia or ventricular fibrillation.
Scleroderma heart disease contributes significantly to mortality, with up to 15-20% of deaths directly related to scleroderma being cardiac in origin. Even in asymptomatic patients, autopsy studies show that up to 80% have cardiac involvement, primarily fibrosis.
"So fibrosis is the hallmark of scleroderma heart disease, but manifestations of the disease are often subclinical until they become very severe," he said.
Primary prevention of arrhythmogenic events in scleroderma patients with ICDs has been tried for some patients who have reduced ejection fraction, but the ICD device has significant risks, including the possibility of infection and increased anxiety in recipients.
"Cardiac MRI, and particularly late gadolinium enhancement, is of value in assessing the distribution and burden of fibrosis, cardiomyopathy, and ischemic heart disease, and could be a potential tool for stratifying risk and identifying patients with scleroderma who could most benefit from an ICD," he said.
Therefore, to see if cardiac MRI findings correlated with significant arrhythmias in these patients and might help predict risk, Webber's group conducted a retrospective cross-sectional analysis of data from 79 scleroderma patients who underwent the imaging study between 2000 and 2012.
Patients had been referred if they had reduced ejection fraction on echocardiography, raised troponins, or abnormalities on right heart catheterization.
Their mean age was 59, which was "very young," he commented.
Three-quarters were women, and 46% had diffuse disease. Ejection fraction was below 40% on echocardiography in 92%, and 17% had raised end diastolic pressures.
Cardiac MRI found that:
- 25% of patients had late gadolinium enhancement
- 11% had ejection fraction below 40%
- 23% had left ventricular hypertrophy
- 33% had decreased left ventricular long axis dysfunction
Individual patients had a mean of 4.2 abnormalities on cardiac MRI.
During the study period, 11 patients had significant arrhythmias. Of these, eight had late gadolinium enhancement and six had ejection fractions below 45%.
Overall, cardiac MRI had a sensitivity of 62% and a specificity of 58.6% for significant arrhythmias, Webber said.
The finding that there was a 54% difference in incidence of late gadolinium enhancement and a 50% difference in low ejection fraction between the arrhythmia and non-arrhythmias groups suggested that cardiac MRI "may therefore be of value in risk stratifying these patients when considering ICD implantation as primary prevention for sudden cardiac death," he stated.
But further work will be needed to better define the appropriate population, as cardiac MRI in this series lacked sensitivity and specificity in patients with known cardiac disease.
"We call for prospective analysis of cardiac MRI in patients with scleroderma to identify specific findings that could help clarify diagnostic and prognostic factors," Webber concluded.
From the American Heart Association:
Disclosures
The authors disclosed financial relationships with Actelion, GlaxoSmithKline, Bayer, Pfizer, and Eli Lilly.
Primary Source
British Society for Rheumatology
Source Reference: Webber M, et al "Cardiac MRI abnormalities are associated with arrhythmogenic events in systemic sclerosis: evidence for the use of the implantable cardiac defibrillator as primary prevention of sudden cardiac death" BSR 2014; Abstract O40.