Five diagnostic tests were determined to provide the most accurate diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), which led investigators to suggest a need to revise the criteria used to evaluate the presence the disease, according to a study in the July edition of the Heart Rhythm Journal.
From 2001 to 2008, the North American Multidisciplinary Study, led by Frank Marcus, MD, a cardiologist at the University of Arizona, enrolled 108 newly diagnosed patients with suspected ARVC/D in 18 centers throughout the U.S. and Canada.
ARVC/D is a genetic cardiomyopathy characterized by ventricular arrhythmias and structural abnormalities of the right ventricle. In ARVC/D, there is a progressive replacement of right ventricular myocardium with fatty and fibrous tissue and ventricular arrhythmias of right ventricular origin. The precise prevalence of ARVC/D is relatively uncommon but may account for up to 20 percent of cases of sudden death among young individuals, according to background data in the study.
"When not properly diagnosed, ARVC/D can result in sudden cardiac death or unnecessary implantation of an ICD," Marcus said.
The most frequent reason for clinical suspicion of ARVC/D was a history of ventricular arrhythmias (70 percent). One subject had cardiac arrest as the first symptom.
"Of particular interest is that 34 percent of the subjects participated in competitive or professional sports prior to diagnosis. An additional 36 percent of patients were active in recreational sports," the authors wrote.
Researchers evaluated the diagnostic performance of the following core laboratory tests performed in this study: ECG, signal average ECG (SAECG), Holter, echocardiogram, RV angiogram, MRI and RV biopsy. The three tests that separately showed a better diagnostic performance were echo, RV angiogram and ECG.
When all seven tests were evaluated as a group, the biggest decline in diagnostic performance resulted from the removal of echo. Removing RV angiogram and SAECG one at a time also caused a decline in testing performance. On the other hand, removing MRI, ECG and RV biopsy, one at a time, caused less decline in the predictive model.
The best six-variable model that performed as well as the full seven-variable model consisted of all tests except the MRI, researchers reported. Researchers noted a high prevalence for MRI false-positives.
When a five-variable model was considered, the best performance was achieved when echo, RV angiogram, ECG, SAECG and Holter were used and MRI and RV biopsy were removed.
When four- and three-variable models were used, the diagnostic performance of testing was significantly compromised.
Researchers concluded that "evaluating RV echocardiogram, RV angiogram, and SAECG is optimal for all successful models. Routinely used ECG and Holter tests complement these tests, providing best diagnostic performance."
There also was a considerable difference in the initial interpretation performed by the referring physicians and the final classification of the presence of ARVC/D after diagnostic tests were evaluated by the core laboratories.
They concluded that their results substantiate the need for multiple diagnostic tests as well as updated, more well-defined criteria for diagnosing the disease.
A second task force has been gathered to modify the criteria for the diagnosis of ARVC/D.