Detection of enterovirus RNA in myocardial biopsies from patients with myocarditis and cardiomyopathy using gene amplification by polymerase chain reaction.

TLDR

Recent molecular studies suggest viral myocarditis often underlies congestive cardiomyopathy, but prior methods were only moderately sensitive and specific, whereas PCR gene amplification offers a sensitive, specific technique for detecting viral genomes in small tissue samples. The study employed high‑stringency PCR gene amplification to screen 48 myocardial biopsies from patients with suspected myocarditis or dilated cardiomyopathy, and also tested ventricular samples from hypertrophic cardiomyopathy patients, normal hearts, and uninfected monkey kidney cells, all yielding negative results. PCR detected enteroviral RNA in five patients—two with myocarditis and three with cardiomyopathy—while four previously diagnosed myocarditis patients were now PCR‑negative, and all other patients remained negative, supporting a link between viral infection and dilated cardiomyopathy and establishing PCR as a new diagnostic approach.

Abstract

Recent molecular studies have suggested that viral myocarditis frequently underlies human congestive cardiomyopathy; however, only moderately sensitive and specific techniques were used. Polymerase chain reaction (PCR) gene amplification is a sensitive, specific technique ideally suited for the diagnosis of viral disease in small tissue samples where low copy numbers of the viral genome may be present. Using PCR and high stringency condition, we screened biopsies taken from 48 patients with clinically suspected myocarditis or dilated cardiomyopathy. Five patients demonstrated positive enteroviral signals by PCR; two of them had myocarditis by pathology, whereas the other three had changes consistent with cardiomyopathy. Four other patients had myocarditis diagnosed by pathology from 3 months to 1 year earlier but were now negative by both PCR and pathology. Both pathology and PCR were negative for active myocarditis in all other patients. Ventricular samples taken from left ventricular myectomy in four additional patients with hypertrophic cardiomyopathy, normal human ventricle samples, and uninfected monkey kidney cells were also negative by PCR. This study supports a link between viral infection and dilated cardiomyopathy in some patients. PCR gene amplification provides a new diagnostic approach to patients with suspected myocarditis.