BOSTON – About half of patients who present with a new onset of frequent premature ventricular contractions without obvious underlying heart disease had an underlying myocardial inflammation that was often responsive to immunosuppressive treatment, according to a single-center series of 107 patients.
“Early diagnosis and appropriate treatment with immunosuppressive therapy can significantly affect the clinical course,” although large-scale, multicenter, randomized trials must confirm this as an effective management approach, Dhanunjaya Lakkireddy, MD, said at the annual scientific sessions of the Heart Rhythm Society. He stressed that the anecdotal efficacy seen in this series with immunosuppressive therapy and selected use of ablation treatment for the premature ventricular contractions (PVCs) applies only to patients with new-onset PVCs that occur at a rate of at least 5,000 during 24 hours who also have myocardial inflammation identified by a PET scan showing increased fluorodeoxyglucose (FDG) uptake.
The apparent impact of immunosuppressive treatment was “profound,” Dr. Lakkireddy said. The treatment usually involved prednisone and, in many patients, a second immunosuppressant agent such as azathioprine, cyclophosphamide, or methotrexate. The results suggest “a unique opportunity to intervene early with immunosuppression to change the natural course of the disease. PVCs may be the earliest sign of a disease process” featuring myocardial inflammation.
The data came from the Myocarditis and Ventricular Arrhythmia (MAVERIC) registry that Dr. Lakkireddy and his associates started because “we began seeing patients referred for ablations without underlying heart disease who had suddenly presented with a lot of PVCs,” he recalled, an observation that led them to systematically study these patients in an “arduous” process that involved several tests. One hundred seven patients met the registry’s inclusion criteria for new onset of frequent PVCs without apparent underlying heart disease, and roughly half of these patients showed clear evidence of myocardial inflammation by FDG and PET imaging. “If the PET is negative, I don’t worry about myocarditis, “ Dr. Lakkireddy said.
The 55 patients with apparent myocarditis on PET imaging, out of the 107 patients examined generally, had lower left ventricular (LV) ejection fractions averaging 46%, compared with 51% among the patients without myocarditis The patients with myocarditis further subdivided into 27 with preserved LV function, with an average ejection fraction of 60%, and 28 with a reduced LV function, with an average ejection fraction of 40%. The researchers saw an optimal response to immunosuppressive therapy in 18 of the 23 patients (78%) with preserved ejection fractions who received this treatment and in 13 of the 24 patients (54%) with diminished LV ejection fractions who got immunosuppressive therapy.
Twenty-eight of the 55 patients with myocarditis on PET imaging underwent a right-sided biopsy during their work-up, and 13 of these 28 biopsies (46%) showed a lymphocytic infiltrate of a type often seen in patients with postviral myocarditis. Seven of the 28 biopsied patients (25%) had completely normal-appearing cardiac tissue.
Dr. Lakkireddy has been a consultant to or has received research support from Biosense Webster, Boehinger Ingelheim, Bristol-Myers Squibb, Estech, Janssen, Pfizer, SentreHeart, and St. Jude.
SOURCE: Lakkireddy D et al. Heart Rhythm 2018, Abstract B-LBCT02-02.