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Myocarditis shows causal role in frequent PVCs

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Findings raise shock and alarm

I was quite taken by this study, which produced results that raise shock and alarm. I believe that the clinical condition that this study highlights is a real biological phenomenon that affects patients who were not on my radar screen.

Dr. David J. Callans, professor of medicine and associate director of electrophysiology at the University of Pennsylvania in Philadelphia. Mitchel L. Zoler/MDedge News

Dr. David J. Callans

The condition that Dr. Lakkireddy described is a more subtle myocarditis than what we usually see, and that is part of what makes it alarming. The findings make me wonder how many patients like these do I have in my practice, and how many of them have I been missing? I think the answer is probably some. The results make it clear that some patients who develop myocarditis also have frequent premature ventricular contractions, and that we should be more worried about these patients than we have been in the past.

From now on, I will certainly be more alert for and concerned about patients whom I see with an abrupt onset of frequent premature ventricular contractions, especially those who also have a reduced left ventricular ejection fraction. However the potential need to use serial PET examinations to identify and then follow these patients also raises concern about the cumulative radiation exposure patients could receive from serial PET studies.

David J. Callans, MD , is professor of medicine and associate director of electrophysiology at the University of Pennsylvania in Philadelphia. He has been a consultant to Abbott, Biosense Webster, Biotronik, Boston Scientific, Medtronic, and St. Jude. He made these comments as designated discussant for the report.



– 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.

Dr. Dhanunjaya Lakkireddy, medical director, Kansas City Heart Rhythm Institute, Overland Park, Kan. Mitchel L. Zoler/MDedge News

Dr. Dhanunjaya Lakkireddy

Of the 46 patients who underwent this treatment, 31 (67%) had an optimal response – resolution of FDG uptake by the myocardium and at least an 80% cut in PVC count – and another 7 patients (15%) responded but less robustly during an average follow-up of 6 months. In contrast, six of the nine untreated patients either progressed or had no change in their disease severity, while three untreated patients showed suboptimal improvement, reported Dr. Lakkireddy, medical director of the Kansas City Heart Rhythm Institute in Overland Park, Kan.

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.

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