MAVERIC, CABANA and more………
Dhanunjaya Lakkireddy, Andrea Natale
Welcome to the May issue of the Journal of Atrial Fibrillation. Somehow Spring totally skipped North America this year. We jumped straight from Winter to a Toasty Summer already with record 3-digit temperatures by the end of May. Untimely tropical storms in the Southeast and volcanic eruptions in the Hawaii island all of it can point to some sinister climatic changes that we may want to think twice about. Or may be its all fake news!!
Heart Rhythm Society (HRS) successfully completed the 39th annual sessions in Boston with another great turnout from all around the world. We want to congratulate George Van Hare MD, the immediate past president of HRS for his contributions to the society and his leadership. Hearty welcome to Thomas Deering MD on his new assignment to be the current President of HRS. Tom in his acceptance speech has laid out his vision for the society’s grass roots level engagement and global outreach.
There were several thought-provoking studies and many more exciting ideas presented at the HRS, that will continue to advance the field of Electrophysiology. Of the several late breaking clinical trials presented some are worth talking about. There was a late breaking clinical trial that summed the cumulative data on device related thrombus from the Watchman experience. This opened several important questions about the need for extended surveillance in the post implant phase and whether we should understand the factors that drive this. Or newer devices could potentially address this issue by making some structural changes. May be epicardial left atrial appendage excluders are better choices! The MAVERIC registry from our group looked at the potential etiopathogenesis of high burden- symptomatic premature ventricular contractions. It is sobering to know that more than 50% of these patients may actually have underlying myocarditis as an inciting cause. Systematic use of Fluorodeoxy Glucose mediated Positron Emission Tomography (FDG-PET) and Magnetic Resonance Imaging with delayed hyperenhancement (MRI-DHE) may help identify these patients who may represent the early phase of the initiation of non-ischemic cardiomyopathic process. Perhaps, aggressive upstream therapy of myocarditis may have some several important implications that are worth taking into consideration. Steroids were helpful only marginally and use of real immunosuppressants like methotrexate, mycophenolate etc, was successfully in treating the myocarditis associated with excellent clinical response. This we believe is the first step towards our understanding of the non-ischemic cardiomyopathies.
Then the most anticipated study of the last decade – CABANA! Doug Packer and co-investigators presented the results of a randomized controlled trial that looked at the difference between catheter ablation and medical therapy with antiarrhythmic drugs. A total of 2204 patients were enrolled. 9% of patients randomized to the ablation arm never got it and 28% of patients randomized to the drug arm moved on to get an ablation before the completion of the 5 year follow up. Even though the intention to treat analysis showed no significant difference in the primary outcomes, we still believe that CABANA still revealed several important positive attributes of therapeutic ablation. Patient who had CA have 47% higher chance staying in sinus rhythm and those who actually received CA have improved mortality (40%). The primary end points of death, strokes, bleeding, and cardiac arrests of this study was dramatically lowered with ablation. In fact, those patients who actually got an ablation in this study experienced a 33% lower risk of death, strokes, bleeding, or cardiac arrest. While it is disappointing for puritan trialists it is win for patients who continue to show significant improvement in their quality of life. This is a perfect example of how intention-to-treat analysis may not be the end all approach to analyze and understand the impact of therapeutic strategies. While the debate continues, for those who oppose catheter ablation what other real options do you have – Angiotensin receptor blockers, statins and magnesium supplements? It was interesting that in a recent debate a famous CA contrarian agreed that he will consider ablation if he were to develop symptomatic AF. While meaningful scientific discourse is important, pragmatic approaches to cure diseases is our responsibilities as the takers of the Hippocratic Oath. The full manuscript on this study will hopefully come out soon and address the many unanswered questions.
Dhanunjaya (DJ)Lakkireddy MD, FACC, FHRS Associate Editor JAFIB
Andrea Natale MD, FACC, FHRS, FESC Editor-in-Chief JAFIB