Letter from the Editor

Five Most Important EP Publications From 2017

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Bradley P. Knight, MD, FACC, FHRS, Editor-in-Chief

Below is a list of the top five EP publications from 2017, admittedly subjective and arbitrary:

  1. 1. Noninvasive Cardiac Radiation for Ablation of Ventricular Tachycardia1: In this study, described in the New York Times on December 13, 2017 as “a ‘game changer’ for patients with irregular heart rhythm,” Drs. Phil Cuculich, Cliff Robinson, and their group from Washington University described five patients with recurrent ventricular tachycardia (VT) refractory to conventional therapy, including catheter ablation when feasible, who were treated with focal radiation therapy to a specific ventricular target. These patients experienced a dramatic reduction in VT episodes and defibrillator shocks after treatment. There are obvious technical challenges and concerns about both acute and long-term collateral damage, but this noninvasive method of ablating arrhythmogenic substrates is now an active field of investigation.
  2. 2. Subcutaneous Implantable Cardioverter-Defibrillator (S-ICD) Post-Approval Study2: The FDA required this study as a condition of approval of the S-ICD to assess the real-world experience with the new device in the United States. A total of 1,637 patients underwent device implantation. Unlike the pivotal trial that led to FDA approval and had strict inclusion criteria, 13% of patients were on hemodialysis. The mean age was 52 ± 15 years.  General anesthesia was used in 64% of the patients, and the 2-incision technique was used in 52%. Defibrillation with the S-ICD was successful in 98.7% of the 1,412 patients who underwent testing at the time of implantation. The 30-day complication rate was 3.8% and predictors of complications were diabetes, younger age, and obesity. This study provides additional evidence that the S-ICD technology is a mainstream option for patients at risk of sustained ventricular arrhythmias and who do not require pacing.
  3. MagnaSafe3: Many centers have demonstrated that the performance of an MRI in patients with pacemakers and defibrillators that are not MRI-conditional is safe when using a 1.5 Tesla machine as well as a strict device screening and programming protocol before, during, and after imaging. In this trial, a total of 1,500 non-thoracic MRIs were performed on patients with a non–MRI-conditional device. No patient whose device was programmed in accordance with a standardized protocol had device or lead failure. An additional study, also published in 2017 in the New England Journal of Medicine but from the Hopkins group, confirmed the safety of MRI in 1,509 patients with cardiac devices.4 Others studies have found that thoracic MRI, during which the device is in the isocenter, is also safe in these patients.5 Evidence such as this may lead to Medicare reimbursement for MRIs in these patients in the future. 
  4. 4. The CAMERA-MRI Study6: There is growing evidence that restoration of sinus rhythm is beneficial in patients with atrial fibrillation (AF) and heart failure (HF) when treated with catheter ablation. This study randomized patients with persistent AF and a nonischemic dilated cardiomyopathy to catheter ablation versus continued rate control with medical therapy. Patients had continuous persistent AF for an average of nearly two years, with 3/4 of patients having long-standing persistent AF over one year, and almost all patients had previously failed amiodarone and multiple cardioversions. The improvement in ejection fraction was 18% in the ablation group compared to 4% in the control group. Amazingly, 58% of patients in the ablation group had normalization of their ejection fraction compared to only 9% in the control group. Using data from implantable loop recorders, the average burden of AF was only 1.6% at six months after a short blanking period of 4 weeks. Patients with no scar by MRI had a 73% chance of normalizing their ejection fraction at six months.
  5. 5. Declining Risk of Sudden Death in Heart Failure7: This study looked at data from 40,195 patients with HF and reduced ejection fraction from twelve clinical trials between 1995 and 2014, and concluded that sudden cardiac death rates have declined substantially over time. This analysis suggests that medical therapy for HF is increasingly effective at preventing sudden death in HF patients, and implies that the potential benefits of ICD therapy in patients with HF may be decreasing over time.

References

  1. Cuculich PS, Schill MR, Kashani R, et al. Noninvasive Cardiac Radiation for Ablation of Ventricular Tachycardia. N Engl J Med. 2017;377:2325-2336. doi: 10.1056/NEJMoa1613773.
  2. Gold MR, Aasbo J, El-Chami MF, et al. Subcutaneous implantable cardioverter-defibrillator Post-Approval Study: Clinical characteristics and perioperative results. Heart Rhythm. 2017;14(10):1456-1463. doi: 10.1016/j.hrthm.2017.05.016. 
  3. Russo RJ, Costa HS, Silva PD, et al. Assessing the risks associated with MRI in patients with a pacemaker or defibrillator. N Engl J Med. 2017;376:755-764. doi: 10.1056/NEJMoa1603265.
  4. Nazarian S, Hansford R, Rahsepar AA, et al. Safety of Magnetic Resonance Imaging in Patients with Cardiac Devices. N Engl J Med. 2017;377(26):2555-2564. doi: 10.1056/NEJMoa1604267.
  5. Dandamudi S, Collins JD, Carr JC, et al. The Safety of Cardiac and Thoracic MR Imaging in Patients with Cardiac Implantable Electronic Devices. Acad Radiol. 2016;23(12):1498-1505. doi: 10.1016/j.acra.2016.08.016.
  6. Prabhu S, Taylor AJ, Costello BT, et al. Catheter Ablation Versus Medical Rate control in Atrial Fibrillation and Systolic Dysfunction: The CAMERA-MRI Study. J Am Coll Cardiol. 2017;70(16):1949-1961. doi: 10.1016/j.jacc.2017.08.041.
  7. Shen L, Jhund PS, Petrie MC, et al. Declining Risk of Sudden Death in Heart Failure. N Engl J Med. 2017;377(1):41-51. doi: 10.1056/NEJMoa1609758.
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