Author Interviews, Circadian Rhythm, Heart Disease, JACC / 11.08.2019

MedicalResearch.com Interview with: Dr. Alan Cheng, MD MBA Vice President at Medtronic Clinical Research and Therapy Development, Cardiac Rhythm Management Medtronic, Minnesota 55112  MedicalResearch.com: What is the background for this study? What are the main findings? Response: Ventricular arrhythmias can be life threatening among patients with certain types of heart disease. While implantable cardioverter defibrillators (ICDs) have become the primary means in managing these events, we still don’t fully understand when ventricular arrhythmias occur and whether they are just random events that occur at any time of the day. We pooled patient-level data from 6 prospective studies of ICD recipients and leveraged the continuous monitoring features of the ICD to understand when ventricular arrhythmias occur. Across almost 4000 patients with almost 2 years average follow up from the time of implant, we saw that ventricular arrhythmias aren’t randomly distributed throughout the day. In fact, there is a predilection for these events to occur during normal waking hours as compared to the times of the day when most patients are asleep. Additionally, we found that across the year, the spring season had higher rates of arrhythmia occurrence when compared to summer. We didn’t observe any differences in arrhythmia occurrence by the days of the week or months of the year. This analysis is not the first to explore this question but it is the largest to date.  (more…)
Author Interviews, Duke, Heart Disease / 15.06.2017

MedicalResearch.com Interview with: Daniel J. Friedman, MD Duke University Hospital Duke Clinical Research Institute Durham, NC MedicalResearch.com: What is the background for this study? What are the main findings? Response: Although primary prevention ICDs have saved countless lives among patients with heart failure and a reduced ejection fraction, the use of primary prevention ICDs in patients with more advanced heart failure [defined by New York Heart Association Class (NYHA)] is controversial. Specifically, there are conflicting data from the pivotal primary prevention ICD trials regarding whether primary prevention ICDs reduce all-cause mortality among patients with a severely reduced ejection fraction (≤35%) and NYHA III heart failure. We performed a patient level meta-analysis using data from 4 pivotal primary prevention ICD trials (MADIT-I, MADIT-II, SCD-HeFT, and DEFINITE) to assess whether primary prevention ICD efficacy varied by NYHA class (II vs. III). Overall, the ICD reduced all-cause mortality among the overall population of patients (NYHA II and III). We subsequently assessed ICD efficacy after stratification by NYHA class. Among NYHA II patients, the ICD significantly reduced all-cause mortality by reducing sudden cardiac death. Although NYHA III patients randomized to an ICD experienced a significantly lower rate of sudden cardiac death, this did not translate into a reduction in all-cause mortality, due to competing causes of non-sudden death (which an ICD cannot treat). Based on relatively wide confidence intervals associated with the estimate for ICD effect in NYHA III patients, there appears to be substantial heterogeneity in outcomes among these patients. This suggests that many NYHA III patients can benefit from a primary prevention ICD, but further study is necessary to determine which NYHA III patients are poised to benefit. (more…)
AHA Journals, Author Interviews, Heart Disease, Mental Health Research / 04.04.2017

MedicalResearch.com Interview with: Alessandro Paoletti Perini, MD, PhD and Valentina Kutyifa MD, PhD University of Rochester Medical Center Heart Research Follow-Up Program Rochester, New York, 14642 MedicalResearch.com: What is the background for this study? What are the main findings? Response: The present study is a pre-specified sub-study of the Multicenter Automatic Defibrillator Implantation Trial – Reduce Inappropriate Therapy (MADIT-RIT), which was published on the New England Journal of Medicine in 2012. The main trial showed that innovative ICD programming was associated with reduction in inappropriate ICD therapy and mortality. In the present investigation we focused on the detrimental effects that ICD firings, either appropriate or inappropriate, may have on patients’ psychological well-being. We observed that multiple appropriate and inappropriate shocks are associated with increased levels of ICD-related anxiety, a specific kind of psychological disorder which affects patients implanted with an ICD. Multiple appropriate ATP were also proved associated with higher anxiety, although not as much as shocks. On the other hand, we did not find a significant association with anxiety for multiple inappropriate ATP. (more…)
Author Interviews, Heart Disease, Technology / 26.06.2015

Dr. Carsten Lennerz Deutsches Herzzentrum München MedicalResearch.com Interview with: Dr. Carsten Lennerz Deutsches Herzzentrum München Medical Research: What is the background for this study? What are the main findings? Response: The number of cardiovascular implantable electronic devices (CIEDs) is increasing. Worldwide more than 4 million people rely on an implanted pacemaker (PM) or implantable cardioverter defibrillator ICD. Sensing intrinsic cardiac electrical activity is the core principle of all CIED devices, however in case of electromagnetic interference (EMI) exogenous electric and magnetic fields can be picked up by the sensing circuit and mistakenly interpreted as a cardiac signal by the CIED. PM can respond to EMI with pacing-inhibition, leading to bradycardia or asystole and resulting in syncope. In ICDs EMI may be detected as a life threatening ventricular arrhythmia with the subsequent delivery of inappropriate shocks. Early studies on EMI, run more than 10 years ago, have identified mobile phones as a source of EMI with pacemakers. Based on these pacemaker studies the CIED manufacturer and the regulatory authorities (e.g. Food and Drug Administration [FDA]) currently recommend a safety distance, i.e. hold the phone to the contra-lateral ear and avoid placing a turned-on phone next to the generator pocket. In the meantime telecommunication and the CIED techniques have dramatically evolved. The classic mobile phone has been replaced by modern smartphones, furthermore the network standards have changed from GSM to UMTS (3G) and LTE (4G). New cardiac devices are now in use including more devices for cardiac resynchronisation therapy (CRT) or for the protection from sudden cardiac death (ICD); some of them are even compatible for MRI diagnostics. With the use of a hemertic titanium shell, new filtering properties of the feed-throughs, sense amplifiers and noise protection algorhythms as well as the predominant use of bipolar leads the CIED may be better shielded against external influences and adverse effects of EMI. In light of the above, the purpose of our study was to evaluate if previous precautions recommended to cardiovascular implantable electronic devices recipients are still up-to-date or if they can be abandoned. By today there are neither studies focusing on EMI between modern smartphones and modern CIEDs nor on newer mobile network standards (UMTS or LTE). In a cross-sectional study we enrolled 308 patients and exposed them to the electromagnetic field of three smartphones (Samsung Galaxy 3, Nokia Lumia, HTC One XL) by placing the handhelds directly over the pulse generator. Installing an own base mobile network station we ensured that each smartphone went through a standardized protocol that included the entire calling process (connecting, ringing, talking), the handovers between all current network standards (GSM, UMTS, LTE where applicable) and operation at maximal transmission power. More than 3.400 tests on electromagnetic interference were performed. One out of 308 patients (0.3%) was repeatedly affected by EMI caused by smartphones. The patient’s MRI compatible CRT-defibrillator malfunctioned with short-term ventricular and atrial oversensing when exposed to Nokia or HTC smartphones operating at GSM and UMTS. (more…)