Survival Benefit from Primary Prevention Implantable Cardioverter Defibrillators

MedicalResearch.com Interview with:

Daniel J. Friedman, MD Duke University Hospital Duke Clinical Research Institute Durham, NC

Dr. Friedman

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.

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Effects of ICD Shock and Anti-Tachycardia Pacing on Anxiety and Quality of Life

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.

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Ventricular Arrhythmias Are Common in Patients With Advanced Cancers and ICDs

MedicalResearch.com Interview with:

Andrés Enriquez, MD Heart Rhythm Service Queen’s University and Kingston General Hospital Kingston, Ontario, Canada

Dr. Andres Enriquez

Andrés Enriquez, MD
Heart Rhythm Service
Queen’s University and Kingston General Hospital
Kingston, Ontario, Canada

MedicalResearch.com: What is the background for this study? What are the main findings?

Dr. Enriquez: An increasingly frequent scenario for professionals who work with cardiac implantable devices is being called from the Oncology or Radiotherapy services to assess patients who have received shocks from their implantable cardioverter-defibrillators (ICDs). Interestingly, most of these patients had received their devices for primary prevention and have no prior history of ventricular arrhythmias.

MedicalResearch.com: What is the background for this study? What are the main findings?

Dr. Enriquez: In the present study, the authors analyzed a retrospective cohort of 1598 patients with ICDs followed at the Device Clinics of Kingston, Ontario. Of these, 102 patients (6.2%) received a pathological diagnosis of cancer. After the diagnosis of malignancy, 32% of patients experienced ventricular arrhythmias (VT/VF) over a follow-up period of ~2 years. The frequency of arrhythmic events increased by a factor of 10 after the diagnosis of cancer (1.19 ± 0.32 versus 0.12 ± 0.21 episodes per month, respectively; p 0.03) and was markedly higher in patients with stage IV cancer than in those with earlier stages (p 0.03). In this group, the incidence of VT/VF was 41.2%, with an average of 7.2 ± 18.5 events per patient, all of whom received ICD shocks.

MedicalResearch.com: What should readers take away from your report?

Dr. Enriquez: The main conclusion of this study is that ventricular arrhythmias are frequent in patients with cancer and ICDs and the incidence is higher in those with advanced metastatic disease.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Dr. Enriquez: The association between cardiac disease and cancer is not casual. Both conditions are prevalent (first and second cause of death in developed countries, respectively) and share common risk factors, including tobacco abuse and an unhealthy diet. However, the pathophysiological mechanisms underlying the increased incidence of ventricular arrhythmias in cancer are not clear and deserve further investigation. Possible factors include systemic proinflammatory state, tumoral involvement of the heart, electrolytic imbalances and cardiotoxic effects of antineoplastic drugs or radiation therapy.

MedicalResearch.com: Is there anything else you would like to add?

Dr. Enriquez: A side message of this study is that ICD deactivation was only performed in one third of patients with stage IV cancer. ICD shocks are painful, provoke anxiety and may prolong the process of dying. On the other side, sudden arrhythmic death is the kind of death most people hope for: painless, quick and peaceful. ICD handling is an important aspect of care in patients nearing end of life and physicians should discuss with patients and families the option of ICD deactivation. In accordance with a 2010 consensus statement issued by the Heart Rhythm Society, ICD deactivation is neither physician-assisted suicide nor euthanasia and is ethically acceptable if concordant with patient’s goals of care.

MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.

Citation:

Enriquez A, Biagi J, Redfearn D, et al. Increased Incidence of Ventricular Arrhythmias in Patients With Advanced Cancer and Implantable Cardioverter-Defibrillators.JACCCEP. 2016;():. doi:10.1016/j.jacep.2016.03.001.

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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Electromagnetic Interference Between Smart Phones and Cardiac Devices Rare But Possible

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. Continue reading