Clinical outcome in patients with implantable cardioverter-defibrillator and cancer: a nationwide study.

Aims: Patients with cancer are insufficiently represented in randomized clinical trials investigating efficacy of implantable cardioverter-defibrillators (ICDs). We aimed to describe outcomes in patients with a pre-existing diagnosis of cancer at time of ICD implantation.

Methods And Results: We utilized Danish nationwide registries to identify primary and secondary prevention ICD implantations from 2007 to 2012.

Predicting electrical storms by remote monitoring of implantable cardioverter-defibrillator patients using machine learning.

Aims: Electrical storm (ES) is a serious arrhythmic syndrome that is characterized by recurrent episodes of ventricular arrhythmias. Electrical storm is associated with increased mortality and morbidity despite the use of implantable cardioverter-defibrillators (ICDs). Predicting ES could be essential; however, models for predicting this event have never been developed.

Shortening of paced QRS duration after electrocardiographic optimization of left ventricular pacing vector in patients treated with Cardiac Resynchronization Therapy.

Background: Choice of left ventricular pacing vector (LVPV) affects the QRS-duration (QRSd) in patients with Cardiac Resynchronization Therapy (CRT). It is not known whether testing all LVPVs reduces QRSd compared to device-based “standard-programming”.

Methods: In patients implanted with CRT several ECGs were recorded for each usable LVPV (no phrenic nerve stimulation and threshold <3.

Precision of automated QRS duration measurement in patients treated with cardiac resynchronization therapy.

Purpose: Shortening of the QRS duration (QRSd) is often used to guide device optimization and reprogramming in patients with cardiac resynchronization therapy (CRT). Detecting the small changes expected during reprogramming requires that the QRSd can be measured with high precision, but this has never been studied in patients with CRT. In this study, we wanted to assess the precision of automated QRSd measurement in patients treated with CRT using two commonly available electrocardiographs.

Association between right ventricular lead position and clinical outcomes in patients with cardiac resynchronization therapy.

Aims: To evaluate the association between an apical vs. non-apical right ventricular lead position (RV-LP) and clinical outcome in a large nationwide cohort of patients treated with cardiac resynchronization therapy (CRT).

Methods And Results: We included consecutive Danish patients receiving a CRT device from 2008 to 2012, identified from the Danish Pacemaker and ICD Register.

The use of guideline recommended beta-blocker therapy in primary prevention implantable cardioverter defibrillator patients: insight from Danish nationwide registers.

Aims: We aimed to examine the use of guideline recommended beta-blocker therapy prior to and after primary prevention implantable cardioverter defibrillator (ICD) implantation in a 'real-life' setting.

Methods And Results: From the Danish Pacemaker and ICD Registry we identified all 1st-time primary prevention ICD and cardiac resynchronization therapy defibrillator (CRT-D) implantations in Denmark from 2007-12 (n = 2935). Use of beta-blocker, type and dose was acquired through the Danish Prescription Registry.

The impact of co-morbidity burden on appropriate implantable cardioverter defibrillator therapy and all-cause mortality: insight from Danish nationwide clinical registers.

Aims: In a nationwide cohort of primary (PP-ICD) and secondary prevention (SP-ICD) implantable cardioverter defibrillator (ICD) patients, we aimed to investigate the association between co-morbidity burden and risk of appropriate ICD therapy and mortality.

Methods And Results: We identified all patients >18 years, implanted with first-time PP-ICD (n = 1873) or SP-ICD (n = 2461) in Denmark from 2007 to 2012. Co-morbidity was identified in administrative registers of hospitalization and drug prescription from pharmacies.

Safety of magnetic resonance scanning without monitoring of patients with pacemakers.

Aims: The objective of this study was to investigate whether it is safe to perform 1.5-Tesla magnetic resonance imaging (MRI) scans in pacemaker (PM) patients without pulse oximetry or electrocardiogram monitoring and with no special specific absorption rate (SAR) or time limits, provided that the PMs are interrogated and programmed to asynchronous mode prior to the scan.

Methods And Results: This study reports the outcome of 207 MRI scans on PM patients at Rigshospitalet, Copenhagen University Hospital from June 2010 to September 2013.

Validation of defibrillator lead performance registry data: insight from the Danish Pacemaker and ICD Register.

Aims: The validity of registry data on defibrillator lead performance is described only sparsely, despite its clinical importance. This study investigated the validity of defibrillator lead performance registry data in a nationwide and population-based registry.

Methods And Results: We identified all reported surgical interventions due to defibrillator lead events in the Danish Pacemaker and ICD Register (DPIR) from 2000 to 2013.

An anterior left ventricular lead position is associated with increased mortality and non-response in cardiac resynchronization therapy.

Background: Non-response to cardiac resynchronization therapy (CRT) might be due to insufficient resynchronization as a result of a sub-optimal left ventricular lead positon (LV-LP).

Objective: To evaluate the impact of different LV-LPs on mortality and symptomatic improvement in a large cohort of patients treated with CRT.

Methods: We performed a nationwide cohort study on consecutive patients receiving a CRT device from 1997 to 2012 registered in the Danish pacemaker and ICD register.

Is modification of the VVI backup mode in implantable cardioverter-defibrillators from St Jude medical required due to increased risk of inappropriate shocks?

Inappropriate implantable cardioverter-defibrillator (ICD) shock therapy is painful, stressful, and typically occurs unexpected in conscious patients and may be related to a less favourable prognosis. In our institution, we have observed four cases of multiple inappropriate ICD shocks during reset to VVI backup mode. All four patients were implanted with a St Jude Medical ICD since 2010.

Single-coil and dual-coil defibrillator leads and association with clinical outcomes in a complete Danish nationwide ICD cohort.

Background: The best choice of defibrillator lead in patients with routine implantable cardioverter-defibrillator (ICD) is not settled. Traditionally, most physicians prefer dual-coil leads but the use of single-coil leads is increasing.

Objective: The purpose of this study was to compare clinical outcomes in patients with single- and dual-coil leads.

The patient perspective on the Riata defibrillator lead advisory: a Danish nationwide study.

Background: The St Jude Medical Riata lead advisory was issued owing to insulation failures. The impact of this advisory on patients' well-being is unknown.

Objectives: The objectives of this study were to describe the acute impact of the Riata advisory on patients' well-being and psychological functioning and to examine changes over time.

Prospective nationwide fluoroscopic and electrical longitudinal follow-up of recalled Riata defibrillator leads in Denmark.

Background: Recalled St. Jude Medical Riata defibrillator leads are prone to insulation failures with externalized conductors (ECs). Longitudinal studies are needed to guide lead management.

Patient satisfaction and suggestions for improvement of remote ICD monitoring.

Purpose: The study aim was to evaluate patient acceptance and content with remote follow-up (FU) of their implantable cardioverter defibrillator (ICD) and to estimate patients' wish for changes in remote follow-up routines.

Methods: Four hundred seventy-four ICD patients at the device follow-up clinic at Rigshospitalet using CareLink® (Medtronic) remote follow-up, who had made ≥2 transmissions, received a questionnaire.

Results: Three hundred eighty-five patients (81.

Indication of the radiofrequency induced lesion size by pre-ablation measurements.

Background: During radiofrequency ablation of arrhythmias tissue heating and hence lesion size depend on electrode-tissue contact and cooling of the electrode tip caused by cavitary blood flow. These factors are unique and unknown for each catheter placement in the beating heart. A tool for assessing these factors prior to ablation may indicate the lesion size which will be obtained for any given catheter position.

Mechanisms for enlarging lesion size during irrigated tip radiofrequency ablation: is there a virtual electrode effect?

Introduction: Irrigated tip radiofrequency ablation of cardiac arrhythmias was developed to increase the size of the radiofrequency-induced lesion, since cooling of the electrode tip allows use of higher power settings. The purpose of this study was to determine if the increased lesion size during irrigated tip ablation is caused by the cooling effect solely or if increased electrical conductivity around the tip also contributes by increasing the "current-delivering size" of the tip: the so-called "virtual electrode effect."

Methods And Results: In vitro strips of left ventricular porcine myocardium and in vivo canine left ventricles were ablated.

Can lesion size during radiofrequency ablation be predicted by the temperature rise to a low power test pulse in vitro?

During radiofrequency ablation sufficient power must be delivered to achieve a proper lesion, while tissue temperatures are kept below 100 degrees C. Tissue temperature and hence lesion size are determined by electrode to tissue contact and convective cooling, which vary with any obtained electrode position in the beating heart. A tool for evaluation of the combined effect of these parameters prior to ablation to predict the resulting lesion size for any actually obtained electrode position would be valuable.