ISE/ISHNE expert consensus statement on the ECG diagnosis of left ventricular hypertrophy: The change of the paradigm.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria. The classical paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces, reflected in the augmented QRS amplitude. However, the low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm. The theoretical background for voltage measured at the body surface is defined by the solid angle theorem, which relates the measured voltage to spatial and non-spatial determinants. The spatial determinants are represented by the extent of the activation front and the distance of the recording electrodes. The non-spatial determinants comprise electrical characteristics of the myocardium, which are comparatively neglected in the interpretation of the QRS patterns. Various clinical conditions are associated with LVH. These conditions produce considerable diversity of electrical properties alterations thereby modifying the resultant QRS patterns. The spectrum of QRS patterns observed in LVH patients is quite broad, including also left axis deviation, left anterior fascicular block, incomplete and complete left bundle branch blocks, Q waves, and fragmented QRS. Importantly, the QRS complex can be within normal limits. The new paradigm stresses the electrophysiological background in interpreting QRS changes, i.e., the effect of the non-spatial determinants. This postulates that the role of ECG is not to estimate LV size in LVH, but to understand and decode the underlying electrical processes, which are crucial in relation to cardiovascular risk assessment.

Myocardial scarring and recurrence of ventricular arrhythmia in patients surviving an out-of-hospital cardiac arrest.

INTRODUCTION: Prediction of recurrent ventricular arrhythmia (VA) in survivors of an out-of-hospital cardiac arrest (OHCA) is important, but currently difficult. Risk of recurrence may be related to presence of myocardial scarring assessed with late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Our study aims to characterize myocardial scarring as defined by LGE-CMR in survivors of a VA-OHCA and investigate its potential role in the risk of new VA events. METHODS: Between 2015 and 2022, a total of 230 VA-OHCA patients without ST-segment elevation myocardial infarction had CMR before implantable cardioverter-defibrillator implantation for secondary prevention at Copenhagen University Hospital, Rigshospitalet, and Hospital Clínic, University of Barcelona, of which n = 170 patients had a conventional (no LGE protocol) CMR and n = 60 patients had LGE-CMR (including LGE protocol). Scar tissue including core, border zone (BZ) and BZ channels were automatically detected by specialized investigational software in patients with LGE-CMR. The primary endpoint was recurrent VA. RESULTS: After exclusion, n = 52 VA-OHCA patients with LGE-CMR and a mean left ventricular ejection fraction of 49 ± 16% were included, of which 18 (32%) patients reached the primary endpoint of VA. Patients with recurrent VA in exhibited greater scar mass, core mass, BZ mass, and presence of BZ channels compared with patients without recurrent VA. The presence of BZ channels identified patients with recurrent VA with 67% sensitivity and 85% specificity (area under the ROC curve (AUC) 0.76; 95% CI: 0.63-0.89; p < .001) and was the strongest predictor of the primary endpoint. CONCLUSIONS: The presence of BZ channels was the strongest predictor of recurrent VA in patients with an out of-hospital cardiac arrest and LGE-CMR.

Incidence of thyroid dysfunction following initiation of amiodarone treatment in patients with and without heart failure: a nationwide cohort study.

AIMS: Thyroid dysfunction is considered the most frequent complication to amiodarone treatment, but data on its occurrence outside clinical trials are sparse. The present study aimed to examine the incidence of thyroid dysfunction following initiation of amiodarone treatment in a nationwide cohort of patients with and without heart failure (HF). METHODS AND RESULTS: In Danish registries, we identified all patients with first-time amiodarone treatment during the period 2000-18, without prior thyroid disease or medication. The primary outcome was a composite of thyroid diagnoses and initiation of thyroid drugs. Outcomes were assessed at 1-year follow-up, and for patients free of events in the first year, in a landmark analysis for the subsequent 5 years. We included 43 724 patients with first-time amiodarone treatment, of whom 16 939 (38%) had HF. At 1-year follow-up, the cumulative incidence and adjusted hazard ratio (HR) of the primary outcome were 5.3% and 1.37 (95% confidence interval 1.25-1.50) in patients with a history of HF and 4.2% in those without HF (reference). In the 1-year landmark analysis, the subsequent 5-year cumulative incidences and adjusted HRs of the primary outcome were 5.3% (reference) in patients with 1-year accumulated dose <27.38 g [corresponding to average daily dose (ADD <75 mg)], 14.0% and HR 2.74 (2.46-3.05) for 27.38-45.63 g (ADD 75-125 mg), 20.0% and HR 4.16 (3.77-4.59) for 45.64-63.88 g (ADD 126-175 mg), and 24.5% and HR 5.30 (4.82-5.90) for >63.88 g (ADD >175 mg). CONCLUSION: Among patients who initiated amiodarone treatment, around 5% had thyroid dysfunction at 1-year follow-up, with a slightly higher incidence in those with HF. A dose-response relationship was observed between the 1-year accumulated amiodarone dose and the subsequent 5-year cumulative incidence of thyroid dysfunction.

Scar border zone mass and presence of border zone channels assessed with cardiac magnetic resonance imaging are associated with ventricular arrhythmia in patients with ST-segment elevation myocardial infarction.

AIMS: Late gadolinium enhancement cardiac magnetic resonance (CMR) permits characterization of left ventricular ischaemic scars. We aimed to evaluate if scar core mass, border zone (BZ) mass, and BZ channels are risk markers for subsequent ventricular arrhythmia (VA) in ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS: A sub-study of the DANish Acute Myocardial Infarction-3 multi-centre trial and Danegaptide phase II proof-of-concept clinical trial in which a total of 843 STEMI patients had a 3-month follow-up CMR. Of these, 21 patients subsequently experienced VA during 100 months of follow-up and were randomly matched 1:5 with 105 controls. A VA event was defined as: ventricular tachycardia, ventricular fibrillation, or sudden cardiac death. Ischaemic scar characteristics were automatically detected by specialized software. We included 126 patients with a median left ventricular ejection fraction of 51.0 ± 11.6% in cases with VA vs. 55.5 ± 8.5% in controls (P = 0.10). Cases had a larger mean BZ mass and more often BZ channels compared to controls [BZ mass: 17.2 ± 10.3 g vs. 10.3 ± 6.0 g; P = 0.0002; BZ channels: 17 (80%) vs. 44 (42%); P = 0.001]. A combination of ≥17.2 g BZ mass and the presence of BZ channels was five times more prevalent in cases vs. controls (P ≤ 0.00001) with an odds ratio of 9.40 (95% confidence interval 3.26-27.13; P ≤ 0.0001) for VA. This identified cases with 52% sensitivity and 90% specificity. CONCLUSION(S): Scar characterization with CMR indicates that a combination of ≥17.2 g BZ mass and the presence of BZ channels had the strongest association with subsequent VA in STEMI patients. CLINICALTRIALS.GOV: Unique identifier: NCT01435408 (DANAMI 3-iPOST and DANAMI 3-DEFER), NCT01960933 (DANAMI 3-PRIMULTI), and NCT01977755 (Danegaptide).

Long-term risk of new-onset arrhythmia in ST-segment elevation myocardial infarction according to revascularization status.

AIMS: Emerging data show that complete revascularization (CR) reduces cardiovascular death and recurrent myocardial infarction in ST-segment elevation myocardial infarction (STEMI). However, the influence of revascularization status on development of arrhythmia in the long-term post-STEMI phase is poorly described. We hypothesized that incomplete revascularization (ICR) compared with CR in STEMI is associated with an increased long-term risk of new-onset arrhythmia. METHODS AND RESULTS: Patients with STEMI treated with primary percutaneous coronary intervention (PPCI) at Copenhagen University Hospital, Rigshospitalet, Denmark, with CR or ICR were identified via the Eastern Danish Heart registry from 2009 to 2016. Using unique Danish administrative registries, the outcomes were assessed. The primary outcome was new-onset arrhythmia defined as a composite of atrial fibrillation/flutter (AF), sinoatrial block, advanced second- or third-degree atrioventricular block, ventricular tachycardia/fibrillation (VT), or cardiac arrest (CA), with presentation >7 days post-PPCI. Secondary outcomes were the components of the primary outcome and all-cause mortality. A total of 5103 patients (median age: 62.0 years; 76% men) were included, of whom 4009 (79%) and 1094 (21%) patients underwent CR and ICR, respectively. Compared with CR, ICR was associated with a higher risk of new-onset arrhythmia [hazard ratio (HR), 1.33; 95% confidence interval (CI), 1.07-1.66; P = 0.01], AF (HR, 1.29; 95% CI, 1.00-1.66; P = 0.05), a combined outcome of VT and CA (HR, 1.77; 95% CI, 1.10-2.84; P = 0.02) and all-cause mortality (HR, 1.27; 95% CI, 1.05-1.53; P = 0.01). All HRs adjusted. CONCLUSION: Among patients with STEMI, ICR was associated with an increased long-term risk of new-onset arrhythmia and all-cause mortality compared with CR.

Severity of Brugada syndrome disease manifestation and risk of new-onset depression or anxiety: a Danish nationwide study.

AIMS: Reduced psychological health is associated with adverse patient outcomes and higher mortality. We aimed to examine if a Brugada syndrome (BrS) diagnosis and symptomatic disease presentation were associated with an increased risk of new-onset depression or anxiety and all-cause mortality. METHODS AND RESULTS: All Danish patients diagnosed with BrS (2006-2018) with no history of psychiatric disease and available for ≥6 months follow-up were identified using nationwide registries and followed for up to 5 years after diagnosis. The development of clinical depression or anxiety was evaluated using the prescription of medication and diagnosis codes. Factors associated with developing new-onset depression or anxiety were determined using a multivariate Cox proportional hazards regression model. Disease manifestation was categorized as symptomatic (aborted cardiac arrest, ventricular tachycardia, or syncope) or asymptomatic/unspecified at diagnosis. A total of 223 patients with BrS and no history of psychiatric disease were identified (72.6% male, median age at diagnosis 46 years, 45.3% symptomatic). Of these, 15.7% (35/223) developed new-onset depression or anxiety after BrS diagnosis (median follow-up 5.0 years). A greater proportion of symptomatic patients developed new-onset depression or anxiety compared with asymptomatic patients [21/101 (20.8%) and 14/122 (11.5%), respectively, P = 0.08]. Symptomatic disease presentation (HR 3.43, 1.46-8.05) and older age (lower vs. upper tertile: HR 4.41, 1.42-13.63) were significantly associated with new-onset depression or anxiety. All-cause mortality in this group of patients treated according to guidelines was low (n = 4, 1.8%); however, 3/4 developed depression or anxiety before death. CONCLUSION: Approximately, one-sixth of patients with BrS developed new-onset depression or anxiety following a diagnosis of BrS. Symptomatic BrS disease manifestation was significantly associated with new-onset depression or anxiety.

Reduced inferior wall longitudinal strain is associated with malignant arrhythmias in non-ischemic heart failure.

BACKGROUND: Reduced systolic myocardial function in the inferior region of the left ventricle has been suggested to be associated with malignant arrhythmias. We tested this hypothesis in patients with non-ischemic heart failure. METHODS: Patients with non-ischemic heart failure (left ventricular ejection fraction [LVEF] < 35%) were evaluated by 2D-speckle-tracking echocardiography. The regional longitudinal strain was calculated for each of the six left ventricular walls. The reduced regional function was defined as strain below the median. The outcome was a composite of sudden cardiac death, admission with sustained ventricular arrhythmia, resuscitated cardiac arrest, and appropriate therapy from a primary prophylactic implantable cardioverter defibrillator. Time-to-first-event analysis was performed using a Cox model. RESULTS: From two centers, 401 patients were included (median age: 63 years, 72% male) with a median LVEF of 25% (interquartile range [IQR] 20;30), and a median inferior wall strain of -9.0% (-12.5; -5.4). During a median follow-up of 4.0 years, 52 outcomes occurred. After multivariate adjustment for clinical and electrocardiographic parameters, inferior wall strain was independently associated with the outcome (HR 2.50 [1.35; 4.62], p = .003). No independent association was found between the composite outcome and reduced strain in any of the other left ventricular walls, Global Longitudinal Strain (HR 1.66 [0.93; 2.98], p = .09), or LVEF (HR 1.33 [0.75; 2.33], p = .33). CONCLUSIONS: Below median strain in the left ventricular inferior region was independently associated with a 2.5-fold increase in the risk of malignant arrhythmias and sudden cardiac death in patients with non-ischemic heart failure.

ISE/ISHNE Expert Consensus Statement on ECG Diagnosis of Left Ventricular Hypertrophy: The Change of the Paradigm. The joint paper of the International Society of Electrocardiology and the International Society for Holter Monitoring and Noninvasive Electrocardiology.

The ECG diagnosis of LVH is predominantly based on the QRS voltage criteria, i.e. the increased QRS complex amplitude in defined leads. The classical ECG diagnostic paradigm postulates that the increased left ventricular mass generates a stronger electrical field, increasing the leftward and posterior QRS forces. These increased forces are reflected in the augmented QRS amplitude in the corresponding leads. However, the clinical observations document increased QRS amplitude only in the minority of patients with LVH. The low sensitivity of voltage criteria has been repeatedly documented. We discuss possible reasons for this shortcoming and proposal of a new paradigm.

Targeted potassium levels to decrease arrhythmia burden in high risk patients with cardiovascular diseases (POTCAST): Study protocol for a randomized controlled trial.

BACKGROUND: Low plasma potassium (p-K) is associated with increased risk of malignant arrhythmia and observational studies indicate protective effects of p-K in the upper reference level. However, randomized clinical studies are needed to document whether actively increasing p-K to high-normal levels is possible and safe and improves cardiovascular outcomes. OBJECTIVE: To investigate if increased p-K reduces the risk of malignant arrhythmia and all-cause death in high-risk patients with a cardiovascular disease treated with an implantable cardioverter defibrillator (ICD) for primary or secondary preventive causes. Secondly, to investigate whether high-normal p-K levels can be safely reached and maintained using already available medications and potassium-rich dietary guidance. METHODS: This is a prospective, randomized, and open-labelled study enrolling patient at high-risk of malignant arrhythmias. According to sample size calculations, 1,000 patients will be randomized 1:1 to either an investigational regiment that aims to increase and maintain p-K at high-normal levels (4.5-5.0 mmol/L) or to usual standard of care and followed for an expected four years. The trial will run until a total of 291 events have occurred providing an α = 0.05 and 1-ß = 0.80. The composite primary endpoint includes ventricular tachycardia >125 bpm lasting >30 seconds, any appropriate ICD-therapy, and all-cause mortality. At present, 739 patients have been randomized. CONCLUSIONS: We present the rationale for the design of the POTCAST trial. The inclusion was initiated 2019 and is expected to be finished 2022. The study will show if easily available treatments to increase p-K may be a new treatment modality to protect against malignant arrythmias.

Comparison of the Anterior Septal Line and Mitral Isthmus Line for Perimitral Atrial Flutter Ablation Using Robotic Magnetic Navigation.

BACKGROUND: Perimitral atrial flutter (PMAFL) is one of the most common macro-reentrant left atrial tachycardias. Mitral isthmus (MI) linear ablation is a common strategy for the treatment of PMAFLs, and anterior septum (AS) linear ablation has emerged as a novel ablation approach. We aimed at assessing the effectiveness of AS linear ablation using robotic magnetic navigation for PMAFL ablation. METHODS: In this retrospective study, a total of 36 consecutive patients presented with AFL as the unique arrhythmia or accompanied with atrial fibrillation (AF) who underwent catheter ablation were enrolled. Patients were classified into two groups according to the different ablation strategies, the MI line group (10 patients) and the AS line group (26 patients). RESULTS: The clinical baseline characteristics of patients in the two groups were nearly identical. There were no significant differences in procedure time (148.7 ± 46.1 vs. 123.2 ± 30.1 min, P=0.058) or radiofrequency ablation time (25.9 ± 11.4 vs. 23.5 ± 12.6 min) between the two groups. Fluoroscopy time was longer in the MI line group (8.0 ± 4.4 vs. 5.1 ± 2.7 min, P=0.024), and the acute success rate was higher in the AS line group versus the MI line group (96.2% vs. 70%, P=0.025). The long-term freedom from arrhythmia survival rate was higher in the AS line group (73%) than in the MI line group (40%) after a mean follow-up time of 37.4 months with a 3-month blanking period (P=0.049). CONCLUSIONS: AS linear ablation is an effective and safe strategy for PMAFL ablation using robotic magnetic navigation.

Driving following defibrillator implantation: a nationwide register-linked survey study.

AIMS: Patients are restricted from driving following implantable cardioverter defibrillator (ICD) implantation or shock. We sought to investigate how many patients are aware of, and adhere to, the driving restrictions, and what proportion experience an ICD shock or other cardiac symptoms while driving. METHODS AND RESULTS: We performed a nationwide survey of all living Danish residents 18 years or older who received a first-time ICD between 2013 and 2016 (n = 3913) and linked their responses with nationwide registers. Of 2741 respondents (47% primary prevention, 83% male, median age 67 years), 2513 (92%) held a valid driver's license at ICD implantation, 175 (7%) of whom had a license for professional driving. Many drivers were unaware of driving restrictions: primary prevention 58%; secondary prevention 36%; post-appropriate shock 28%; professional drivers 55%. Almost all (94%) resumed non-professional driving after ICD implantation, more than one-third during the restricted period; 35% resumed professional driving. During a median follow-up of 2.3 years, 5 (0.2%) reported receiving an ICD shock while driving, one of which resulted in a traffic accident. The estimated risk of harm was 0.0002% per person-year. CONCLUSION: In this nationwide study, many ICD patients were unaware of driving restrictions, and more than one third resumed driving during a driving restriction period. However, the rate of reported ICD shocks while driving was very low.

Risk of arrhythmias after myocardial infarction in patients with left ventricular systolic dysfunction according to mode of revascularization: a Cardiac Arrhythmias and RIsk Stratification after Myocardial infArction (CARISMA) substudy.

AIMS: The Cardiac Arrhythmias and RIsk Stratification after Myocardial infArction (CARISMA) study was an observational trial including 312 patients with acute myocardial infarction (MI) and left ventricular ejection fraction (LVEF) <40%. Primary percutaneous intervention (pPCI) was introduced 2 years after start of the enrolment, dividing the population into two groups: pre- and post-pPCI. This substudy sought to describe the influence of the mode of revascularization on long-term risk of new-onset atrial fibrillation (AF), bradyarrhythmia, and ventricular tachycardia and the subsequent risk of relevant major cardiovascular events (MACE). METHODS AND RESULTS: The study included the 268 patients without a history of AF. All patients received an implantable cardiac monitor (ICM) and were followed for 2 years. The choice of revascularization was made by the treating team independently of the trial and retrospectively divided into pPCI, subacute PCI, primary thrombolysis, or no revascularization. Endpoints were new-onset arrhythmia and MACE.A total of 77 patients received no revascularization, whereas 49 received thrombolysis only and 142 received any PCI. The adjusted hazard ratio (HR) for developing any arrhythmia and the subsequently risk of MACE were increased in non-revascularized or thrombolysed patients compared with PCI-patients (any arrhythmia, non-revascularization: HR = 1.7, P = 0.01 and thrombolysis: HR = 1.6, P = 0.05; MACE, non-revascularization: HR = 3.1, P = 0.05 and thrombolysis: HR = 3.1, P = 0.08). All HRs were adjusted for significant baseline and clinically considered covariates and stratified for calendar year. CONCLUSION: This study is the first to demonstrate that the long-term risk of arrhythmia documented by an ICM and the subsequent risk of MACE were increased in non-revascularized or thrombolysed patients compared with PCI-patients in a post-MI population with LVEF <40%.

Cardiac arrhythmias in critically ill patients with coronavirus disease 2019: A retrospective population-based cohort study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) may be associated with cardiac arrhythmias in hospitalized patients, but data from the ICU setting are limited. We aimed to describe the epidemiology of cardiac arrhythmias in ICU patients with COVID-19. METHODS: We conducted a multicenter, retrospective cohort study including all ICU patients with an airway sample positive for severe acute respiratory syndrome corona-virus 2 from March 1st to June 1st in the Capital Region of Denmark (1.8 million inhabitants). We registered cardiac arrhythmias in ICU, potential risk factors, interventions used in ICU and outcomes. RESULTS: From the seven ICUs we included 155 patients with COVID-19. The incidence of cardiac arrhythmias in the ICU was 57/155 (37%, 95% confidence interval 30-45), and 39/57 (68%) of these patients had this as new-onset arrhythmia. Previous history of tachyarrhythmias and higher disease severity at ICU admission were associated with cardiac arrhythmias in the adjusted analysis. Fifty-four of the 57 (95%) patients had supraventricular origin of the arrhythmia, 39/57 (68%) received at least one intervention against arrhythmia (eg amiodarone, IV fluid or magnesium) and 38/57 (67%) had recurrent episodes of arrhythmia in ICU. Patients with arrhythmias in ICU had higher 60-day mortality (63%) as compared to those without arrhythmias (39%). CONCLUSION: New-onset supraventricular arrhythmias were frequent in ICU patients with COVID-19 and were related to previous history of tachyarrhythmias and severity of the acute disease. The mortality was high in these patients despite the frequent use of interventions against arrhythmias.

Death with an implantable cardioverter-defibrillator: a MADIT-II substudy.

AIMS: There are limited data regarding factors that identify implantable cardioverter-defibrillator (ICD) patients who will experience either ventricular tachyarrhythmic (VTA) or non-arrhythmic (NA) mortality, and the commonly used clinical classification of sudden cardiac death (SCD) vs. non-sudden cardiac death (NSCD) may not be accurate enough. We aimed to correlate clinical adjudication of mortality events to device interrogation data and to identify risk factors for VTA mortality in Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). METHODS AND RESULTS: Of the 746 patients who received an ICD in MADIT-II, 44 died from cardiac causes and had available interrogation data at the time of death. Sudden cardiac death vs. NSCD was defined by an adjudication committee. Ventricular tachyarrhythmic and NA arrhythmic deaths were categorized by the presence or absence of ventricular tachycardia or fibrillation (VT/VF) during the terminal event. Mode of death was found to be inaccurate when validated by device interrogation for VTA events: 50% patients adjudicated as SCD did not have a VTA event at the time of death; and 25% of adjudicated NSCD were found to have VT/VF during the mortality event. Multivariate analysis showed that factors independently associated with VTA mortality included: VT/VF >72 h prior to the mortality event [hazard ratio (HR) 8.0; P < 0.001], hospitalization for heart failure (HR 6.7; P = 0.001), and a history of hypertension (HR 4; P = 0.04). CONCLUSION: Current classification of SCD vs. NSCD fails to identify VTA events at the time of death in a significant proportion of patients, and simple clinical parameters can be used to identify ICD recipients with increased risk for VTA mortality.

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. Multivariable Cox models were used to assess the risk of appropriate ICD therapy and mortality in patients with and without cancer at time of implantation. During a median follow-up of 2.1 years, 2935 primary prevention ICD and 2730 secondary prevention ICD implantations were identified. Out of these [289 (5.1%)] had pre-existing cancer [primary 140 (4.8%), secondary 149 (5.5%)]. No differential risk for appropriate ICD therapy was found between patients with or without cancer, [primary cancer: 19/140, no cancer: 380/2795, hazard ratio (HR) = 1.07 (0.67-1.69)] and [secondary cancer: 42/149, no cancer: 699/2581, HR = 1.28 (0.93-1.75)]. In primary patients, cancer was not associated with higher risk of 1-year [cancer: 10/140, no cancer: 133/2795, HR = 1.20 (0.84-2.28)] or all-time mortality [cancer: 22/140, no cancer: 339/2795, HR = 1.13 (0.74-1.75)]. In secondary patients, cancer was associated with a higher 1-year [cancer: 19/149, no cancer: 108/2581, HR = 2.62 (1.60-4.29)] and all-time mortality [cancer: 44/149, no cancer: 315/2581, HR = 2.36 (1.71-3.24)]. CONCLUSION: Implantable cardioverter-defibrillators were implanted in a minority of cancer patients. No difference in risk of appropriate therapy was observed between cancer and non-cancer patients, regardless of implant indication. Cancer was associated with increased mortality in secondary prevention ICD patients, but not in primary prevention ICD patients. In secondary prevention ICD patients, the majority of deaths were attributable to cancer.

Transmission and loss of ECG snapshots: Remote monitoring in implantable cardiac monitors.

INTRODUCTION: Remote monitoring including transmission of electrocardiogram (ECG) strips has been implemented in implantable cardiac monitors (ICM). We appraise whether the physician can rely on remote monitoring to be informed of all possibly significant arrhythmias. METHODS: We analyzed remote monitoring transmissions of patients in the ongoing BIO|GUARD-MI study, in which Biotronik devices are used. Once per day, the devices automatically transmit messages with up to six ECG snapshots to the Home Monitoring Service Center. If more than one type of arrhythmia is recorded during a day, at least one ECG of each arrhythmia type is transmitted. RESULTS: 212 study patients were registered at the service center. The mean age of the patients was 70 ±â€¯8 years, and 74% were male. Patients were followed for an average of 13 months. The median time from device implantation until the first message receipt in the service center was 2 days. The median patient-individual transmission success was 98.0% (IQR 93.6-99.8) and remained stable in the second and third year. The most frequent arrhythmias were atrial fibrillation, bradycardia and high ventricular rate. 17.3% of the messages with ECG snapshots contained more than one arrhythmia type. DISCUSSION: Our analysis confirms that the physician can rely on Home Monitoring to be informed of all possibly significant arrhythmias during long-term follow-up. We have found hints that the transmission of only one episode per day may lead to the loss of clinically relevant information if patients with ICMs are followed by remote monitoring only.

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. According to guideline recommendations, we defined target daily doses as ≥50 mg carvedilol and ≥200 mg metoprolol. Prior to implantation 2427 of 2935 (83%) patients received beta-blocker therapy, with 2166 patients (89%) having initiated treatment 3 months or more prior to implantation. The majority of patients was prescribed carvedilol (52%) or metoprolol (41%). Patients on carvedilol reached target dosages more frequently than patients on metoprolol, with 39% of patients on carvedilol and 26% of patients on metoprolol at the time of implantation (P < 0.001 for all time-points). Increase in proportion of patients reaching target daily doses was observed for both carvedilol and metoprolol after ICD implantation. Carvedilol treatment was a strong predictor for being on target dose of BB at time of implant, as was treatment with angiotensin-converting enzyme inhibitors and/or spironolactone, no history of myocardial infarction, younger age and less pronounced heart failure symptoms. Conclusion: In a real-life setting of primary prevention ICD patients, 39% and 26% of patients were titrated to optimal target dose of carvedilol or metoprolol prior to implantation. A higher proportion of patients on carvedilol reached target dose, as compared with metoprolol.

Higher burden of supraventricular ectopic complexes early after catheter ablation for atrial fibrillation is associated with increased risk of recurrent atrial fibrillation.

Aims: Early identification of patients who could benefit from early re-intervention after catheter ablation is highly warranted. Our aim was to investigate the association between post-procedural burden of supraventricular ectopic complexes (SVEC) and the risk of long-term atrial fibrillation (AF) recurrence. Methods and results: A total of 125 patients undergoing catheter ablation for AF were included. Patients underwent 7-day Holter recordings immediately post-procedural. The number of SVEC in post-procedural Holter recordings was categorized into quartiles: 0-72, 73-212, 213-782 and ≥ 783 SVEC/day. Long-term AF recurrence was defined as a combined endpoint of AF ≥ 1 min during follow-up Holter recordings, cardioversion or hospitalization for AF after a 3-month blanking period and within 24 months of follow-up. High post-procedural supraventricular ectopy burden was associated with an increased risk of long-term AF recurrence in a dose-dependent manner (≥ 783 SVEC: HR 4.6 [1.9-11.5], P < 0.001) irrespective of AF recurrence during the blanking period or other risk factors. In patients with early AF recurrence < 90 days after catheter ablation ectopy burden was also highly predictive of long-term AF recurrence (SVEC ≥ 213: HR 3.0 [1.3-6.7], P = 0.007). Correspondingly, patients with early AF recurrence but low ectopy burden remained at low risk of long-term AF recurrence after the blanking period. Conclusion: Our results indicate that post-procedural ectopy burden is highly associated with long-term AF recurrence and could be a potent risk marker for selection of patients for early re-ablation. Development of future ablation risk stratification and strategies should include focus on post-procedural ectopy burden.

Driving following defibrillator implantation: development and pilot results from a nationwide questionnaire.

BACKGROUND: Implantable cardioverter defibrillator (ICD) implantation is associated with driving restrictions which may have profound effects on the patient's life. However, there is limited patient-reported data on the information given about driving restrictions, the adherence to the restrictions, the incidence of arrhythmic symptoms while driving, and the driving restrictions' effect on ICD patients' daily life and quality of life factors. A specific questionnaire was designed to investigate these objectives, intended for use in a nationwide ICD cohort. METHODS: The conceptual framework based on literature review and expert opinion was refined in qualitative semi-structured focus group interviews with ten ICD patients. Content validity was pursued through pre-testing, including expert review and 28 cognitive interviews with patients at all ICD implanting centres in Denmark. Finally, the Danish Pacemaker and ICD registry was used to randomly select 50 ICD patients with a first-time implantation between January 1, 2013 and November 30, 2016 for pilot testing, followed by a test-retest on 25 respondents. Test-retest agreement was assessed using kappa statistics or intraclass correlation coefficients. RESULTS: The pilot test achieved a response rate of 78%, whereof the majority were web-based (69%). Only 49% stated they had been informed about any driving restrictions after ICD implantation, whereas the number was 75% after appropriate ICD shock. Among respondents, 95% had resumed private driving, ranging from 1 to 90 days after ICD implantation. In those informed of a significant (≥ 1 month) driving ban, 55% stated the driving restrictions had impeded with daily life, especially due to limitations in maintaining employment or getting to/from work and 25% admitted they had knowingly been driving during the restricted period. There were six episodes of dizziness or palpitations not necessitating stopping the vehicle. Test-retest demonstrated good agreement of questionnaire items, with 69% of Kappa coefficients above 0.60. CONCLUSIONS: We have developed a comprehensive questionnaire on ICD patients' perspective on driving. Pre-testing and pilot testing demonstrated good content validity, feasible data collection methods, and a robust response rate. Thus, we believe the final questionnaire, distributed to almost 4000 ICD patients, will capture essential evidence to help inform driving guidelines in this population.

Postimplantation ventricular ectopic burden and clinical outcomes in cardiac resynchronization therapy-defibrillator patients: a MADIT-CRT substudy.

BACKGROUND: Frequent ventricular ectopy on preimplantation Holter has been associated with attenuated benefit from cardiac resynchronization therapy (CRT). However, it is unclear whether ectopic burden measured post-CRT implantation can be utilized to evaluate long-term prognosis. We aimed to describe the association between post-CRT implantation ectopic burden and subsequent risk of clinical outcomes. METHODS: At the 12-month follow-up visit, 24-hour Holter recordings were performed in 698 CRT-D patients from the MADIT-CRT study. The mean number of ventricular premature complexes (VPCs/hour) was calculated. High ectopic burden was defined as >10 VPCs/hour and low burden as ≤10 VPCs/hour. Multivariate Cox proportional hazards models were utilized to assess the association between 12-month ectopic burden and the risk of the end points of heart failure (HF) or death and ventricular tachyarrhythmias (VT/VF). RESULTS: At 12 months, 282 (40%) patients presented with low ectopic burden and 416 (60%) patients presented with high ectopic burden. The 3-year risk of HF/death and VT/VF was lower in patients with a low burden (7% and 8%) and significantly higher (25% and 24%) in patients with high burden. In multivariate analyses, patients with a high ectopic burden had approximately threefold increased risk of both HF/death (HR=2.76 [1.62-4.70], p < .001) and VT/VF (HR=2.79 [1.69-4.58], p < .001). CONCLUSION: In CRT-D patients with mild heart failure, high ectopic burden at 12-month follow-up was associated with a high 3-year risk of HF/death and VT/VF and threefold increased risk as compared to patients with low burden. Ectopic burden at 12 months may be a valuable approach for evaluating long-term prognosis.