Right Ventricular Free Wall Strain and Effect of Defibrillator Implantation in Patients With Nonischemic Systolic Heart Failure.

BACKGROUND: Patients with nonischemic systolic heart failure have an increased risk of malignant ventricular arrhythmias and sudden cardiovascular death. Because the risk is less pronounced than for patients with ischemic cause of heart failure more discriminating tools are needed to identify patients most likely to benefit from implantable cardioverter-defibrillator (ICD) implantation. Right ventricular (RV) dysfunction is associated with a worse prognosis, but whether RV free wall strain (RV-FWS) measured with echocardiography can identify the patients most likely to benefit from ICD implantation is not known. METHODS AND RESULTS: In this extended follow-up analysis of the Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality (DANISH) trial, RV-FWS was measured with echocardiography in 445 patients before randomization. RV dysfunction was defined as an RV-FWS of greater than -20%. The primary end point was all-cause mortality. The median RV-FWS was -18% (quartiles -23% to -14%), and RV dysfunction was measured in 255 patients (57%). During a median follow-up of 5.7 years, 170 patients (38%) died. There was a statistically significant interaction between RV dysfunction and the effect of ICD implantation (P = .003), also after adjusting for known cardiovascular risk factors (P = .01). ICD implantation significantly decreased all-cause mortality in patients with RV dysfunction (hazard ratio 0.54, 95% confidence interval 0.36-0.80, P = .002), but not in patients with normal RV function (hazard ratio 1.34, 95% confidence interval 0.84-2.12, P = .22). CONCLUSIONS: In patients with nonischemic systolic heart failure, RV dysfunction on echocardiography was associated with a greater effect of ICD implantation and could be used to select patients with benefit from ICD treatment.

Risk factors for cardiac implantable electronic device infections: a nationwide Danish study.

AIMS: Cardiac implantable electronic device (CIED) infection is a severe complication to modern management of cardiac arrhythmias. The CIED type and the type of surgery are recognized as risk factors for CIED infections, but knowledge of patient-related risk factors is scarce. This study aimed to identify lifelong patient-related risk factors for CIED infections. METHODS AND RESULTS: Consecutive Danish patients undergoing a CIED implantation or reoperation between January 1996 and April 2018 were included. The cohort consisted of 84 429 patients undergoing 108 494 CIED surgeries with a combined follow-up of 458 257 CIED-years. A total of 1556 CIED explantations were classified as either pocket (n = 1022) or systemic CIED infection (n = 534). Data were cross-linked with records from the Danish National Patient Registry and the Danish National Prescription Registry. Using multiple-record and multiple-event per subject proportional hazard analysis, specific patient-related risk factors were identified but with several variations amongst the subtypes of CIED infection. CIED reoperations were associated with the highest risk of pocket CIED infection but also CIED type, young age, and prior valvular surgery [hazard ratio (HR): 1.62, 95% confidence interval (CI): 1.29-2.04]. Severe renal insufficiency/dialysis (HR: 2.40, 95% CI: 1.65-3.49), dermatitis (HR: 2.80, 95% CI: 1.92-4.05), and prior valvular surgery (HR: 2.09, 95% CI: 1.59-2.75) were associated with the highest risk of systemic CIED infections. Congestive heart failure, ischaemic heart disease, malignancy, chronic obstructive pulmonary disease, and temporary pacing were not significant at multivariate analysis. CONCLUSION: Specific comorbidities and surgical procedures were associated with a higher risk of CIED infections but with variations amongst pocket and systemic CIED infection. Pocket CIED infections were associated with CIED reoperations, young age and more complex type of CIED, whereas systemic CIED infections were associated with risk factors predisposing to bacteraemia.

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.

Anxiety and depression symptoms in Danish patients with an implantable cardioverter-defibrillator: prevalence and association with indication and sex up to 2 years of follow-up (data from the national DEFIB-WOMEN study).

AIMS: To investigate (i) the prevalence of anxiety and depression and (ii) the association between indication for implantable cardioverter-defibrillator (ICD) implantation and sex in relation to anxiety and depression up to 24 months' follow-up. METHODS AND RESULTS: Patients with a first-time ICD, participating in the national, multi-centre, prospective DEFIB-WOMEN study (n = 1496; 18% women) completed the Hospital Anxiety and Depression Scale at baseline, 3, 6, 12, and 24 months. Data were analysed using linear mixed modelling for longitudinal data. Patients with a secondary prophylactic indication (SPI) had higher mean anxiety scores than patients with a primary prophylactic indication (PPI) at baseline, 3, and 12 months and higher mean depression scores at all-time points, except at 24 months. Women had higher mean anxiety scores as compared to men at all-time points; however, only higher mean depression scores at baseline. Overall, women with SPI had higher anxiety and depression symptom scores than men with SPI. Symptoms decreased over time in both women and men. From baseline to follow-up, the prevalence of anxiety (score ≥8) was highest in patients with SPI (13.3-20.2%) as compared to patients with PPI (range 10.0-14.7%). The prevalence of depression was stable over the follow-up period in both groups (range 8.5-11.1%). CONCLUSION: Patients with a SPI reported higher anxiety and depression scores as compared to patients with PPI. Women reported higher anxiety scores than men, but only higher depression scores at baseline. Women with SPI reported the highest anxiety and depression scores overall.

Long-term follow-up of abandoned transvenous defibrillator leads: a nationwide cohort study.

AIMS: Commonly, a dysfunctional defibrillator lead is abandoned and a new lead is implanted. Long-term follow-up data on abandoned leads are sparse. We aimed to investigate the incidence and reasons for extraction of abandoned defibrillator leads in a nationwide cohort and to describe extraction procedure-related complications. METHODS AND RESULTS: All abandoned transvenous defibrillator leads were identified in the Danish Pacemaker and ICD Register from 1991 to 2019. The event-free survival of abandoned defibrillator leads was studied, and medical records of patients with interventions on abandoned defibrillator leads were audited for procedure-related data. We identified 740 abandoned defibrillator leads. Meantime from implantation to abandonment was 7.2 ± 3.8 years with mean patient age at abandonment of 66.5 ± 13.7 years. During a mean follow-up after abandonment of 4.4 ± 3.1 years, 65 (8.8%) abandoned defibrillator leads were extracted. Most frequent reason for extraction was infection (pocket and systemic) in 41 (63%) patients. Procedural outcome after lead extraction was clinical success in 63 (97%) patients. Minor complications occurred in 3 (5%) patients, and major complications in 1 (2%) patient. No patient died from complication to the procedure during 30-day follow-up after extraction. CONCLUSION: More than 90% of abandoned defibrillator leads do not need to be extracted during long-term follow-up. The most common indication for extraction is infection. Abandoned defibrillator leads can be extracted with high clinical success rate and low risk of major complications at high-volume centres.

Incidence of device-related infection in 97 750 patients: clinical data from the complete Danish device-cohort (1982-2018).

AIMS: Device-related infection (DRI) is a severe complication to cardiac implantable electronic devices (CIED) therapy. Device-related infection incidence and its risk factors differ between previous studies. We aimed to define the long-term incidence and incidence rates of DRI for different types of CIEDs in the complete Danish device-cohort and identify patient-, operation- and device-related risk factors for DRI. METHODS AND RESULTS: From the Danish Pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Register, we included consecutive Danish patients undergoing CIED implantation or reoperation from January 1982 to April 2018, resulting in 97 750 patients, 128 045 operations and follow-up of in total 566 275 device years (DY). We identified 1827 DRI causing device removals. Device-related infection incidence during device lifetime was 1.19% (1.12-1.26) for PM, 1.91% (1.71-2.13) for ICD, 2.18% (1.78-2.64) for cardiac resynchronization therapy (CRT)-pacemakers (CRT-P), and 3.35% (2.92-3.83) for CRT-defibrillators (CRT-D). Incidence rates in de novo implantations were 2.04/1000 DY for PM, 3.84 for ICD, 4.38 for CRT-P, and 6.76 for CRT-D. Using multiple-record and multiple-event per subject proportional hazard analysis, we identified implantation of complex devices (ICD and CRT), reoperations, prior DRI, male sex, and younger age as significantly associated with higher DRI risk. CONCLUSION: Overall risk of infection was low in PM implantations but considerably higher in CRT systems and after reinterventions. These data support the importance of evaluating all patients considered for CIED therapy thoroughly, in order to identify potential modifiable risk factors and reduce the risk of early reoperations.

Association between implantable cardioverter-defibrillator therapy and different lead positions in patients with cardiac resynchronization therapy.

Aims: To evaluate the impact of different right and left ventricular lead positions (RV-LP and LV-LP) on the risk of therapy for ventricular tachycardia/ventricular fibrillation in patients with a cardiac resynchronization therapy device (CRT-D). Methods and results: We performed a large nationwide cohort study on patients in Denmark receiving a CRT-D device from 2008 to 2012 from the Danish Pacemaker and implantable cardioverter defibrillator (ICD) registry. Lead positions were registered during the implantation and categorized as anterior/lateral/posterior and basal/mid-ventricular/apical for the LV-LP, and as apical/non-apical for the RV-LP. Appropriate and inappropriate therapies were registered during follow-up via remote monitoring or at device interrogations. Time to event was summarized with Kaplan-Meier plots, and competed risk regression analysis was used to calculate adjusted hazard ratios (aHR) with 95% confidence intervals (CI). Following variables were included in the analysis: gender, age, heart failure aetiology, New York heart association class, left ventricular ejection fraction, QRS duration, indication (secondary or primary prophylactic), RV-LP, LV-LP, and antiarrhythmic therapy. We included 1643 patients [mean age 68 (±10) years, 1343 (83%) men]. After a mean of 2.0 years, 322 (20%) patients received appropriate and 66 (4%) patients received inappropriate therapy. The aHR for appropriate therapy with a non-apical RV-LP was 0.70 95% CI (0.55-0.87, P = 0.002) as compared with an apical. We observed no significant association between appropriate therapy and LV-LP in left anterior oblique or right anterior oblique views or inappropriate therapy between any lead positions. Conclusion: An apical RV-LP is associated with an increased risk of appropriate therapy for ventricular tachyarrhythmia in patients with a CRT-D device.

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. All MRIs were performed with the PMs in asynchronous mode and without additional monitoring. There were no adverse events registered among the PM patients during the study period. The only statistically significant change after MRI scans was a small, but clinically insignificant increase in atrial sense. No occurrences of reprogramming to power-on-reset were registered. CONCLUSION: It is possible to perform MRI scans relatively safely in PM patients without additional monitoring or change in the normal MRI protocol, given that the PM has been assessed and reprogrammed prior to MRI. This is especially important to remember in the acute setting where MRI scans may be delayed when monitoring facilities are unavailable.

A Randomized Trial of His Pacing Versus Biventricular Pacing in Symptomatic HF Patients With Left Bundle Branch Block (His-Alternative).

OBJECTIVES: This study sought to compare 2 ways of achieving cardiac resynchronization. BACKGROUND: Cardiac resynchronization therapy (CRT) in patients with symptomatic heart failure and left bundle branch block (LBBB) can be achieved with His-bundle pacing correcting the bundle branch block (His-CRT). The present study is the largest randomized study comparing His-CRT and biventricular pacing (BiV-CRT) to date. METHODS: Fifty patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and LBBB according to electrocardiography were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group. RESULTS: His-corrective pacing was achieved in 72% of the patients in the His-CRT group. Intention-to-treat 6-month follow-up LVEF increased by 16 ± 7% in the His-CRT group compared with 13 ± 6% in the BiV-CRT group (nonsignificant) and improvements were seen in clinical and physical parameters in both treatment arms with no significant differences between the groups. Pacing thresholds were higher for His-CRT compared with BiV-CRT both at implantation (1.8 ± 1.2 V vs. 1.2 ± 0.8 V; p < 0.01) and at 6-month follow-up (2.3 ± 1.4 V vs. 1.4 ± 0.5 V; p < 0.01). The per-protocol LVEF was significantly higher at 6 months (48 ± 8% vs. 42 ± 8%; p < 0.05) and the end-systolic volume was lower (65 ± 22 ml vs. 83 ± 27 ml; p < 0.05) in His-CRT patients compared with BiV-CRT. CONCLUSIONS: In heart failure patients with LBBB, His-CRT provided similar clinical and physical improvement compared with BiV-CRT at the expense of higher pacing thresholds.

Significant regional variation in use of implantable cardioverter-defibrillators in Denmark.

AIMS: Implantable cardioverter-defibrillator (ICD) treatment prevents sudden cardiac death in high-risk patients. This study examined geographical variation in ICD implantation rates in Denmark and potential causes of variation. METHODS AND RESULTS: We obtained numbers of ICD implantations in the 5 Danish regions and 98 municipalities during 2007-13 from the Danish Pacemaker and ICD Registry. Standardized implantation rates (SIRs) were computed as ICD implantations per 1 000 000 person-years, and age- and gender-standardized to the Danish population. We examined associations of the municipal SIR with mean age and Charlson Comorbidity Index score of ICD recipients, percentage of implantations with primary prophylactic indication, and distance from patient residency to ICD implanting centre. Based on 7192 ICD implantations, the nationwide SIR was 186 [95% confidence interval (CI) 182-190], ranging from 170 (95% CI 158-183) in the North Denmark Region to 206 (95% CI 195-218) in the Region of Zealand. Municipalities with higher patient comorbidity scores, higher percentages of implantations with primary prophylactic indication, and shorter distances to ICD implanting centres, had higher SIRs [differences between SIRs of municipalities in highest and lowest quartiles 22 (95% CI 10-34), 45 (95% CI 33-58), and 35 (95% CI 24-47), respectively]. Regional differences in SIRs decreased over time and had become insignificant during 2011-13. CONCLUSION: Implantable cardioverter-defibrillator implantation rates in Denmark varied significantly between regions but variation decreased during 2007-13. Geographical variation was associated with differences in patient comorbidity score, variation in use of primary prophylactic ICD treatment, and distance to ICD implanting centre.