Age-stratified clinical outcome in patients with known heart failure who receive pacemaker-, resynchronization therapy- or defibrillator implants.

Introduction Patients with heart failure (HF) and bradycardia may be eligible for different types of cardiac implantable electronic devices (CIED), depending on presence of AV conduction disease, age and comorbidities. We aimed to assess prognosis for these patients, after CIED implantation, stratified for type of CIED device. Methods All patients with preexisting HF diagnosis who received a CIED with a right ventricular lead during the period 2005-2018 in Sweden were identified via the Pacemaker-registry. Data was crossmatched with the population registry and national disease registries. Outcome was 5-year risk of HF hospitalization, and mortality. Results 37745 patients were included in the study. Comparing demographics for ICD vs. pacemaker implants, median age was 66 years vs. 83 years, 20% vs. 41% were female, 64% vs. 50% had ischemic heart disease and 35% vs. 67% had atrial fibrillation (all p<0,001). 5-year mortality was highest in single-chamber pacemaker recipients (61% compared to average 40%, p<0.001) but proportion of cardiovascular mortality was highest for CRT recipients (68% vs 63% p<0.001). Adjusted mortality was higher for pacemaker-patients in all age decile groups (ranging from <60 to >90 years old, all p<0.001). HF hospitalization occurred in 28% (dual-chamber pacemaker) to 39% (CRT-P) of patients, and cause of death was HF in 15% (dual-chamber pacemaker) to 25% (CRT-D), all p<0.001. Conclusion In this large real-world cohort of CIED treated patients with prior heart failure, demography- and mortality-data indicate that clinicians chose devices according to the overall status of the patient. Heart failure related events occurred in all groups, but were more common in CRT-treated patients.

Early ICD implantation following out-of-hospital cardiac arrest: a retrospective cohort study from the Swedish Registry for Cardiopulmonary Resuscitation.

BACKGROUND: It is unclear whether an implantable cardioverter-defibrillator (ICD) is generally beneficial in survivors of out-of-hospital cardiac arrest (OHCA). OBJECTIVE: We studied the association between ICD implantation prior to discharge and survival in patients with cardiac aetiology or initial shockable rhythm in OHCA. DESIGN: We conducted a retrospective cohort study in the Swedish Registry for Cardiopulmonary Resuscitation. Treatment associations were estimated using propensity scores. We used gradient boosting, Bayesian additive regression trees, neural networks, extreme gradient boosting and logistic regression to generate multiple propensity scores. We selected the model yielding maximum covariate balance to obtain weights, which were used in a Cox regression to calculate HRs for death or recurrent cardiac arrest. PARTICIPANTS: All cases discharged alive during 2010 to 2020 with a cardiac aetiology or initial shockable rhythm were included. A total of 959 individuals were discharged with an ICD, and 2046 were discharged without one. RESULTS: Among those experiencing events, 25% did so within 90 days in the ICD group, compared with 52% in the other group. All HRs favoured ICD implantation. The overall HR (95% CI) for ICD versus no ICD was 0.38 (0.26 to 0.56). The HR was 0.42 (0.28 to 0.63) in cases with initial shockable rhythm; 0.18 (0.06 to 0.58) in non-shockable rhythm; 0.32 (0.20 to 0.53) in cases with a history of coronary artery disease; 0.36 (0.22 to 0.61) in heart failure and 0.30 (0.13 to 0.69) in those with diabetes. Similar associations were noted in all subgroups. CONCLUSION: Among survivors of OHCA, those discharged with an ICD had approximately 60% lower risk of death or recurrent cardiac arrest. A randomised trial is warranted to study this further.

Sex-based differences in cardiac resynchronization therapy upgrade and outcome for patients with pacemaker and new-onset heart failure.

BACKGROUND: Patients with chronic right ventricular (RV) pacing are at an increased risk of heart failure. Previous studies have indicated that cardiac resynchronization therapy (CRT) is underused in this setting, and that there may be sex-based differences in both CRT use and clinical outcome. OBJECTIVE: To evaluate sex-based differences in CRT use and clinical outcome for patients with new-onset heart failure post RV pacing. METHODS: Data from the Swedish pacemaker registry was matched with data from the national death and disease registries. Patients with de novo pacemaker implant due to AV block during the period 2005-2020 were included. New-onset heart-failure within two years post-implant was evaluated, primary outcome was all-cause mortality. RESULTS: In all, 30183 patients (37% female) were included. Women were on average 3 years older, but had less comorbidities than men. Median follow-up time was 4.5 [2.0-8.0] years. Women had better age- and comorbidity-adjusted survival (HR 0.78 [0.73-0.84], p < .001). For the 3560 patients (12.4% men and 10.7% women, p < .001) who were diagnosed with new-onset heart failure, 5-year mortality was similar for men and women (50% vs. 48%, p = .29). However, women were less likely to receive CRT-upgrade (3.8% vs. 9.1%, p < .001), and those who did were almost ten years younger than the men. CONCLUSION: Women with pacemaker due to AV block are older but have less comorbidities than men. They are less likely to develop new-onset heart failure, but also less likely to receive a CRT upgrade if they do develop heart failure. Increased awareness of the positive effects of CRT upgrade and potential sex- and age-based discrimination is warranted.

Age-stratified comparison of prognosis in cardiac resynchronization therapy with or without prophylactic defibrillator for nonischemic cardiomyopathy-a nationwide cohort study.

AIMS: Prior studies have suggested that the benefit from primary preventive defibrillator treatment for patients with nonischemic cardiomyopathyy, treated with cardiac resynchronization therapy, may be age-dependent. We aimed to compare age-stratified mortality rates and mode of death in patients with nonischemic cardiomyopathy who are treated with either primary preventive cardiac resynchronization therapy with defibrillator (CRT-D) or CRT with pacemaker (CRT-P). METHODS AND RESULTS: All patients with nonischemic cardiomyopathy and CRT-P or primary preventive CRT-D who were implanted in Sweden during the period 2005-2020 were included. Propensity scoring was used to create a matched cohort. Primary outcome was all-cause mortality within 5 years. In all, 4027 patients were included: 2334 with CRT-P and 1693 with CRT-D. Crude 5-year mortality was 635 (27%) vs. 246 (15%), P < 0.001. In Cox regression analysis, adjusted for clinically relevant covariables, CRT-D was independently associated with higher 5-year survival [0.72 (0.61-0.85), P < 0.001]. Cardiovascular mortality was similar between groups (62 vs. 64%, P = 0.64), but death from heart failure was more common in the CRT-D group (46 vs. 36%, P = 0.007). In the matched cohort (n = 2414), 5-year mortality was 21% (24 vs. 16%, P < 0.001). In age-stratified analyses, CRT-P was associated with higher mortality in age groups <60 years and 70-79 years, but there was no difference in age groups 60-69 years or 80-89 years. CONCLUSION: In this nationwide registry-based study, patients with CRT-D had better 5-year survival compared to patients with CRT-P. The interaction between age and mortality reduction was not consistent, but patients with CRT-D aged <60 years had the largest absolute mortality reduction.

Role of baseline 12­lead ECG in predicting syncope caused by arrhythmia in patients investigated using an implantable loop recorder.

AIM: To evaluate the role of baseline 12­lead ECG in predicting the syncope mechanism during continuous monitoring using an implantable loop recorder (ILR). METHODS: Consecutive patients with syncope implanted with an ILR were enrolled. Baseline 12­lead ECG were related to ECG diagnosis derived from ILR tracings recorded at the time of syncope recurrence. RESULTS: In total 300 patients with a mean age of 66 ±â€¯16 years were included, 49% (146/300) received an ILR-guided diagnosis during follow-up. Patients with abnormal baseline ECG more frequently received an ILR-guided diagnosis compared to those with normal baseline ECG 59% vs. 44%, p = 0.018. For a diagnosis of arrhythmic syncope, the corresponding frequencies were 45% vs. 26%, p = 0.001.Patients with bifascicular block significantly more common received an ILR-guided diagnosis 76% (25/33) compared to those with normal baseline ECG 44% (90/205), p ≪ 0.001. In this subgroup, 96% (24/25) were diagnosed with arrhythmic syncope, 23 of which were due to bradyarrhythmia. Bifascicular block occurred almost exclusively among those ≥60 years (31/33). After logistic regression the adjusted OR for arrhythmic syncope was significant for bifascicular block 5.5 (95%CI 2.3-13.2), p ≪ 0.001. PPV for bifascicular block in predicting arrhythmic syncope was 73% and NPV 73%. CONCLUSION: A baseline 12­lead ECG with bifascicular block was a strong predictor for syncope during follow-up, most often due to bradyarrhythmia caused by intermittent complete heart block. No other ECG findings were associated with the ILR outcome. We find it reasonable to consider permanent pacing instead of an ILR for patients with bifascicular block and unexplained syncope.

Stroke incidence and anticoagulation treatment in patients with pacemaker-detected silent atrial fibrillation.

BACKGROUND: Silent atrial fibrillation (AF) episodes are common but the role of anticoagulation treatment is under debate. METHODS: Consecutive patients with dual-chamber pacemakers for sinus node disease or AV block/bundle branch block were retrospectively enrolled and the development of silent AF, any anticoagulation and the incidence of ischaemic stroke and dementia were recorded. RESULTS: In total 411 patients without and 267 with known AF at implant were included. During a median follow-up of 38 months, 30% (125/411) of patients without known AF at implant were diagnosed with silent AF, 62% of those had or were prescribed anticoagulation. Heart failure (p = 0.03) and age >75 years (p = 0.0002) were risk markers for incident silent AF. In patients with known AF at implant, 80% (216/267) were on anticoagulation at implant. The annual stroke incidence was 2.1% in patients with known AF at implant, as compared to 1.9% in patients who developed silent AF during follow-up, and 1.4% in patients without AF. Vascular dementia developed in 11.2% and 6.2% respectively in patients with known AF versus no AF (p = 0.048) as well as in 5.6% of those with silent AF (p = 0.09). CONCLUSION: The stroke risk in our study population with an incident silent AF diagnosis may have been significantly decreased by the high proportion of anticoagulation treatment. This could imply that without this treatment the stroke risk might have been high enough to justify anticoagulation. Development of vascular dementia was twice as common among patients with known AF as compared to those witht silent AF or no AF. More data is needed to inform the optimal treatment for these patients.

Low rate of and rapid attention to inappropriate ICD shocks with remote device and rhythm monitoring: a qualitative study.

OBJECTIVES: Inappropriate shocks are unpleasant and painful. We hypothesise that remote monitoring and careful attention to known and incident atrial fibrillation (AF) can reduce inappropriate shocks to a very low level in clinical praxis. METHODS: Altogether 259 patients with implantable cardioverter defibrillator implanted for secondary (S, n=113) and primary (P, n=146) prevention were followed via remote monitoring. At implant, 42S (37%) and 54P (37%) patients had known AF. RESULTS: Inappropriate shocks, all but five due to AF, occurred in 7S (6.2%) and 11P (7.5%), and there were only inappropriate shocks in 5/7S and in 8/11P. They occurred in four of 42S (9.5%) with and in three of 71S (4.2%) without known AF, and in seven of 54P (13%) with and in four of 92P (4.3%) without known AF. The median time from shock to action was 5 and 1 day, respectively. Actions were medication with amiodarone, ß blockers, ß blockers+amiodarone or ß blockers+digoxin (n=5), ß blockers+insertion of an atrial lead (n=1), replacement of a fractured lead (n=2), reprogramming in combination with ß blockers, digoxin or amiodarone (n=4), reprogramming (n=2) and none (n=4). After action, four further inappropriate shocks occurred during more than 2 years of follow-up, all due to AF. CONCLUSIONS: Inappropriate shocks occurred at a low rate and most often because of AF known at implant. Remote monitoring enabled rapid action, after which few inappropriate shocks occurred over more than 2 years. Attention to known and incident AF was the most important action to reduce inappropriate shocks.

Is one month treatment with dabigatran before cardioversion of atrial fibrillation sufficient to prevent thromboembolism?

AIMS: The use of direct oral anticoagulants (DOACs) in patients undergoing elective direct current (DC) cardioversion of non-acute atrial fibrillation (AF) can potentially shorten the time from initiation of anticoagulation treatment to cardioversion, compared with warfarin. The safety of this strategy needs to be investigated. Data from subgroup analysis from clinical trials with DOAC do not clarify whether 4-week treatment with DOAC is sufficient to prevent thromboembolism (TE) after cardioversion. The aim of this retrospective study was to assess the incidence of TE in anticoagulant naive patients converted after one month's pre-treatment with dabigatran. METHODS AND RESULTS: We scrutinized the medical records of 631 patients where dabigatran had been used prior to elective DC cardioversion. Transoesophageal echocardiography was rarely performed. Thromboembolism within 30 days of cardioversion was the primary endpoint. A total of 570 patients were naive to OAC when dabigatran was initiated. The mean age in this group was 64.2 ± 11 years and 31.7% were women. The mean CHA2DS2-VASc score was 2.0 ± 1.5. The dose of dabigatran was 150 mg b.i.d. in 94% of the patients. The median time from initiation of dabigatran to cardioversion was 32.0 ± 15 days. In 91% cardioversion resulted in sinus rhythm. During the 30-day follow-up, three TE occurred for an incidence of 0.53% (0.18-1.54). CONCLUSION: In this retrospective study from clinical material, we found a low incidence of TE when dabigatran was used as TE prophylaxis in association with elective cardioversion. These results indicate that dabigatran is a safe alternative strategy to warfarin during cardioversion in patients with AF.