Associations between common ECG abnormalities and out-of-hospital cardiac arrest.

Background: Out-of-hospital cardiac arrest (OHCA) is often the first manifestation of unrecognised cardiac disease. ECG abnormalities encountered in primary care settings may be warning signs of OHCA. Objective: We examined the association between common ECG abnormalities and OHCA in a primary care setting. Methods: We cross-linked individuals who had an ECG recording between 2001 and 2011 in a primary care setting with the Danish Cardiac Arrest Registry and identified OHCAs of presumed cardiac cause. Results: A total of 326 227 individuals were included and 2667 (0,8%) suffered an OHCA. In Cox regression analyses, adjusted for age and sex, the following ECG findings were strongly associated with OHCA: ST-depression without concomitant atrial fibrillation (HR 2.79; 95% CI 2.45 to 3.18), left bundle branch block (LBBB; HR 3.44; 95% CI 2.85 to 4.14) and non-specific intraventricular block (NSIB; HR 3.15; 95% CI 2.58 to 3.83). Also associated with OHCA were atrial fibrillation (HR 1.89; 95% CI 1.63 to 2.18), Q-wave (HR 1.75; 95% CI 1.57 to 1.95), Cornell and Sokolow-Lyon criteria for left ventricular hypertrophy (HR 1.56; 95% CI 1.33 to 1.82 and HR 1.27; 95% CI 1.12 to 1.45, respectively), ST-elevation (HR 1.40; 95% CI 1.09 to 1.54) and right bundle branch block (HR 1.29; 95% CI 1.09 to 1.54). The association between ST-depression and OHCA diminished with concomitant atrial fibrillation (HR 1.79; 95% CI 1.42 to 2.24, p < 0.01 for interaction). Among patients suffering from OHCA, without a known cardiac disease at the time of the cardiac arrest, 14.2 % had LBBB, NSIB or ST-depression. Conclusions: Several common ECG findings obtained from a primary care setting are associated with OHCA.

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.

Remote monitoring and clinical outcomes: details on information flow and workflow in the IN-TIME study.

AIMS: Randomized clinical trials investigating a possible outcome effect of remote monitoring in patients with implantable defibrillators have shown conflicting results. This study analyses the information flow and workflow details from the IN-TIME study and discusses whether differences of message content, information speed and completeness, and workflow may contribute to the heterogeneous results. METHODS AND RESULTS: IN-TIME randomized 664 patients with an implantable cardioverter/defibrillator indication to daily remote monitoring vs. control. After 12 months, a composite clinical score and all-cause mortality were improved in the remote monitoring arm. Messages were received on 83.1% of out-of-hospital days. Daily transmissions were interrupted 2.3 times per patient-year for more than 3 days. During 1 year, absolute transmission success declined by 3.3%. Information on medical events was available after 1 day (3 days) in 83.1% (94.3%) of the cases. On all working days, a central monitoring unit informed investigators of protocol defined events. Investigators contacted patients with a median delay of 1 day and arranged follow-ups, the majority of which took place within 1 week of the event being available. CONCLUSION: Only limited data on the information flow and workflow have been published from other studies which failed to improve outcome. However, a comparison of those data to IN-TIME suggest that the ability to see a patient early after clinical events may be inferior to the set-up in IN-TIME. These differences may be responsible for the heterogeneity found in clinical effectiveness of remote monitoring concepts.

Disease progression after ablation for atrial flutter compared with atrial fibrillation: A nationwide cohort study.

AIMS: The aim of this study was to study the risk of death and development of arrhythmia and/or subsequently heart failure after an atrial flutter ablation procedure compared with an atrial fibrillation (AF) ablation procedure. METHODS: This observational study is based on data from Danish nationwide health databases. Patients with a first-time ablation procedure for either atrial flutter or AF in the period 2000-2016 were included. Rates of renewed arrhythmia, heart failure or death were compared and reported as adjusted hazard ratios (HR). RESULTS: The study population consisted of 2,004 and 3,803 patients with an incident atrial flutter or AF ablation procedure, respectively. All-cause mortality among atrial flutter patients was significantly higher compared with the AF group (HR 1.80, 95% confidence interval [CI] 1.39-2.35). The incidence of renewed arrhythmia without heart failure was lower in atrial flutter (HR 0.76, 95% CI 0.69-0.84). Renewed atrial flutter ablation and pacemaker implantations were significantly more frequent (HR 2.42, 95% CI 2.02-2.91 and HR 1.42, 95% CI 1.13-1.79, respectively) in atrial flutter compared with AF. The risk of heart failure was higher for atrial flutter, both after the initial ablation (HR 1.48, 95% CI 1.08-2.03), and after a further arrhythmia management event (HR 1.98, 95% CI 1.33-2.94). CONCLUSION: There was a higher mortality risk after atrial flutter ablation procedures compared with patients undergoing AF ablation. Rates of heart failure and further renewed (non-AF) arrhythmia management were higher in atrial flutter.

Atrial fibrillation in patients with severe mental disorders and the risk of stroke, fatal thromboembolic events and bleeding: a nationwide cohort study.

OBJECTIVES: Outcomes of atrial fibrillation (AF) in patients with severe mental disorders are largely unknown. We compared rates of stroke, fatal thromboembolic events and bleeding in patients with AF with and without mental disorders. DESIGN: Nationwide registry-based cohort study. SETTING: Denmark (population 5.6 million), 2000-2015. PARTICIPANTS: Patients with AF with schizophrenia (n=534), severe depression (n=400) or bipolar disease (n=569) matched 1:5 on age, sex and calendar time to patients with AF without mental disorders. EXPOSURE: Inpatient or hospital-based outpatient diagnosis of schizophrenia, severe depression or bipolar disease. PRIMARY AND SECONDARY OUTCOME MEASURES: HRs for stroke, fatal thromboembolic events and major bleeding comparing patients with and without mental disorders estimated by Cox regression with sequential adjustment for risk factors for stroke and bleeding, comorbidity and initiation of oral anticoagulant therapy (OAT). RESULTS: Compared with matched comparisons, crude 5-year HRs of ischaemic stroke were 1.37 (95% CI 0.88 to 2.14) for schizophrenia, 1.36 (95% CI 0.89 to 2.08) for depression and 1.04 (95% CI 0.69 to 1.56) for bipolar disease. After adjusting for risk factors, comorbidity and OAT, these HRs declined towards the null. Crude HRs of fatal thromboembolic events were 3.16 (95% CI 1.78 to 5.61) for schizophrenia, 1.31 (95% CI 0.67 to 2.56) for depression and 1.53 (95% CI 0.93 to 2.53) for bipolar disease. Rates of major bleeding were increased in patients with schizophrenia (crude HR 1.37, 95% CI 0.99 to 1.90) and severe depression (HR 1.25, 95% CI 0.87 to 1.78) but not bipolar disease (HR 0.82, 95% CI 0.58 to 1.15). CONCLUSION: Patients with AF with schizophrenia or severe depression experienced increased rates of stroke and major bleeding compared with matched comparisons. This increase was largely explained by differences in the prevalence of risk factors for stroke and bleeding, comorbidity and initiation of OAT during follow-up. Patients with AF with schizophrenia further experienced higher mortality following thromboembolic events than matched comparisons without mental disorders.

Venous thromboembolism in patients with implantable cardioverter-defibrillators.

AIMS: To examine the incidence of venous thromboembolism (VTE) and its risk factors among patients with implantable cardioverter-defibrillators (ICDs). METHODS AND RESULTS: All first-time ICD recipients in Denmark during 2000-12 were identified from medical databases. Incident VTEs were ascertained, overall and according to gender, age, Charlson Comorbidity Index score (no, moderate, or severe comorbidity), prior pacemaker or cardiac resynchronization therapy (CRT-D) implantation, and ICD type (single-chamber, dual-chamber, or CRT-D). We computed the risk of VTE within 3 months and 5 years of implantation, taking death into account as a competing risk. We used Cox proportional hazards regression to compute hazard ratios as estimates of incidence rate ratios (IRRs). Among 8132 ICD recipients, 136 VTEs were diagnosed during up to 13 years of follow-up (median = 3.0 years). The VTE incidence rate was thus 4.5 per 1000 person-years [95% confidence interval (CI): 3.7-5.2]. Venous thromboembolism risk was 0.3% (95% CIs ranging from 0.1 to 0.7%) within 3 months following ICD implantation regardless of comorbidity level. Within 5 years following implantation it was 1.4% (95% CI: 0.8-2.3%), 1.3% (1.0-1.8%), and 3.2% (95% CI: 2.4-4.1%) for patients with no, moderate, and severe comorbidity, respectively. Overall, severe comorbidity conferred a 2.7-fold higher incidence rate ratio than no comorbidity (95% CI: 1.6-4.6). Incidence rate ratios did not differ by gender, age, or ICD type. CONCLUSION: Three-month risk of VTE following ICD implantation was 0.3% regardless of comorbidity level. Five-year risk of VTE following ICD implantation was 1.9% and more than twice as high for patients with severe comorbidity as for patients without comorbidity.

Death and thrombo-embolic risk after ablation of atrial flutter compared with atrial fibrillation: a nationwide cohort study.

AIMS: The aim of this study was to investigate whether there is a similar mortality and thrombo-embolic risk, after an atrial ablation procedure, compared with an atrial fibrillation (AF) procedure. METHODS AND RESULTS: Using data from nationwide Danish health registries, we identified patients aged 18-75 years undergoing a first-time atrial flutter or an AF ablation procedure in the period 2000-13. Cox proportional hazards regression was used to calculate hazard ratios (HRs) after 5 years of follow-up, adjusting for concomitant risk factors. A total of 1096 and 2266 patients underwent an ablation for atrial flutter or AF, respectively. Age distribution was similar in the two, but atrial flutter patients had more co-morbidities. During 5 years of follow-up, we observed 38 and 36 deaths in the atrial flutter and AF groups, corresponding to an almost two-fold higher mortality rate among atrial flutter patients [crude HR 1.92, 95% confidence interval (CI) 1.22-3.03]. The higher mortality rate persisted after adjustment for age, sex, diabetes mellitus, and hypertension (adjusted HR 1.68, 95% CI 1.05-2.69). The rate of thrombo-embolic events was similar in the two groups (crude HR 1.34, 95% CI 0.71-2.56; adjusted HR 1.22, 95% CI 0.62-2.41). CONCLUSION: In this observational study, patients with atrial flutter had a significantly higher all-cause mortality rate compared with those with AF after an ablation procedure, but similar thrombo-embolic event rates. Future studies should elucidate the reason for this difference in mortality.

Atrial flutter and thromboembolic risk: a systematic review.

Atrial flutter confers a thromboembolic risk, but contrary to atrial fibrillation the relationship has only been addressed in few studies. This study performs an up to date systematic review of the literature to investigate the association between atrial flutter and thromboembolic events. Articles were found by MEDLINE, EMBASE search and a manual search of references list in included articles. International guidelines, meta-analyses, reviews, case reports, studies reporting thromboembolic events in relation to ablation, or cardioversion procedures, echocardiography, and observational studies were found eligible in this review. A total of 52 articles were included in this review. During cardioversion, thromboembolic event rates varied from 0% to 6% with a follow-up from 1 week to 6 years. Echocardiographic studies reported prevalence of thrombus material from 0% to 38% and a prevalence of spontaneous echo contrast (SEC) from 21% to 28%. One ablation study in non-anticoagulated patients reported thromboembolic events at 13.9%. Observational studies reported an overall elevated stroke risk (risk ratio 1.4, 95% CI 1.35 to 1.46) and mortality risk (HR 1.9, 95% CI 1.2 to 3.1) with long time follow-up compared with a control group in both studies. Given the limitations and heterogeneity of the data, a meta-analysis was not a part of this systematic review. Notwithstanding the limitations of observational studies and indirect data from echocardiographic studies, this systematic review confirms that clinical thromboembolic events, left atrial thrombus and SEC are highly prevalent in atrial flutter.

Thirteen-year nationwide trends in use of implantable cardioverter-defibrillators and subsequent long-term survival.

BACKGROUND: Long-term trends in use of implantable cardioverter-defibrillators (ICDs) and outcomes are rare. OBJECTIVE: We examined 13-year nationwide trends in ICD implantation and survival rates in Denmark. METHODS: Using medical databases, we identified all first time ICD recipients in Denmark during 2000-2012 (N = 8460) and ascertained all-cause mortality. We computed standardized annual implantation rates and mortality rate ratios according to age, sex, comorbidity level, indication, and device type. RESULTS: The standardized annual implantation rate increased from 42 per million persons in 2000 to 213 per million persons in 2012 (from 34 to 174 for men and from 8 to 39 for women). The increase was driven by secondary prophylactic ICDs until 2006 and primary prophylactic ICDs thereafter. The increase occurred particularly in older patients and those with a high level of comorbidity. Independent of indication, 76% of all patients with ICD were alive after 5 years. Men had a higher mortality rate compared with women (mortality rate ratio 1.28; 95% confidence interval 1.10-1.49). Compared with low comorbidity level, moderate, severe, and very severe comorbidity levels were associated with 1.6-, 2.5-, and 4.9-fold increased mortality rates, respectively. The most influential individual comorbidities were heart failure, diabetes, liver disease, and renal disease. CONCLUSION: The annual implantation rate of ICDs increased 5-fold in Denmark between 2000 and 2012. The rate increase occurred for both men and women, but particularly in the elderly and patients with severe comorbidity. Five-year survival probability was high, but severe comorbidity and male sex were associated with shorter survival.

The impact of drug discontinuation in patients treated with temporary pacemaker due to atrioventricular block.

INTRODUCTION: Patients treated with a temporary pacemaker (TPM) due to atrioventricular (AV) block are often monitored after discontinuation of AV node blocking drugs to evaluate the indication for permanent pacing. However, the impact of drug discontinuation is sparsely documented. We investigated to what extent drug discontinuation abolished the need for permanent pacemaker (PPM) implantation. METHODS AND RESULTS: All hospital records of patients who received a TPM at Aalborg Hospital, Denmark, between January 2000 and March 2011 (n = 575) were retrospectively reviewed. Patients with AV block who were treated with a TPM and concomitant cessation of drug therapy were included if there was no other underlying mechanism causing the AV block. AV blocking drugs included antiarrhythmic agents classes II-IV and digoxin. Fifty-five patients fulfilled our inclusion criteria. Forty-seven patients had an indication for a PPM at the initial hospital admission, despite drug discontinuation. Of the remaining 8 patients who were discharged without a PPM, 3 subsequently experienced events: 2 had recurrence of AV block requiring a PPM, and 1 experienced syncope. Thus, in total, 49 (89%) patients had a final indication for a permanent pacemaker (PPM). Of patients receiving beta-blocker monotherapy, 26 (96%) had an indication for a PPM. TPM implantation was complicated by infection or displacement in 11% of cases. CONCLUSIONS: The vast majority of patients treated with a TPM due to AV block and who receive beta-blockers alone or in combination with digoxin have a final indication for a PPM despite cessation of drug treatment. TPM are frequently associated with complications.

[Radiofrequency ablation as acute treatment of ventricular arrhythmia]. / Radiofrekvensablation som akut behandling af ventrikulære arytmier.

The role of radiofrequency ablation in the acute management of electrical storm is reviewed. Electrical storm is defined as three or more intervention-requiring episodes of ventricular fibrillation or ventricular tachycardia within 24 hours. The management of electrical storm includes antiarrhythmic therapy including beta blockers and correction of initiating causes as myocardial ischaemia and electrolyte disturbances. Radiofrequency ablation provides an alternative in the management of electrical storm in the case of failure of the medical therapy.

[Radiotherapy in patients with a pacemaker or an implantable cardioverter defibrillator]. / Stråleterapi hos patienter med pacemakere og implanterbare kardioverterdefibrillatorer.

With an ageing population an increasing number of patients with a pacemaker or implantable cardioverter defibrillator will present at radiotherapy units due to malignancy. Two separate questionnaires concerning routines of departments treating this population were sent to Danish implanting cardiology centers and to radiotherapy departments. Differences in the handling of these patients were found. Removal of the devices and monitoring of the patients is assessed on a highly individual basis. In the absence of updated official guidelines, departments treating these patients should produce local instructions.

[Constrictive pericarditis caused by carbergoline]. / Konstriktiv perikarditis udløst af cabergolin.

A 72-year-old male with paralysis agitans presented with symptoms and findings of constrictive pericarditis (CP). One year prior, he had a minor lateral MI. The patient had been treated with cabergoline for four years. At pericardiectomy, a thickened pericardium of 1-1,5 cm encased the right side of the heart. The pericardium was normal in the infarction area. Dopamine agonists pergolide and cabergoline for treatment of Parkinson s disease have been associated with development of CP. The absence of pericardial thickening in the infarction area suggests cabergoline as a probable cause.