Detection of paroxysmal atrial fibrillation in 994 patients with a cerebrovascular event by intermittent 21-day ECG-monitoring and 7-day continuous Holter-recording.

Background: The detection of paroxysmal atrial fibrillation (AF) is of importance in stroke care. The method used is continuous electrocardiogram (ECG)-monitoring or multiple short ECG-recordings during an extended period. Their relative efficiency is a matter of discussion. In a retrospective cohort study on 994 patients with an ischemic stroke or transient ischemic attack (TIA), we have compared continuous 7-day monitoring to intermittent recording 60 sec three times daily with a handheld device during 3 weeks. We related the result to subsequent occurrence of AF as detected in 12-lead ECG recordings. Methods: The patients were identified in the local database of cardiovascular investigations. Their clinical profile and vital status during the follow-up were obtained from the Swedish Stroke Register and the Swedish general population registry. For comparison, we used an age- and sex-matched population with no known cerebrovascular event and a population with a cerebrovascular event that was not screened. Results: AF was detected in 7.1% by continuous screening and in 5.1% by intermittent screening (P = 0.3). During follow-up of 32 months, AF in 12-lead ECG was found in 7.0%. In the subgroup with positive screening, 46.3% had AF compared with 6.7% in the subgroup with negative screening (P < 0.0001). Conclusions: The two screening approaches had a similar yield of arrhythmia, in spite of the group with intermittent monitoring having a more favorable clinical profile. A positive screening was highly predictive of AF in ECG during the follow-up.

Implantable cardiac devices in adult patients with repaired tetralogy of Fallot.

OBJECTIVES: Implantable cardiac devices are common in patients with tetralogy of Fallot (ToF) (18.3-21.3%) according to previous reports from large centres. We conducted this study to investigate the prevalence and incidence of cardiac devices in a less selected population of patients with ToF and assess factors other than arrhythmia associated with having a device. Design: 530 adult (≥18 years) patients with repaired ToF were identified in the national registry of congenital heart disease (SWEDCON) and matched with data from the Swedish pacemaker registry. Patients with implantable cardiac devices were compared with patients without devices. Results: Seventy-five patients (14.2%) had a device; 51 (9.6%) had a pacemaker and 24 (4.5%) had an implantable cardioverter defibrillator. The incidence in adult age (≥18 years) was 5.9/1000 patient years. Estimated device free survival was 97.5% at twenty, 87.2% at forty and 63.5% at sixty years of age. Compared with previous studies, the prevalence of devices was lower, especially for ICD. In multivariate logistic regression, cardiovascular medication (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.8-6.8), impaired left ventricular function, (OR 2.6, 95%CI 1.3-5.0) and age (OR 1.02, 95%CI 1.002-1.05) were associated with having a device. Conclusion: The prevalence of devices in our population, representing a multicenter register cohort, was lower than previously reported, especially regarding ICD. This can be due to differences in treatment traditions with regard to ICD in this population, but it may also be that previous studies have reported selected patients with more severe disease.

Increased risk of late pacemaker implantation after ablation for atrioventricular nodal reentry tachycardia: A 10-year follow-up of a nationwide cohort.

BACKGROUND: Catheter ablation of the slow pathway is the standard treatment of atrioventricular nodal reentry tachycardia (AVNRT) with a well described low risk of periprocedural atrioventricular block. Less is known about the risk of pacemaker implantation late after ablation. OBJECTIVE: We aimed to quantify the risk of late pacemaker implantation in a countrywide cohort undergoing first-time ablation for AVNRT. METHODS: All patients undergoing first-time ablation for AVNRT in Sweden from 2004 to 2014 were identified from the Swedish catheter ablation registry and matched against the Swedish Pacemaker and ICD registry. The cohort was compared to patients ablated for an accessory pathway (AP) and to matched controls. RESULTS: During follow-up of 2039 days, pacemaker was implanted later than 30 days after ablation in 96 of 6842 patients with AVNRT (1.4%), 29 of 4065 patients with AP (0.7%) (P = .001), and 124 of 33,270 controls (0.4%) (P < .00001). A periprocedural pacemaker (≤30 days postablation) was implanted in 32 of 6877 patients with AVNRT (0.5%) and 9 of 4079 patients with AP (0.2%) (P = .05). With cryoablation, 5 patients needed periprocedural pacemaker implantation. Pacemakers were implanted before ablation in 88 of 6977 patients with AVNRT (1.3%) and 11 of 4100 patients with AP (0.3%); the prevalence of pacemaker implants in controls was 124 of 33,270 (0.4%) (P < .00001 for both comparisons). CONCLUSION: The risk of late pacemaker implantation after AVNRT ablation was low but 3 times higher than that in the control population and 3 times higher than the risk of periprocedural pacemaker implantation. Similar results were observed with cryoablation and radiofrequency ablation. Ablation may not be the cause of increased late pacemaker implantation risk.

A decade of catheter ablation of cardiac arrhythmias in Sweden: ablation practices and outcomes.

AIMS: Catheter ablation is considered the treatment of choice for many tachyarrhythmias, but convincing 'real-world' data on efficacy and safety are lacking. Using Swedish national registry data, the ablation spectrum, procedural characteristics, as well as ablation efficacy and reported adverse events are reported. METHODS AND RESULTS: Consecutive patients (≥18 years of age) undergoing catheter ablation in Sweden between 01 January 2006 and 31 December 2015 were included in the study. Follow-up (repeat ablation and vital status) was collected through 31 December 2016. A total of 26 642 patients (57 ± 15 years, 62% men), undergoing a total of 34 428 ablation procedures were included in the study. In total, 4034 accessory pathway/Wolff-Parkinson-White syndrome (12%), 7358 AV-nodal re-entrant tachycardia (21%), 1813 atrial tachycardia (5.2%), 5481 typical atrial flutter (16%), 11 916 atrial fibrillation (AF, 35%), 2415 AV-nodal (7.0%), 581 premature ventricular contraction (PVC, 1.7%), and 964 ventricular tachycardia (VT) ablations (2.8%) were performed. Median follow-up time was 4.7 years (interquartile range 2.7-7.0). The spectrum of treated arrhythmias changed over time, with a gradual increase in AF, VT, and PVC ablation (P < 0.001). Decreasing procedural times and utilization of fluoroscopy with time, were seen for all arrhythmia types. The rates of repeat ablation differed between ablation types, with the highest repeat ablation seen in AF (41% within 3 years). The rate of reported adverse events was low (n = 595, 1.7%). Death in the immediate period following ablation was rare (n = 116, 0.34%). CONCLUSION: Catheter ablations have shifted towards more complex procedures over the past decade. Fluoroscopy time has markedly decreased and the efficacy of catheter ablation seems to improve for AF.

Cardioversion of atrial fibrillation does not affect obstructive sleep apnea.

BACKGROUND: Sleep apnea is common in patients with atrial fibrillation, but the effect of the cardioversion of atrial fibrillation to sinus rhythm on central and obstructive apneas is mainly unknown. The primary aim of the study was to analyze the association between cardioversion of atrial fibrillation and sleep apneas, to investigate whether obstructive or central sleep apneas are reduced following cardioversion. A secondary objective was to study the effect on sleep quality. METHODS: Twenty-three patients with atrial fibrillation were investigated using overnight polysomnography, including esophagus pressure monitoring and ECG, before and after the cardioversion of persistent atrial fibrillation. RESULTS: Obstructive sleep apnea occurred in 17/23 patients (74%), and central sleep apnea in 6/23 patients (26%). Five patients had both obstructive and central sleep apnea. Sinus rhythm at follow-up was achieved in 16 patients. The obstructive apnea-hypopnea index, central apnea-hypopnea index, and the number of patients with obstructive or central sleep apnea did not differ before and after restoration of sinus rhythm. Sleep time, sleep efficiency, time in different sleep stages, and subjective daytime sleepiness were normal and unaffected by cardioversion. CONCLUSIONS: Both obstructive and central sleep apneas are highly prevalent in patients with persistent atrial fibrillation. Obstructive sleep apneas are unaffected by the cardioversion of atrial fibrillation to sinus rhythm. The sleep pattern is normal and unaffected by cardioversion in patients with atrial fibrillation. CLINICAL TRIAL REGISTRATION: Trial number NCT00429884.

Assessment of Use vs Discontinuation of Oral Anticoagulation After Pulmonary Vein Isolation in Patients With Atrial Fibrillation.

Importance: Pulmonary vein isolation (PVI) is a recommended treatment for patients with atrial fibrillation, but it is unclear whether it results in a lower risk of stroke. Objectives: To investigate the proportion of patients discontinuing anticoagulation treatment after PVI in association with the CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, stroke [doubled], vascular disease, age 65-74 years, sex category [female]) score, identify factors predicting stroke after PVI, and explore the risk of cardiovascular events after PVI in patients with and without guideline-recommended anticoagulation treatment. Design, Setting, and Participants: A retrospective cohort study was conducted using Swedish national health registries from January 1, 2006, to December 31, 2012, with a mean-follow up of 2.6 years. A total of 1585 patients with atrial fibrillation undergoing PVI from the Swedish Catheter Ablation Register were included, with information about exposure to warfarin in the national quality register Auricula. Data analysis was performed from January 1, 2015, to April 30, 2016. Exposures: Warfarin treatment. Main Outcomes and Measures: Ischemic stroke, intracranial hemorrhage, and death. Results: In this cohort of 1585 patients, 73.0% were male, the mean (SD) age was 59.0 (9.4) years, and the mean (SD) CHA2DS2-VASc score was 1.5 (1.4). Of the 1585 patients, 1175 were followed up for more than 1 year after PVI. Of these, 360 (30.6%) discontinued warfarin treatment during the first year. In patients with a CHA2DS2-VASc score of 2 or more, patients discontinuing warfarin treatment had a higher rate of ischemic stroke (5 events in 312 years at risk [1.6% per year]) compared with those continuing warfarin treatment (4 events in 1192 years at risk [0.3% per year]) (P = .046). Patients with a CHA2DS2-VASc score of 2 or more or those who had previously experienced an ischemic stroke displayed a higher risk of stroke if warfarin treatment was discontinued (hazard ratio, 4.6; 95% CI, 1.2-17.2; P = .02 and hazard ratio, 13.7; 95% CI, 2.0-91.9; P = .007, respectively). Conclusions and Relevance: These findings indicate that discontinuation of warfarin treatment after PVI is not safe in high-risk patients, especially those who have previously experienced an ischemic stroke.

Two Cases of LQT Syndrome with Malignant Syncope after Switch from Propranolol to Bisoprolol.

Propranolol in slow-release form has been the first-line treatment in long QT (LQT) until it was withdrawn from the market. We describe two cases where a switch to bisoprolol resulted in worsening of arrhythmia control: A man with LQT2, asymptomatic on propranolol, experienced syncope after switching to bisoprolol 5 mg daily. He switched back to propranolol and has remained asymptomatic during subsequent 12 months. A man with classical Jervell Lange-Nielsen syndrome, previous gangliectomy, and ICD implantation, switched to bisoprolol 5 mg daily. Four months later he experienced a tachycardia storm. He switched back to propranolol and has remained free from arrhythmias during subsequent 12 months.

The effect of concomitant cardiac resynchronization therapy on quality of life in patients with heart failure undergoing cardiac surgery.

OBJECTIVES: To evaluate the effect of concomitant cardiac resynchronization therapy (CRT) on health related quality of life (QoL) in patients with heart failure (HF) and ventricular dyssynchrony undergoing cardiac surgery. METHODS: Twenty-eight patients received permanent epicardial CRT in connection to coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR) (CRT group). Thirty-seven HF patients without concomitant CRT served as a comparison group (non-CRT group). SF-36 was used to assess QoL in the two groups and was also compared with the general Swedish population. RESULTS: The median follow-up time was 28 months after surgery (range 8 to 44 months). No difference in QoL could be shown between the CRT group and the comparison group. Several subscales of QoL in the CRT group were in range with the general Swedish population. CONCLUSION: Concomitant CRT for patients with HF and ventricular dyssynchrony undergoing CABG and/or AVR did not result in a higher estimated QoL compared to HF patients without CRT.

U22 protocol as measure of symptomatic improvement after catheter ablation of atrial fibrillation.

INTRODUCTION: Left atrial catheter ablation is useful as symptomatic treatment in selected patients with atrial fibrillation (AF). Evaluation requires measurement of arrhythmia-related symptoms. Many of the published protocols have drawbacks and have been used in AF only, with no possible comparison to other ablations that compete for the same resources. U22 is a published protocol that quantifies paroxysmal tachycardia symptoms through scales with 11 answer alternatives, translated into discrete numerical scales 0-10. It has been shown to reflect the clinical improvement after ablation of supraventricular tachycardia. Here we report the use of U22 in measuring improvement after catheter ablation for AF. MATERIAL AND METHODS: A total of 105 patients underwent first-time ablation for AF and answered U22 and SF-36 forms at baseline and follow-up 304 (SD 121) days after ablation. Independently, the patients underwent a clinical follow-up. All decisions regarding medication and reablation were taken without knowledge of the symptom scores. Results. The U22 scores for well-being, arrhythmia as cause for impaired well-being, derived time-aspect score for arrhythmia, and discomfort during attack detected relevant improvements of symptoms after the ablation. U22 showed larger improvement in patients undergoing only one procedure than in patients who later underwent repeated interventions, thus reflecting the independent clinical decision for reablation. CONCLUSION: U22 quantifies the symptomatic improvement after AF ablation with adequate internal consistency and construct validity. U22 mirrors aspects of the arrhythmia symptomatology other than SF-36.

Right ventricular lead positioning does not influence the benefits of cardiac resynchronization therapy in patients with heart failure and atrial fibrillation.

AIMS: Little is known about the optimal right ventricular (RV) pacing site in cardiac resynchronization therapy (CRT). This study compares bi-ventricular pacing at the left ventricular (LV) free wall combined with two different RV stimulation sites: RV outflow tract (RVOT+LV) vs. RV-apex (RVA+LV). METHODS AND RESULTS: Thirty-three patients (32 males) with chronic heart failure, NYHA class III-IV, optimal drug therapy, QRS-duration ≥150 ms, and chronic atrial fibrillation (AF) received CRT with two different RV leads, in the apex (RVA) or outflow tract (RVOT), together with an LV lead, all connected to a bi-ventricular pacemaker. Randomization to pacing in RVOT+LV or RVA+LV was made 1 month after implantation and cross-over to the alternate pacing configuration occurred after 3 months. The median age of patients was 69 ± 10 years, the mean QRS was 179 ± 23 ms, and 58% of patients had ischaemic heart disease. Seven patients had pacemaker rhythm at inclusion and 60% were treated with atrioventricular-junctional ablation before randomization. In the RVA+LV and RVOT+LV pacing modes, 67 and 63% (nonsignificant) responded symptomatically with a decrease of at least 10 points in the Minnesota Living with Heart Failure score. The secondary end-points (6-min walk test, peak oxygen uptake, N-Terminal fragment of B-type Natriuretic Peptide, and left ventricular ejection fraction) showed significant improvement between baseline and CRT, but not between RVOT+LV and RVA+LV. CONCLUSION: In this randomized controlled study, the exact RV pacing site, either apex or outflow tract, did not influence the benefits of CRT in a group of patients with chronic heart failure and AF. ClinicalTrials.gov ID: NCT00457834.

Symptomatic improvement after catheter ablation of supraventricular tachycardia measured by the arrhythmia-specific questionnaire U22.

INTRODUCTION: The main indication for ablation of supraventricular tachycardia is symptomatic relief. Generic measures of quality of life are not suitable for direct evaluation of arrhythmia-related symptoms, and a specific tool is needed. The questionnaire U22 quantifies symptoms associated with arrhythmic events. It uses discrete 0-10 scales for quantification of influence of arrhythmia on well-being, intensity of discomfort, type of dominant symptom, and a time aspect that summarizes duration and frequency of spells. We evaluated U22 in a well defined group of patients with paroxysmal supraventricular tachycardia, undergoing an intervention with a distinct end-point and a high success rate. METHODS: Symptoms in patients with accessory pathway and atrioventricular nodal re-entrant tachycardia scheduled for ablation were measured with U22 and SF-36 on admission. The evaluation was repeated after 6 months. RESULTS: Altogether 58 patients successfully ablated in 2006-2008 completed the four forms (U22 and SF-36 at base-line and follow-up, 210 ± 35 days after ablation). The score for well-being (0-10; 10 being best) increased from 5.9 ± 2.6 to 7.9 ± 1.9 (P < 0.0005). The score for arrhythmia as cause for impairment in well-being (0-10; 10 being highest) decreased from 7.5 ± 2.8 to 2.0 ± 3.1 (P < 0.0005). The time aspect score (0-10) decreased from 4.7 ± 1.5 to 1.4 ± 1.8 (P < 0.0005). The two SF-36 summary measures PCS and MCS increased from 46.9 ± 9.4 to 48.4 ± 10.7 and from 44.9 ± 12.5 to 49.1 ± 9.9 (P = 0.04 and 0.002). CONCLUSION: After successful ablation of accessory pathway and atrioventricular nodal re-entrant tachycardia, the U22 protocol detected a relevant increase in arrhythmia-related well-being. Modest improvement in general well-being was detected by the SF-36 protocol.

Two automatic QT algorithms compared with manual measurement in identification of long QT syndrome.

BACKGROUND: Long QT syndrome (LQTS) is an inherited disorder that increases the risk of syncope and malignant ventricular arrhythmias, which may result in sudden death. METHODS: We compared manual measurement by 4 observers (QT(manual)) and 3 computerized measurements for QT interval accuracy in the diagnosis of LQTS: 1. QT measured from the vector magnitude calculated from the 3 averaged orthogonal leads X, Y, and Z (QTVCG) and classified using the same predefined QTc cut-points for classification of QT prolongation as in manual measurements; 2. QT measured by a 12-lead electrocardiogram (ECG) program (QTECG) and subsequently classified using the same cut-points as in (1) above; 3. The same QT value as in (2) above, automatically classified by a 12-lead ECG program with thresholds for QT prolongation adjusted for age and sex (QTinterpret). The population consisted of 94 genetically confirmed carriers of KCNQ1 (LQT1) and KCNH2 (LQT2) mutations and a combined control group of 28 genetically confirmed noncarriers and 66 unrelated healthy volunteers. RESULTS: QT(VCG) provided the best combination of sensitivity (89%) and specificity (90%) in diagnosing LQTS, with 0.948 as the area under the receiver operating characteristic curve. The evaluation of QT measurement by the 4 observers revealed a high interreader variability, and only 1 of 4 observers showed acceptable level of agreement in LQTS mutation carrier identification (kappa coefficient >0.75). CONCLUSION: Automatic QT measurement by the Mida1000/CoroNet system (Ortivus AB, Danderyd, Sweden) is an accurate, efficient, and easily applied method for initial screening for LQTS.

Heart rate variability during sleep and sleep apnoea in a population based study of 387 women.

Increased sympathetic activity during sleep has been suggested as a link between obstructive sleep apnoea syndrome and cardiovascular disease. Heart rate variability (HRV) is a measure of autonomic effect on the heart. Different parameters have been associated with sympathetic and parasympathetic activity. We have studied HRV in different sleep stages and related the HRV-pattern to sleep apnoea in a population-based sample of 387 women. We investigated the HRV-parameters standard deviation of all R-R intervals (SDNN), root of the averaged square of successive differences (RMSSD), low frequency component (LF), high frequency component (HF), ratio of low frequency component to high frequency component LF/HF and VSAI [variation in sympathetic activity between rapid eye movement (REM) and slow wave sleep, defined as LF(REM)-LF(SWS)]. The HRV-parameters were compared with the results of a full-night polysomnography. Hourly incidence of obstructive episodes was used for classifying the subjects into four apnoea-hypopnoea index (AHI)-groups (<5, > or =5 and <15, 15-30 and >30 events). Individual sleep stages were analysed by pooling all recordings. Women with high AHI had higher heart rate and LF/HF ratio. In subjects with AHI >30, LF/HF ratio however dropped to same level as with AHI <5. Subjects with high AHI had low VSAI. Levels of SDNN, LF and LF/HF ratio during REM and light sleep were similar to wakefulness. In slow wave sleep the parameters decreased. In conclusion, moderately increased prevalence of obstructive apnoeas was associated with signs of higher sympathetic activity. High AHI was however associated with a HRV-pattern suggestive of depressed sympathetic drive and lowered ability to increase it during REM.