Diagnostic reliability of monitoring for premature atrial and ventricular complexes.

AIMS: Short-term ambulatory electrocardiogram (ECG) monitoring is often used to assess premature atrial complex (PAC) and premature ventricular complex (PVC) frequency, but the diagnostic reliability is unknown. The objective of this study was to study the day-to-day variability of PAC and PVC frequency. METHODS AND RESULTS: We used 14-day full-disclosure mobile cardiac telemetry recordings without atrial fibrillation in 8245 US patients aged 17-103 years to calculate the diagnostic reliability of shorter ambulatory ECG recordings compared with 14-day averages. Over 14 days, 1853 patients had ≥500 PACs/day, 410 patients had ≥5000 PACs/day, and 197 patients had ≥10 000 PACs/day; 1640 patients had ≥500 PVCs/day, 354 patients had ≥5000 PVCs/day, and 175 patients had ≥10 000 PVCs/day. After 3 days, the estimated daily PAC frequency differed by ≥50% from the 14-day mean in 25% of patients; for PVCs, the corresponding duration was 7 days. Ten days of monitoring were needed to estimate PAC and PVC frequency within ±20% of the overall 14-day frequency in 80% of patients. For daily PAC and PVC frequencies ≥10 000, single-day estimation had a specificity of 99.3% [95% confidence interval (CI) 99.1-99.5] at a sensitivity of 76.6 (95% CI 70.1-80.4%) for PACs and a 99.6% (95% CI 99.4-99.7%) specificity at 79.4 (95% CI 72.7-85.2) sensitivity for PVCs. After 7 days, the sensitivity increased to 88.8% (95% CI 83.6-92.9) for PACs and 86.9% (95% CI 80.9-91.5%) for PVCs. CONCLUSION: While there is substantial daily variability across most PAC and PVC levels, findings of ≥10 000 PACs or PVCs are highly specific and do not need to be confirmed with longer recordings.

Vernakalant for Rapid Cardioversion of Recent-Onset Atrial Fibrillation: Results from the SPECTRUM Study.

AIMS: Rapid restoration of sinus rhythm using pharmacological cardioversion is commonly indicated in patients with symptomatic recent-onset atrial fibrillation (AF). The objectives of this large, international, multicenter observational study were to determine the safety and effectiveness of intravenous (IV) vernakalant for conversion of AF to sinus rhythm in daily practice. METHODS AND RESULTS: Consenting patients with symptomatic recent-onset AF (< 7 days) treated with IV vernakalant were enrolled and followed up to 24 h after the last infusion or until discharge, in order to determine the incidence of predefined serious adverse events (SAEs) and other observed SAEs and evaluate the conversion rate within the first 90 min. Overall, 2009 treatment episodes in 1778 patients were analyzed. The age of patients was 62.3 ± 13.0 years (mean ± standard deviation). Median AF duration before treatment was 11.1 h (IQR 5.4-27.0 h). A total of 28 SAEs occurred in 26 patients including 19 predefined SAEs, i.e., sinus arrest (n = 4, 0.2%), significant bradycardia (n = 11, 0.5%), significant hypotension (n = 2, 0.1%), and atrial flutter with 1:1 conduction (n = 2, 0.1%). There were no cases of sustained ventricular arrhythmias or deaths. All patients who experienced SAEs recovered fully (n = 25) or with sequelae (n = 1). Conversion rate to sinus rhythm was 70.2%, within a median of 12 min (IQR 8.0-28.0 min). CONCLUSIONS: This large multicenter, international observational study confirms the good safety profile and the high effectiveness of vernakalant for the rapid cardioversion of recent-onset AF in daily hospital practice.

ST segment depression on 24-hour electrocardiography predicts incident atrial fibrillation in two population-based cohorts.

Aims: ST-depression at 24hECG has not been studied in relation to atrial fibrillation (AF) risk. We aimed to determine whether ST-depression at 24hECG was associated with incident AF in two Swedish population-based cohorts - a sub-cohort of the Malmö Diet and Cancer study (MDCS), and the cohort 'Men born in 1914', and to determine whether 24hECG could be used to predict AF development. Methods and results: There were 378 acceptable 24hECG recordings in the MDCS (mean age 64.5 years, 43% men) and 394 acceptable recordings in 'Men born in 1914' (mean age 68.8 years). Incidence of AF was monitored using national registers of hospitalizations and outpatient visits in Sweden. Mean follow-up ± SD (cumulative incidence) was 10.4 ± 2 years (11.3%) in MDCS, and 10.9 ± 4 years (7.3%) in 'Men born in 1914'. ST-depressions were independently associated with incident AF; hazard ratio (HR) (95% CI) 2.41 (1.29-4.50, P = 0.006) and 2.28 (1.05-4.95, P = 0.038) after adjustment [age, sex, height, weight, systolic blood pressure, smoking, anti-hypertensive drugs, LDL/total cholesterol, and HOMA-IR (in MDCS)]. AF incidence was substantially lower in individuals who had neither ST-depressions or high supraventricular activity (SVA, negative predictive value 0.97 and 0.94, in MDCS and 'Men born in 1914', respectively), and similar in men and women. Conclusion: ST-depression at 24h-ECG is independently associated with incident AF, and incidence is substantially lower in individuals with neither ST-depression or high SVA. 24hECG can be used not only to diagnose AF but also to identify individuals at high and low AF risk.

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.

Predictors of successful cardioversion with vernakalant in patients with recent-onset atrial fibrillation.

BACKGROUND: Vernakalant is a novel atrial-selective antiarrhythmic drug able to convert recent-onset atrial fibrillation (AF) with reportedly low proarrhythmic risk. Successful cardioversion predictors are largely unknown. We sought to evaluate clinical and electrocardiographic predictors of cardioversion of recent-onset AF with vernakalant. METHODS: Consecutive patients with AF ≤48 hours admitted for cardioversion with vernakalant (n = 113, median age 62 years, 69 male) were included. Sinus rhythm (SR) within 90 minutes after infusion start was considered to be successful cardioversion. Predictive values of demographics, concomitant therapy, comorbidities, and electrocardiographic parameters were assessed. Atrial fibrillatory rate (AFR), exponential decay, and mean fibrillatory wave amplitude were measured from surface ECG using QRST cancellation and time-frequency analysis. RESULTS: Cardioversion was achieved in 66% of patients. Conversion rate was higher in women than in men (80% vs 58%, P = 0.02) while none of other clinical characteristics, including index AF episode duration, could predict SR restoration. Female gender was predictive of vernakalant's effect in logistic regression analysis (OR = 2.82 95%CI 1.18-6.76, P = 0.020). There was no difference in AFR (350 ± 60 vs 348 ± 62 fibrillations per minute [fpm], P = 0.893), mean fibrillatory wave amplitude (86 ± 33 vs 88 ± 67 µV, P = 0.852), or exponential decay (1.30 ± 0.42 vs 1.35 ± 0.42, P = 0.376) between responders and nonresponders. CONCLUSIONS: Female gender is associated with a higher rate of SR restoration using intravenous (i.v.) vernakalant for recent-onset AF. ECG-derived indices of AF organization, which previous studies associated with effect of rhythm control interventions, did not predict vernakalant's effect.

Reduced forced expiratory volume is associated with increased incidence of atrial fibrillation: the Malmo Preventive Project.

AIMS: Reduced forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) have been associated with increased incidence of cardiovascular diseases. However, whether reduced lung function is also a risk factor for incidence of atrial fibrillation (AF) is still unclear. We aimed to determine whether lung function predicted AF in the Malmö Preventive Project, a large population-based cohort with a long follow-up. METHODS AND RESULTS: The study population consisted of 7674 women and 21 070 men, mean age 44.6 years. The cohort was followed on average for 24.8 years, during which time 2669 patients were hospitalized due to AF. The incidence of AF in relationship to quartiles of FEV1 and FVC and per litre decrease at baseline was determined using a Cox proportional hazards model adjusted for age, height, weight, current smoking status, systolic blood pressure, erythrocyte sedimentation rate, and fasting blood glucose. Forced expiratory volume in one second was inversely related to incidence of AF (per litre reduction in FEV1) hazard ratio (HR): 1.39 [95% confidence interval (CI): 1.16-1.68; P = 0.001] for women, and HR: 1.20 (95% CI: 1.13-1.29; P < 0.0001) for men. Forced vital capacity was also inversely related to incidence of AF (per litre reduction in FVC) HR: 1.20 (95% CI: 1.03-1.41; P = 0.020) for women, and HR: 1.08 (95% CI: 1.02-1.14; P = 0.01) for men. This relationship was consistent in non-smokers as well as smokers, and among individuals younger than the median age of 45.8 years or normotensive subjects. CONCLUSION: Impaired lung function is an independent predictor of AF. This may explain some risk of AF that is currently unaccounted for.

Low fasting plasma insulin is associated atrial fibrillation in men from a cohort study--the Malmö preventive project.

BACKGROUND: Type 2 diabetes has been associated with increased incidence of atrial fibrillation (AF) and cardiovascular disease. Controversy remains regarding the role of insulin in the epidemiology of AF risk. The aim of the present study was to study the association between fasting plasma insulin (FPI) and incidence of AF, as well as any effect modification by fasting blood glucose (FBG) or 2 h post-load blood glucose and body mass index (BMI). METHODS: The study population consisted of 6052 men and 1014 women followed for an average of 26.2 years. There were 983 cases of incident AF. Analysis was performed using Cox regression and competing risks regression approaches. The population was analysed as a whole, and by subgroups according to glucose levels and BMI. RESULTS: After adjustment for age, height, weight, systolic blood pressure and smoking there was a significant inverse association between FPI and AF (hazard ratio; HR) for 4th vs. 1st quartile: 0.69 (95% confidence interval (CI): 0.57-0.83, p < 0.0001) in the cohort as a whole. Among men the corresponding values were HR 0.64 (95% CI 0.52-0.78, p < 0.001) and among women HR 1.16 (95% CI 0.69-1.93, p = 0.58); p-value for interaction 0.06. The protective effects of insulin tended to be weaker in subjects with elevated fasting glucose, implying that the relation between FPI and incident AF could be dependent on the status of individual's glucose metabolism. CONCLUSIONS: High levels of FPI are associated with lower risk of incident AF in a middle-aged population with a long follow-up.

Data standards for atrial fibrillation/flutter and catheter ablation: the European Unified Registries for Heart Care Evaluation and Randomized Trials (EuroHeart).

AIMS: Standardized data definitions are essential for monitoring and assessment of care and outcomes in observational studies and randomized controlled trials (RCTs). The European Unified Registries for Heart Care Evaluation and Randomized Trials (EuroHeart) project of the European Society of Cardiology aimed to develop contemporary data standards for atrial fibrillation/flutter (AF/AFL) and catheter ablation. METHODS AND RESULTS: We used the EuroHeart methodology for the development of data standards and formed a Working Group comprising 23 experts in AF/AFL and catheter ablation registries, as well as representatives from the European Heart Rhythm Association and EuroHeart. We conducted a systematic literature review of AF/AFL and catheter ablation registries and data standard documents to generate candidate variables. We used a modified Delphi method to reach a consensus on a final variable set. For each variable, the Working Group developed permissible values and definitions, and agreed as to whether the variable was mandatory (Level 1) or additional (Level 2). In total, 70 Level 1 and 92 Level 2 variables were selected and reviewed by a wider Reference Group of 42 experts from 24 countries. The Level 1 variables were implemented into the EuroHeart IT platform as the basis for continuous registration of individual patient data. CONCLUSION: By means of a structured process and working with international stakeholders, harmonized data standards for AF/AFL and catheter ablation for AF/AFL were developed. In the context of the EuroHeart project, this will facilitate country-level quality of care improvement, international observational research, registry-based RCTs, and post-marketing surveillance of devices and pharmacotherapies.

Aortic stenosis and mitral regurgitation as predictors of atrial fibrillation during 11 years of follow-up.

BACKGROUND: There is limited information about any association between the onset of atrial fibrillation (AF) and the presence of valvular disease. METHODS: We retrospectively examined 940 patients in sinus rhythm, examined by echocardiography in 1996. During 11 years of follow-up, we assessed the incidence of AF and outcome defined as valvular surgery or death, in relation to baseline valvular function. AS (aortic stenosis) severity at baseline examination was assessed using peak transaortic valve pressure gradient. RESULTS: In univariate analysis, the risk of developing AF was related to AS (significant AS versus no significant AS; hazard ratio (HR) 3.73, 95% confidence interval (CI) 2.39-5.61, p<0.0001) and mitral regurgitation (MR) (significant MR versus no significant MR; HR 2.52, 95% CI 1.77-3.51, p<0.0001). Also the risk of valvular surgery or death was related to AS (HR 3.90, 95% CI 3.09-4.88, p<0.0001) and MR (HR 2.07, 95% CI 1.67-2.53, p<0.0001). In multivariate analyses, adjusting for sex, age, other valvular abnormalities, left ventricular ejection fraction and left atrial size - AS was independently related to both endpoints, whereas MR was not independently related to either endpoint. CONCLUSIONS: AS, but not MR, was independently predictive of development of AF and combined valvular surgery or death. In patients with combined AS and MR, the grade of AS, more than the grade of MR, determined the risk of AF and combination of valvular surgery or death. Further studies using contemporary echocardiographic quantification of aortic stenosis are warranted to confirm these retrospective data based on peak transaortic valve pressure gradient.

Elevated premature ventricular complex counts on 24-hour electrocardiogram predict incident atrial fibrillation and heart failure-A prospective population-based cohort study.

Background: Premature ventricular complexes (PVCs) are known to predict heart failure (HF) and premature atrial contractions (PACs) are known to predict atrial fibrillation (AF) and stroke. PVCs and PACs share pathophysiological mechanisms; however, the combined effects of PVCs and PACs on HF, AF, and stroke risk have not been studied. Objectives: To study elevated PVC counts on 24-hour electrocardiogram monitoring (24hECG) in relation to incidence of AF, HF, and stroke, and whether this effect is altered by PAC frequency. Methods: The prospective population-based Malmö Diet and Cancer study includes 24hECG registrations in 375 AF- and HF-free subjects (mean age 65 years, 55% women). During 17 years of follow-up there were 28 HF, 89 AF, and 28 stroke events. The hazard ratios (HR) of elevated PVC counts (defined as the top quartile, ≥77/24 hours) vs lower quartiles were assessed using multivariable adjusted Cox regression models. Results: Elevated PVC counts predicted incident AF (HR 1.9, 95% confidence interval [CI] 1.2-3.0) and HF (HR 3.1, 95% CI 1.4-7.0). Results were similar after adjustment for NT-proBNP and PACs. Multiform PVCs were associated with even higher risks (HR 2.8, 95% CI: 1.7-4.6 for AF; HR 5.0, 95% CI 2.2-11.7 for HF), as was the presence of both elevated PACs and PVCs (9% of the population, HR 4.1, 95% CI 2.4-6.8 for AF and HR 4.3, 95% CI 1.7-11.4 for HF). No significant association was found between elevated PVC counts and incident stroke. Conclusion: Elevated PVC counts predict incident AF and HF, particularly if PVCs are multiform or occur in combination with elevated PAC counts.