Electrocardiographic markers of atrial cardiomyopathy predict ineffective cardioversion: a FinCV2 cohort study

Aims Rhythm control using electrical cardioversion (CV) is a common treatment strategy for patients with symptomatic atrial fibrillation (AF). To guide clinical decision making, we sought to assess if electrocardiographic interatrial blocks could predict CV failure or AF recurrence as the phenomenon is strongly associated with atrial arrhythmias. Methods This study included 715 patients who underwent a CV for persistent AF lasting >48 h. P-wave duration and morphology were analyzed in post-procedure or the most recent sinus rhythm electrocardiograms and compared with rates of CV failure and AF recurrence within 30 days after CV as well as their combination (ineffective CV). Results CV was unsuccessful in 63 out of 715 patients (8.8%) and AF recurred in 209 out of 652 (29.2%) patients within 30 days after CV. Overall, 272 (38.0%) CVs turned out ineffective. Advanced interatrial block (AIAB) defined as P-wave duration ≥120 ms and biphasic morphology in inferior leads (II, III and aVF) was diagnosed in 72 (10.1%) cases. AIAB was an independent predictor for CV failure (OR 4.51, 95%CI 1.76–11.56, p = .002), AF recurrence (OR 2.93, 95%CI 1.43–5.99, p = .003) and ineffective CV (OR 3.87, 95%CI 2.04–7.36, p < .001). Conclusion AIAB predicted CV failure, AF recurrence as well as their composite. This study presents an easy electrocardiographic tool for the identification of patients with persistent AF who might not benefit from an elective CV in the future. KEY MESSAGES Interatrial blocks are very common in patients with atrial fibrillation. Advanced interatrial block predicts ineffective cardioversion.

Author's Reply

Interatrial block (IAB) is a strong predictor of recurrence of atrial fibrillation (AF). IAB is a conduction delay through the Bachman region, which is located in the upper region of the interatrial space. During IAB, the impulse travels from the right atrium to the interatrial septum (IAS) and coronary sinus to finally reach the left atrium in a caudocranial direction. No relation between the presence of IAB and IAS thickness has been established yet. To determine whether a correlation exists between the degree of IAB and the thickness of the IAS and to determine whether IAS thickness predicts AF recurrence. Sixty-two patients with diagnosis of paroxysmal AF undergoing catheter ablation were enrolled. IAB was defined as P-wave duration ≥120ms. IAS thickness was measured by cardiac computed tomography. Among 62 patients with paroxysmal AF, 45 patients (72%) were diagnosed with IAB. Advanced IAB was diagnosed in 24 patients (39%). Forty-seven patients were male. During a mean follow-up period of 49.8±22months (range 12-60months), 32 patients (51%) developed AF recurrence. IAS thickness was similar in patients with and without IAB (4.5±2.0mm vs. 4.0±1.4mm; p=.45) and did not predict AF. Left atrial size was significantly enlarged in patients with IAB (40.9±5.7mm vs. 37.2±4.0mm; p=.03). Advanced IAB predicted AF recurrence after the ablation (OR: 3.34, CI: 1.12-9.93; p=.03). IAS thickness was not significantly correlated to IAB and did not predict AF recurrence. IAB as previously demonstrated was an independent predictor of AF recurrence.

Background: This study aimed to investigate whether advanced interatrial block (IAB) is a predictor of recurrent atrial fibrillation (AF) and/or ischemic stroke in elderly patients with AF and hypertension.Methods and objectives: Five hundred and sixteen elderly inpatients (mean age 85.53 ± 9.08 years; 5.43% women) with concurrent paroxysmal AF and hypertension were enrolled in this retrospective observational study. Data on comorbidity, medication, digital electrocardiograms (ECG), and outcomes were obtained from the medical records and follow-up examinations. IAB was classified as partial IAB or advanced IAB according to 12-lead surface ECG analysis on admission. Advanced IAB was defined as a maximum P wave duration of >120 ms with biphasic (±) morphology in leads II, Ⅲ, and aVF by two blinded investigators. The endpoints were recurrent AF and ischemic stroke.Results: We enrolled 120 patients (23.26%) with partial IAB and 187 (36.24%) with advanced IAB. The mean follow-up duration was 19 months. A total of 320 patients (62.02%) developed AF recurrence, and 31 (6.01%) experienced ischemic stroke. Significant predictors of advanced IAB in multivariate analysis were older age (>80 years), increased left atrial diameter (>40 mm), and being overweight (body mass index >25 kg/m2). In the multivariable comprehensive Cox regression analyses, partial IAB was associated with AF recurrence. Advanced IAB was an independent predictor of increased risk of AF recurrence and ischemic stroke.Conclusion: Both partial and advanced IAB are associated with AF recurrence in elderly patients with hypertension. Furthermore, advanced IAB is an independent predictor of ischemic stroke.

Advanced interatrial block predicts clinical recurrence of atrial fibrillation after catheter ablation

Funding Acknowledgements Type of funding sources: None. Introduction There has been an increasing interest in Interatrial block (IAB) in recent years, especially regarding its role in atrial fibrillation (AF). The aim of the present study was to compare the characteristics of inpatients and outpatients who developed new-onset AF versus those who did not. Material and methods This single-centre, prospective observational cohort study on consecutive inpatients and outpatients referred to our institution for routine evaluation. ALl participants (n=8012) aged ≥18 years (mean 69.6±13.3 years, male 51.1%) underwent 12-lead ECG and transthoracic echocardiography. Patients were scheduled for the followup visits and new-onset AF was documented as an outcome. Enrollment lasted from June 2000 to June 2013, with the mean follow up time of 7.3 years. AF was defined as irregular RR intervals without any distinct detectable P-waves for at least 30 seconds. New onset AF is defined as a new onset or a first detectable episode of AF whether symptomatic or not. IAB was diagnosed when P-wave duration was ≥120 ms and positive in inferior leads (partial IAB) or biphasic (advanced IAB). Results The frequency of new-onset AF was 9.8%. IAB was found in 1251 patients (15.6%); advanced and partial IAB were found in 1.3% and 14.3%, respectively. IAB was more common in AF than in the sinus rhythm (33.1%; n=255 vs. 13.8%; n=996) as AF was more common in patients with IAB than without it (20.4%; n=255 vs. 7.8%; n=525). In the multivariate model, both advanced (OR 7.45, 95% CI 4.97-11.17) and partial IAB (OR 2.75 95% CI 2.31-3.37) were associated with increased risk of AF. Conclusion Both partial and advanced IAB are associated with increased risk of AF; however, the risk of AF was lower for partial than advanced IAB.

POSTER PRESENTATIONS

Management of atrial fibrillation (AF) is hampered by frequent recurrences after restoration of sinus rhythm. Delayed interatrial conduction has been associated with the development of AF in different clinical settings. The aim of our study was to assess whether advanced interatrial block (aIAB) was associated with AF recurrence after pharmacological cardioversion with two different antiarrhythmic drugs. We included 61 patients with recent onset AF without structural heart disease that underwent successful pharmacological cardioversion. Thirty-one patients received a single oral dose of propafenone, and 30 patients received iv vernakalant. A 12-lead ECG (filter 150Hz, 25mm/s, 10mm/mV) after conversion was evaluated for the presence of interatrial block (IAB); partial (pIAB): P-wave duration>120ms, and advanced (aIAB): P-wave>120ms and biphasic morphology (±) in inferior leads. Clinical follow-up and electrocardiographic recordings were performed for a 12-month period. Age was 58±10.4years and 50.8% were male. aIAB was present in 11 patients (18%) and pIAB in 10 (16.4%). At 1-year follow-up, 22 patients (36%) had AF recurrence. The recurrence rate with aIAB was 90.9% versus 70% in those with pIAB and 12.5% in normal P-wave duration (P=0.001). The presence of aIAB was strongly associated with AF recurrence (odds ratio 18.4 in multivariable modeling). Recurrence was not affected by the drug used for cardioversion (P=0.92). Advanced interatrial block is associated with higher risk of AF recurrence at 1year after pharmacological cardioversion, independent of the drug used.

Aims: The present study attempted to evaluate the prevalence of basal interatrial blocks (IABs), their associations with clinical parameters, and the interatrial conduction in the follow-up after a successful transcatheter aortic valve implantation (TAVI) procedure among patients with severe aortic stenosis. Methods: We retrospectively evaluated the findings of 90 patients undergoing TAVI in our center. Overall, we considered the presence and grades of IABs and P-wave durations in electrocardiograms (ECG), preoperative echocardiography (ECHO) findings (maximum and mean gradients and left atrium (LA) diameter), valve size and type, and changes in these parameters at sixth month. Results: Forty-six patients were included in the study which are suitable for the pre-determined inclusion criteria. We found the mean age of the patients to be 74.78 ± 8.66 years. In preoperatively-evaluated ECGs, while we detected partial IABs in 37% of the patients, there were advanced IABs in 6.5%, but 56.5% yielded no interatrial conduction disorder. On the other hand, in postoperatively-evaluated ECGs, while we observed partial IABs in 30.4% of the patients, there were advanced IABs among 21.7% (p = 0.017). Nevertheless, we could not conclude any IABs among 47.8% of the patients. Besides, 54.3% of the patients received a self-expandable valve, and a balloon-expandable valve was inserted in 45.7%. In this regard, we detected partial (7 patients) and advanced (2 patients) IABs in the preoperatively-evaluated ECGs of the patients receiving a self-expandable valve. In the postoperative ECGs of these patients, while the partial IAB remained the same in 4 patients (57.1%), it progressed to an advanced IAB in 3 (42.9%). In addition, while the advanced IAB regressed to a partial IAB in one patient, it remained the same for the other patient. In this group, the mean P-wave durations were found to be 118.4±22.67 before the TAVI and 119.6±21.69 after the TAVI (p = 0.113). In the preoperative ECGs of 21 patients with a balloon-expandable valve, we detected partial IABs in 10 patients and an advanced IAB in one patient. While a partial IAB developed in five patients (p = 0.022), five patients with a partial IAB developed an advanced IAB following the procedure (p = 0.022). In this group, we noticed a significant difference between preoperative (127.62±19.4) and postoperative (138.71+ 32.03) P-wave durations (p = 0.038). Conclusion: In a nutshell, we concluded no significant change in interatrial conduction time of the patients with TAVI compared to the baseline in their sixth-month ECGs. When considered by valve type, we concluded that the development and progression of IABs were significant among those with a balloon-expandable valve. The higher postoperative mean gradient among those with a balloon-expandable valve compared to those with a self-expandable valve may be associated with significantly longer P-wave duration among those with a balloon-expandable valve.

Advanced interatrial block (IAB), is an unrecognized surrogate of atrial dysfunction and a trigger of atrial dysrhythmias, mainly atrial fibrillation (AF). Our aim was to prospectively assess whether advanced IAB in sinus rhythm is associated with AF and stroke in elderly outpatients with structural heart disease, a group not previously studied. Prospective observational registry that included outpatients aged ≥70 years with structural heart disease and no previous diagnosis of AF. Patients were divided into three groups: normal P-wave duration (<120 ms), partial IAB (P-wave duration ≥120 ms, positive in the inferior leads), and advanced IAB [P-wave duration ≥120 ms, biphasic (plus/minus) morphology in the inferior leads]. Among 556 individuals, 223 had normal P-wave (40.1%), 196 partial IAB (35.3%), and 137 advanced IAB (24.6%). After a median follow-up of 694 days, 93 patients (16.7%) developed AF, 30 stroke (5.4%), and 34 died (6.1%). Advanced IAB was independently associated with AF -[hazard ratio (HR) 2.9, 95% confidence interval (CI) 1.7-5.1; P < 0.001], stroke [HR 3.8, 95% CI 1.4-10.7; P = 0.010), and AF/stroke (HR 2.6, 95% CI 1.5-4.4; P = 0.001). P-wave duration (ms) was independently associated with AF (HR 1.05, 95% CI 1.03-1.07; P < 0.001), AF/stroke (HR 1.04, 95% CI 1.02-1.06; P < 0.001), and mortality (HR 1.04, 95% CI 1.00-1.08; P = 0.021). The presence of advanced IAB in sinus rhythm is independently associated with AF and stroke in an elderly population with structural heart disease and no previous diagnosis of AF. P-wave duration was also associated with all-cause mortality.

To evaluate the impact of statin therapy on the recurrence rate in patients with persistent atrial fibrillation (AF) after electrical cardioversion. PubMed, EMBbase, Cochrane central register of controlled trials were searched up to February 2015 to identify randomized controlled trials, which reported the effect of statin therapy on AF recurrence after electrical cardioversion. The data were analyzed by RevMan 5.3 and Stata 12.0 software. Six trials with 572 patients were included. The result showed that statin therapy had no effect on the recurrence rate in patients with persistent AF after electrical cardioversion (OR=0.60, 95%CI: 0.32-1.11, P>0.05) compared with controls. Four out of the six trials investigated the effect of atorvastatin on the recurrence rate of AF after electrical cardioversion, subgroup analysis of these trials showed that compared with controls, atorvastatin had no effect on the recurrence of AF after electrical cardioversion (OR=0.59, 95%CI: 0.25-1.39, P>0.05). Three out of the six trials had high quality (Jadad score≥3), subgroup analysis of these trials also showed that statins did not affect the recurrence rate of AF after electrical cardioversion (OR=0.76, 95%CI: 0.49-1.16, P>0.05). This analysis suggested that statin therapy had no effect on the recurrence rate in patients with persistent AF after electrical cardioversion.

Background Advanced interatrial block (IAB), prolonged and bimodal P waves in surface ECG inferior leads, is an unrecognized surrogate of atrial dysfunction and a trigger of atrial dysrhythmias, mainly atrial fibrillation (AF). Our aim was to prospectively assess whether advanced IAB in sinus rhythm precedes AF and stroke in elderly outpatients with structural heart disease, a group not previously studied. Methods Prospective observational registry that included outpatients aged ≥70 years with structural heart disease and no previous diagnosis of AF. Patients were divided into three groups according to P-wave characteristics. Results Among 556 individuals, 223 had normal P-wave (40.1%), 196 partial IAB (35.3%), and 137 advanced IAB (24.6%). After a median follow-up of 694 days; 93 patients (16.7%) developed AF, 30 stroke (5.4%), and 34 died (6.1%). Advanced IAB was independently associated with AF (hazard ratio [HR] 2.9, 95% confidence interval [CI] 1.7–5.1, p&amp;lt;0.001), stroke (HR 3.8, 95% CI 1.4–10.7, p=0.010), and AF/stroke (HR 2.6, 95% CI 1.5–4.4, p=0.001). P-wave duration (ms) was independently associated with AF (HR 1.05, 95% CI 1.03–1.07, p&amp;lt;0.001), AF/stroke (HR 1.04, 95% CI 1.02–1.06, p&amp;lt;0.001), and mortality (HR 1.04, 95% CI 1.00–1.08, p=0.021). Conclusions The presence of advanced IAB in sinus rhythm is a risk factor for AF and stroke in an elderly population with structural heart disease and no previous diagnosis of AF. P-wave duration was also associated with all-cause mortality. Figure. Age- and sex-adjusted linear and non-linear association between P-wave duration (msec) and atrial fibrillation (A), stroke (B), and atrial fibrillation or stroke (C) risk. Results of a generalized additive model with spline smoothing functions and 4 degrees of freedom. Figure 1. Kaplan-Meyer curves of survival free of atrial fibrillation (A), stroke (B) and atrial fibrillation or stroke (C) in patients with normal P-wave, partial interatrial block (IAB) and advanced IAB. Funding Acknowledgement Type of funding source: None

Predictive value of inter-atrial block for new onset or recurrent atrial fibrillation: A systematic review and meta-analysis.

To the Editor:With great interest, we have read the article of Fan and colleagues 1 on the effects of biatrial pacing in the prevention of postoperative atrial fibrillation after coronary artery bypass surgery.By measuring P-wave duration from 12-lead surface ECGs and calculating P-wave dispersion, they found that biatrial pacing resulted in a more significant reduction in P-wave dispersion when compared with single-site atrial pacing.Although these results are interesting, we believe that they should be considered cautiously because of the limited accuracy of electrocardiographic measurements performed manually on paper-printed ECGs obtained at a standard signal size and paper speed.Our research group has introduced P-wave dispersion as a simple electrocardiographic predictor of paroxysmal lone atrial fibrillation. 2Although acceptable intraobserver and interobserver errors in the measurement of P-wave duration in 12-lead ECGs have been reported, 2 well-known difficulties in defining P-wave onset and offset may restrict the accuracy and reproducibility of the measurements.To overcome some of these restrictions, we introduced a more advanced technology-assisted method that enables us to measure P-wave duration from digitally recorded and stored ECG data. 3A computer-based ECG system is used, which records all 12 ECG leads simultaneously at a sampling rate of 1200 Hz and with 12-bit analog-to-digital conversion. 3 A sufficient sampling rate and amplitude resolution are necessary for high-resolution ECG analysis.For each lead, the average complex is calculated, and P-wave duration is measured manually from the average complexes displayed on a high-resolution computer screen. 3 To compare the different methods for manual P-wave duration measurement in 12-lead ECGs, another study was conducted. 4 The conclusion reached was that manual measurement of P-wave duration in standard 12-lead ECGs is feasible and more stable and reliable when performed on the high-resolution screen of a digital ECG system than with more conventional methods involving paper-printed ECGs. 4 Therefore, manual measurement of P-wave duration performed on standard paper-printed ECGs is of limited accuracy.To achieve greater precision in measuring P-wave duration from 12-lead ECGs obtained and stored on paper, we believe that scanning and digitizing ECG signals from paper records using an optical scanner is a feasible and accurate alternative method.

ORAL PRESENTATION