Prior History Of Atrial Fibrillation Research Articles

Factors associated with early atrial fibrillation after ablation of common atrial flutter. A single centre prospective study.

The occurrence of early atrial fibrillation (< or = 6 months) after ablation of common atrial flutter is of clinical significance. Variables predicting this evolution in ablated patients without a previous atrial fibrillation history have not been fully investigated. The aim of the present study was: (1) to identify predictive factors of early atrial fibrillation (< or = 6 months) in the overall population following atrial flutter catheter ablation; (2) to identify predictive variables of early atrial fibrillation following (< or = 6 months) atrial flutter catheter ablation within a subgroup of patients without documented prior atrial fibrillation. This study prospectively included 96 consecutive patients (age 65 +/- 13 years; 18 women) over a 12-month period. Their counterclockwise flutter was ablated by radiofrequency, by the same operator, with an 8-mm-tip catheter. Clinical, electrophysiological and echocardiographic data were collected and 27 variables were retained for analysis: age; gender; type of atrial flutter (permanent vs paroxysmal); symptom duration (months +/- SD); pre-ablation history of atrial fibrillation; structural heart disease; left ventricular ejection fraction (%); left atrial size (mm); cava--tricuspid isthmus dimension; septal isthmus dimension; systolic pulmonary pressure > or < or = 30 mmHg; right atrial area; left atrial area; isthmus block; number of radiofrequency applications (+/- SD); antiarrhythmic drugs at discharge; left ventricular diastolic diameter; left ventricular systolic diameter; left ventricular telediastolic volume; left ventricular telesystolic volume; A-wave velocity (cm . s(-1)); E-wave velocity (cm . s(-1)); E/A; isovolumetric relaxation time; E-wave deceleration time; significant mitral regurgitation and flutter cycle length (ms). Of the 96 consecutive ablated patients, early atrial fibrillation was documented in 16 patients (17%). Atrial fibrillation occurred 30 +/- 46 days (range 1 to 171 days) after ablation. Univariate analysis associated an early occurrence of atrial fibrillation with: atrial fibrillation history, left ventricular ejection fraction, left atrial size, left ventricular telesystolic volume, A-wave velocity, significant mitral regurgitation and flutter cycle length. Multivariate analysis using a Cox model found that the only independent predictors of early atrial fibrillation were left ventricular ejection fraction and pre-ablation history of atrial fibrillation. In the subgroup without prior atrial fibrillation history (n=63; 66%), the only independent predictor of early atrial fibrillation was the presence of a significant mitral regurgitation. In a subgroup of patients without atrial fibrillation history, 8% of patients revealed an early atrial fibrillation. Mitral regurgitation is a strong predictive factor of early atrial fibrillation occurrence with 80% sensitivity, 78% specificity and 98% negative predictive value. These data should be considered in post-ablation management.

Recurrent atrial flutter and atrial fibrillation after catheter ablation of the cavotricuspid isthmus: a very long-term follow-up of 333 patients.

Radiofrequency catheter ablation of the cavotricuspid isthmus is an effective therapy for typical atrial flutter (AFL), however, the long-term recurrence of AFL and early or late occurrence of atrial fibrillation (AF) are not well defined. This study investigated the long-term (up to 68 months) outcome of patients with typical AFL after catheter ablation of the cavotricuspid isthmus. This study included 380 patients with typical AFL, who received linear ablation of the cavotricuspid isthmus. They were followed up at the outpatient clinic. A questionnaire was used to evaluate the symptoms suggestive of tachyarrhythmias, and 12-lead ECG, Holter monitoring and event recorders were used to confirm the diagnosis of tachyarrhythmias. At the end of study, 47 patients lost follow-up, so that 333 patients were enrolled into final analysis. Ten (3%) patients had failed ablation of typical AFL. Univariate analysis showed that left atrial dimension was the only factor related to failed ablation. During the long-term follow-up period of 29 +/- 17 months (range 7 to 68 months), 29 (9%) patients had recurrent AFL, including 15 with typical and 14 with atypical AFL. Univariate and multivariate analyses showed that incomplete isthmus block and inducible atypical AFL were the independent predictors of recurrent typical and atypical AFL, respectively. One hundred and two (31%) patients developed AF, including 48 with early occurrence of AF (within 3 months after ablation), and 54 with late occurrence of AF (greater than 3 months). Univariate and multivariate analyses showed that prior history of AF and inducible AF were independent predictors of early occurrence of AF, and prior history of AF was the only independent predictor of late occurrence of AF. Linear ablation of the cavotricuspid isthmus is an effective therapy with low recurrence rate for patients with typical AFL. However, one-third patients had early or late occurrence of AF.

Effect of postoperative atrial fibrillation on length of stay after cardiac surgery (the postoperative atrial fibrillation in cardiac surgery study [PACS 2

Atrial fibrillation (AF) after cardiac surgery is thought to increase length of stay (LOS). A clinical pathway focused on the management of postoperative AF, including prophylaxis with β blockers, was implemented to assess the effect of AF on LOS after cardiac surgery. Data were obtained on consecutive cardiac surgery patients in preoperative normal sinus rhythm, no prior history of AF, and no chronic antiarrhythmic therapy from January to May 1995 (control) and November 1996 to June 1997 (pathway). Statistical analysis was performed to assess the effect of postoperative AF on the LOS, clinical outcomes, and cost after cardiac surgery. Despite the clinical pathway, the LOS (7 days for both periods; p = 0.12) and incidence of AF (28.9% vs 28.4%; p = 0.92) remained unchanged. Unadjusted direct costs were 15% higher in the pathway period (p <0.001). Increased rates of β-blocker therapy had a marginal effect on the incidence of postoperative AF, except in the group who only underwent primary coronary artery bypass graft surgery (31.2% vs 25.3%; p = 0.31). Multivariate analysis revealed that AF contributed only 1 to 1.5 days to the LOS. Thus, this investigation represents the most recent analysis of the effects of postoperative AF on LOS, clinical outcomes, and cost after cardiac surgery. Unlike prior studies, the impact of postoperative AF is less prominent in the current era of cardiac surgical care regardless of the presence of a clinical pathway addressing AF.

Prevention of stroke in chronic and recurrent atrial fibrillation: role of the emergency department in identification of "at-risk" patients.

The objective was to determine the proportion of patients presenting to the Emergency Department (ED) in atrial fibrillation (AF) who are at high risk of thromboembolic stroke as defined by the American Heart Association and who might benefit from anticoagulation therapy. We enrolled all patients identified as having AF between 28th June 1999 and 26th March 2000. Data collected included demographic information, presenting complaint, discharge diagnosis, risk factors for thromboembolic stroke, contraindications to anticoagulation (as defined by the Stroke Prevention in AF Investigators), admission and discharge medications, and cardiac rhythm on presentation and at discharge. 193 patients were identified within the study period. Two patient histories were not available for review. 121 patients had a prior history of AF. Of these, 65 patients were at high risk for thromboembolic stroke and had no contraindication to anticoagulation therapy 43 (66%) were on Warfarin at presentation but 14 (22%) were on Aspirin and 8 (12%) were on neither. 34% of patients with chronic atrial fibrillation presenting to the ED, at high risk of thromboembolic stroke and without contra-indication to anticoagulation, were not anticoagulated on presentation. ED attendance provides an opportunity for intervention for the prevention of stroke in this group.

New transient ischemic attack and stroke: outpatient management by primary care physicians.

Patients with transient ischemic attack (TIA) or stroke frequently first contact their primary care physician rather than seeking care at a hospital emergency department. The purpose of the present study was to identify a group of patients seen by primary care physicians in an office setting for a first-ever TIA or stroke and characterize their evaluation and management. Practice audit based on retrospective, structured medical record abstraction from 27 primary care medical practices in 2 geographically separate communities in the eastern United States. Ninety-five patients with a first-ever TIA and 81 with stroke were identified. Seventy-nine percent of those with TIA vs 88% with stroke were evaluated on the day their symptoms occurred (P =.12). Only 6% were admitted to a hospital for evaluation and treatment on the day of the index visit (2% TIA; 10% stroke; P =.03); only an additional 3% were admitted during the subsequent 30 days. Specialists were consulted for 45% of patients. A brain imaging study (computed tomography or magnetic resonance imaging) was ordered on the day of the index visit in 30% (23% TIA, 37% stroke; P =.04), regardless of whether the patient was referred to a specialist. Carotid ultrasound studies were obtained in 28% (40% TIA, 14% stroke; P<.001), electrocardiograms in 19% (18% TIA, 21% stroke; P =.60), and echocardiograms in 16% (19% TIA, 14% stroke; P =.34). Fewer than half of patients with a prior history of atrial fibrillation (n = 24) underwent anticoagulation when evaluated at the index visit. Thirty-two percent of patients (31% TIA, 33% stroke; P =.70) were not hospitalized and had no evaluations performed during the first month after presenting to a primary care physician with a first TIA or stroke. Of these patients, 59% had a change in antiplatelet therapy on the day of the index visit. Further primary care physician education regarding the importance of promptly and fully evaluating patients with TIA or stroke may be warranted, and barriers to implementation of established secondary stroke prevention strategies need to be carefully explored. Arch Intern Med. 2000;160:2941-2946

Quantitative assessment of the spatial organization of atrial fibrillation in the intact human heart.

Atrial activation during atrial fibrillation (AF) is frequently described as random or chaotic. We propose that activation during AF is constrained by the principles of reentrant excitation; that these constraints impart a measurable spatial organization to activation during AF; and that the distance over which activation sequences remain well correlated can be readily measured and related both to the propensity of AF to sustain itself as well as to atrial tissue wavelength. We describe a novel signal-processing technique that quantifies the correlation in activation sequences recorded from five equally spaced sites in the right atrium in patients undergoing electrophysiology studies. In 20 patients in AF (12 with paroxysmal AF, 5 with chronic AF, and 3 with no clinical history of AF), the average correlation was 0.54 +/- 0.12 at 11 mm and 0.32 +/- 0.11 at 44 mm, compared with 0.95 +/- .023 and 0.91 +/- .023 in sinus rhythm. In AF, the correlation versus distance relation was monotonically decreasing, well fit by a decaying exponential function. The space constant of this exponential function, termed the activation space constant, provides a single objective metric of the spatial organization of activation during AF. The mean activation space constant for the group was 2.6 +/- 1.15 cm. Chronic AF had the lowest mean activation space constant (1.84 +/- 0.36 cm) and AF in patients with no prior history of AF had the highest (3.06 +/- 0.40 cm) (P < .05), with paroxysmal AF characterized by intermediate values (2.80 +/- 1.4 cm). Using a novel method to measure the spatial organization of atrial activation during AF, we have demonstrated that AF in the intact human heart is organized over a length scale consistent with reentrant excitation. Preliminary results suggest a relationship between measured spatial organization and the clinical course of the arrhythmia. Further work is needed to determine whether measurement of spatial organization may be useful in prospective patient-specific selection of therapeutic options.

Atrial Fibrillation After Implantable Cardioverter Defibrillator Implantation

Atrial fibrillation is a reported complication of automatic defibrillator implantation. Its incidence, risk factors, time-course, and complications have not been well-defined. Accordingly, data from 117 patients who underwent defibrillator implantation via a thoracotomy (n = 71) or nonthoracotomy (n = 46) approach were reviewed. To identify risk factors, 15 variables of potential predictive value were chosen and analyzed. Atrial fibrillation developed in 26/117 patients (22%) during the early postoperative period and all but one of these 26 patients had undergone thoracotomy (P < 0.001). Patients who developed atrial fibrillation tended to be older than those who did not (63 +/- 2 vs 58 +/- 2 years, P = 0.04) and more frequently had a prior history of paroxysmal atrial fibrillation (31% vs 10%, P = 0.02). They were also less likely to be taking Class I or III antiarrhythmic drugs (1/26 vs 24/91, P = 0.01). By multivariate analysis, operative approach (P < 0.001), the absence of antiarrhythmic drug therapy (P = 0.006), and a prior history of atrial fibrillation (P = 0.003) were significant independent variables. Digoxin neither prevented the occurrence of atrial fibrillation nor slowed the maximal ventricular response. The mortality and complication rates did not differ between the two groups. The major adverse effect of postimplant atrial fibrillation was automatic defibrillator discharge; six patients received between 1 and 11 discharges for atrial fibrillation with rapid ventricular rates.

Cardiac Pacing and Atrial Arrhythmias

Pacemaker patients frequently have concomitant atrial tachyarrhythmias, most importantly atrial fibrillation, because numerous underlying electrical or structural diseases can potentiate both conditions. DDD pacing (or atrial) appears superior to VVI in limiting the occurrence of atrial fibrillation and its associated negative sequela. Sick sinus syndrome, a prior history of atrial fibrillation, and advanced age predispose patients with DDD devices to postimplant atrial fibrillation, yet the majority of these high-risk patients are manageable in DDD throughout their follow-up. DDD patients at significant risk for developing atrial arrhythmias require special attention regarding the selection and programming of their devices. Rate modulation, higher lower rate limits, special approaches toward upper rate limit management, and antitachycardia capabilities may all be important aspects in their management. The combined use of AV node ablation and ventricular or DDD pacing to manage patients with refractory atrial tachyarrhythmias is becoming an increasingly accepted therapeutic approach.

DDD pacing mode survival in patients with a dual-chamber pacemaker

Dual-chamber (DDD) pacing mode survival was assessed by reviewing 486 consecutive initial transvenous DDD pacemaker implantations between December 1981 and December 1988 inclusive, with a mean follow-up time of 33 months. The patients' mean age was 71.4 years and 55% were male; 38% had dominant sinoatrial and 62% had dominant atrioventricular (AV) node disease. Nineteen patients (4%) underwent secondary operative intervention for lead dislodgment (n = 11), lead or pulse generator malfunction (n = 6) or infection (n = 2).During follow-up, 87 patients (18%) had their device permanently reprogrammed out of the DDD mode and 10 others (2%) required temporary reprogramming out of this mode; 12 patients who required device reprogramming were managed in other dual-chamber or atrial pacing modes. Reasons for reprogramming included atrial fibrillation (n = 48; 10%); loss of atrial sensing (n = 26; 5%); recurrent “endless loop” tachycardia (n = 5; 1%); lead dislodgment without repositioning (n = 4; 1%); pulse generator malfunction (n = 1; 1%) and other (n = 5; 1%).The occurrence of atrial fibrillation was associated with dominant sinoatrial disease and a prior history of atrial fibrillation; 19% of atrial sensing loss was attributable to early or faulty pacemaker technology. The DDD mode survival rate at 1, 2, 3, 4 and 5 years was, respectively, 90%, 88%, 84%, 79% and 78%.It is concluded that 1) 4% of DDD pacemaker implants required secondary surgical intervention; 2) 82% of implanted pacemakers remained in the DDD mode throughout follow-up; 3) onset of atrial fibrillation or loss of atrial sensing accounted for 73% of the mode changes; 4) 10% of the permanent mode changes were directly related to early or defective pacemaker technology; and 5) DDD pacing remains a very reliable and effective long-term therapy in the majority of patients with a DDD pacemaker.

Clinical Predictors and Natural History of Atrial Fibrillation in Patients with DDD Pacemakers

Effective DDD pacing requires that patients remain free of atrial fibrillation (AF). Four hundred eighty-nine consecutive patients undergoing initial transvenous DDD implants were reviewed to determine the incidence of postimplant AF in this population and to assess what factors, known at implant, predicted the later development of AF. The variables analyzed included age, sex, indication for implant (dominant SA or AV node disease), history of AF, atrial electrogram characteristics and pacing threshold, and the status of retrograde conduction. Forty-eight patients (9.8%) developed AF a mean of 23 months postimplant, and 11 of these patients returned to sinus rhythm and were managed once again in DDD for significant periods. A prior history of AF and the presence of dominant sinoatrial disease were far more prevalent in the patients who developed AF (P less than 0.001) though the vast majority of patients with these two independent risk factors remained in sinus rhythm through much or all of their follow-up period. We conclude that the incidence of AF is not of a magnitude to preclude DDD pacing in the vast majority of patients in sinus rhythm at implant.

Prospective evaluation of transesophageal pacing for the interruption of atrial flutter

purpose: Although transesophageal pacing has been used successfully for the interruption of cardiac arrhythmias, the efficacy of this technique for the interruption of spontaneous atrial flutter remains poorly defined. The utility of transesophageal pacing to interrupt atrial flutter that was persistent despite standard antiarrhythmic drug therapy (mean duration: 70.3 days; range: one day to more than 365 days) was studied prospectively in 39 consecutive patients. patients and methods: After written informed consent was obtained from each patient, transesophageal pacing was performed with a programmable stimulator, using the distal electrode as the cathode and the proximal electrode as the anode. All patients continued to receive a type 1 antiarrhythmic drug or amiodarone throughout the period of transesophageal pacing. The response to transesophageal pacing was classified as follows: (1) direct conversion; (2) indirect conversion; or (3) failure to interrupt atrial flutter. results: The mean stimulus amplitude and pulse duration required for atrial capture were 19.8 ± 7.5 mA and 18.4 ± 7.9 msec. Atrial flutter was successfully converted to sinus rhythm by transesophageal pacing in 82% of patients. In 38% of patients, atrial flutter was converted directly to sinus rhythm without another intervening arrhythmia (direct conversion). The mean pacing rate required for direct conversion was 341 ± 27 beats/minute. In 44% of patients, the cycle length of atrial flutter was accelerated to less than 180 msec or was converted to atrial fibrillation with spontaneous conversion to sinus rhythm within 24 hours (mean 8.4 ± 9.3 hours, indirect conversion). The mean pacing rate inducing accelerated atrial flutter or transient atrial fibrillation was 372 ± 61 beats/minute (p = NS compared to direct conversion). Atrial flutter was not interrupted or atrial fibrillation was induced that did not spontaneously convert to sinus rhythm within 24 hours in an additional seven patients (18%). The underlying cardiac disease, age, previous drug therapy, atrial size, atrial flutter cycle length, history of prior atrial fibrillation, left ventricular function, and concomitant medical illnesses did not predict the efficacy of transesophageal pacing. conclusion: The present study suggests that transesophageal pacing is highly effective for interrupting spontaneous atrial flutter that does not terminate with standard antiarrhythmic drug therapy.