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Concept: Atrial flutter

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OBJECTIVE: Describe the electrophysiological characteristics in subjects with asymptomatic Wolff-Parkinson-White with sports activities or high professional responsibility. METHODS: Nineteen subjects, mean age 33±13 years (group A). The electrophysiological characteristics were compared with a matched group with symptomatic WPW (group B). RESULTS: At baseline the anterograde refractory period and the anterograde conduction 1:1 over the accessory pathway were longer in group A (300±48ms vs 262±32ms, p<0.05 and 355±108ms vs 307±86ms, p<0.05), respectively. None of group A had a anterograde refractory period<250ms and 58% showed absence of retrograde conduction over the accessory pathway vs 4% of group B (p<0.001). Induction of tachycardia was significantly less in group A (5%) than in group B (92%) (p<0.001). Atrial fibrillation was induced in only one of group A vs 32% of group B (p<0.001). CONCLUSION: We confirm the benign electrophysiological characteristics in asymptomatic compared to symptomatic subjects. Poor anterograde conduction along with absence of retrograde conduction explains the low frequency of tachyarrhythmias and would not support the routine investigation of all asymptomatic subjects. But, due to possible consequences, remains the systematic indication for preventive ablation in the subgroup of asymptomatic subjects with sporting activities or high professional responsibility.

Concepts: Atrial fibrillation, Cardiac electrophysiology, Supraventricular tachycardia, Atrial flutter, Orgasm, Asymptomatic, Tachycardia, Wolff-Parkinson-White syndrome

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AIMS: Orthodromic atrioventricular reentrant tachycardia (ORT) is the most common arrhythmia at electrophysiological study (EPS) in patients with pre-excitation. The purpose of the study was to determine the clinical significance and the electrophysiological characteristics of patients with inducible antidromic tachycardia (ADT).METHODS AND RESULTS: Electrophysiological study was performed in 807 patients with a pre-excitation syndrome in control state and after isoproterenol. Antidromic tachycardia was induced in 63 patients (8%). Clinical and electrophysiological data were compared with those of 744 patients without ADT. Patients with and without ADT were similar in term of age (33 ± 18 vs. 34 ± 17), male gender (68 vs. 61%), clinical presentation with spontaneous atrioventricular reentrant tachycardia (AVRT) (35 vs. 42%), atrial fibrillation (AF) (3 vs. 3%), syncope (16 vs. 12%). In patients with induced ADT, asymptomatic patients were less frequent (24 vs. 37%; <0.04), spontaneous ADT and spontaneous malignant form more frequent (8 vs. 0.5%; <0.001) (16 vs. 6%; <0.002). Left lateral accessory pathway (AP) location was more frequent (51 vs. 36%; P < 0.022), septal location less frequent (40 vs. 56%; P < 0.01). And 1/1 conduction through AP was more rapid. Orthodromic AVRT induction was as frequent (55.5 vs. 55%), but AF induction (41 vs. 24%; P < 0.002) and electrophysiological malignant form were more frequent (22 vs. 12%; P < 0.02). The follow-up was similar; four deaths and three spontaneous malignant forms occurred in patients without ADT. When population was divided based on age (<20/≥20 years), the older group was less likely to have criteria for malignant form.CONCLUSION: Antidromic tachycardia induction is rare in pre-excitation syndrome and generally is associated with spontaneous or electrophysiological malignant form, but clinical outcome does not differ.

Concepts: Atrial fibrillation, Supraventricular tachycardia, Atrial flutter, Neurophysiology, Asymptomatic, Tachycardia, Wolff-Parkinson-White syndrome, AV nodal reentrant tachycardia

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The purpose of this study was to investigate the frequency and clinical impact of incomplete left atrial appendage (LAA) sealing and consequent peri-device residual blood flow in patients undergoing percutaneous LAA closure with the Watchman device (Atritech, Inc., Plymouth, Minnesota).

Concepts: Heart, Stroke, Atrial fibrillation, Warfarin, Atrial flutter, Anticoagulant, Left atrial appendage occlusion, Left atrial appendage

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BACKGROUND: Many patients who develop atrial fibrillation (AF) will experience a worsening of their arrhythmia over time. The optimal time to proceed with catheter ablation during the disease course is unknown. Further, it is unknown if delays in treatment will negatively influence outcomes. METHODS: A total of 4,535 consecutive patients who underwent an AF ablation procedure that had long-term established care within an integrated health care system were evaluated. Recursive partitioning was used to determine categories associated with changes in risk from the time of first AF diagnosis to first AF ablation: 1:30-180(n=1,152), 2:181-545(n=856), 3:546-1825(n=1,326), 4:>1825(n=1,201) days). Outcomes evaluated include 1 year AF recurrence, stroke, heart failure hospitalization, and death. RESULTS: With increasing time to treatment, surprisingly patients were older (1: 63.7±11.1, 2: 62.6±11.8, 3: 66.4±10.2, 4: 67.6±9.7, p<0.0001) and had more hypertension (1:53.0%, 2:59.0%, 3:53.8%, 4:39.0%, p<0.0001). For each strata of time increase, there was a direct increase of 1 year AF recurrence (1:19.4%, 2: 23.4%, 3:24.9%, 4:24.0%, p-trend = 0.02). After adjustment, clinically significant differences in risk of recurrent AF were found when compared to the 30-180 day time category: 181-545: odd ratio(OR)=1.23, p=0.08; 546-1825: OR=1.27, p=0.02; and >1825: OR=1.25, p=0.05. No differences were observed for 1 year stroke among the groups. Death (1:2.1%, 2:3.9%, 3:5.7%, 4:4.4%, p-trend=0.001) and heart failure hospitalization (1:2.6%, 2:4.1%, 3:5.4%, 4:4.4%, p-trend=0.009) rates at 1 year were higher in the most delayed groups. CONCLUSIONS: Delays in treatment with catheter ablation impact procedural success rates independent of temporal changes to the AF subtype at ablation.

Concepts: Hypertension, Cardiology, Heart, Stroke, Atrial fibrillation, Cardiac electrophysiology, Atrial flutter, Object-oriented programming

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Background Current guidelines recommend pulmonary-vein isolation by means of catheter ablation as treatment for drug-refractory paroxysmal atrial fibrillation. Radiofrequency ablation is the most common method, and cryoballoon ablation is the second most frequently used technology. Methods We conducted a multicenter, randomized trial to determine whether cryoballoon ablation was noninferior to radiofrequency ablation in symptomatic patients with drug-refractory paroxysmal atrial fibrillation. The primary efficacy end point in a time-to-event analysis was the first documented clinical failure (recurrence of atrial fibrillation, occurrence of atrial flutter or atrial tachycardia, use of antiarrhythmic drugs, or repeat ablation) following a 90-day period after the index ablation. The noninferiority margin was prespecified as a hazard ratio of 1.43. The primary safety end point was a composite of death, cerebrovascular events, or serious treatment-related adverse events. Results A total of 762 patients underwent randomization (378 assigned to cryoballoon ablation and 384 assigned to radiofrequency ablation). The mean duration of follow-up was 1.5 years. The primary efficacy end point occurred in 138 patients in the cryoballoon group and in 143 in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 34.6% and 35.9%, respectively; hazard ratio, 0.96; 95% confidence interval [CI], 0.76 to 1.22; P<0.001 for noninferiority). The primary safety end point occurred in 40 patients in the cryoballoon group and in 51 patients in the radiofrequency group (1-year Kaplan-Meier event rate estimates, 10.2% and 12.8%, respectively; hazard ratio, 0.78; 95% CI, 0.52 to 1.18; P=0.24). Conclusions In this randomized trial, cryoballoon ablation was noninferior to radiofrequency ablation with respect to efficacy for the treatment of patients with drug-refractory paroxysmal atrial fibrillation, and there was no significant difference between the two methods with regard to overall safety. (Funded by Medtronic; FIRE AND ICE ClinicalTrials.gov number, NCT01490814 .).

Concepts: Atrial fibrillation, Cardiac electrophysiology, Supraventricular tachycardia, Atrial flutter, Amiodarone, Digoxin, Radiofrequency ablation, Wolff-Parkinson-White syndrome

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Focal atrial tachycardias arise preferentially from specific locations within the atria. Careful analysis of the P wave can provide useful information about the chamber and likely site of origin within that chamber. Macro-reentrant atrial flutter also tends to occur over a limited number of potential circuits. In this case, the ECG usually gives a guide to the chamber of origin, but unless it shows a specific morphology it is less useful in delineating the circuit involved. Nonetheless, prior knowledge of the likely chamber of origin helps to plan the ablation strategy.

Concepts: Atrial fibrillation, Supraventricular tachycardia, Atrial flutter, Circuit, The Circuit, Grammatical number, The Chamber

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Obesity is a risk factor for atrial fibrillation, which in turn is associated with stroke, heart failure, and increased all-cause mortality.

Concepts: Hypertension, Heart, Obesity, Stroke, Atrial fibrillation, Atrial flutter, Bariatric surgery, Gastric bypass surgery

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-Atrial fibrillation (AF) requires arrhythmogenic changes in atrial ion channels/receptors and usually altered atrial structure. AF is commonly treated with antiarrhythmic drugs (AADs); the most effective block many ion channels/receptors. Modest efficacy, intolerance, and safety concerns limit current AADs. We hypothesized that combining agents with multiple anti-AF mechanisms at reduced individual drug doses might produce synergistic efficacy plus better tolerance/safety.

Concepts: Atrial fibrillation, Cardiac electrophysiology, Atrial flutter, Amiodarone, Digoxin, Flecainide, Procainamide, Dronedarone

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Acute stroke care includes cardiac rhythm monitoring in the first 24 hours. The method of monitoring varies, as do the reported findings. The nurses' role in this process can be intensive, including primary response and review of all data. Competency is critical as the acute stroke setting can be associated with life-threatening dysrhythmias as well as the detection of atrial fibrillation that affects therapy. Limited studies exist to evaluate the effectiveness of a unit-based cardiac monitoring system for which the bedside nurse has primary responsibility.

Concepts: Heart, Stroke, Atrial fibrillation, Computer program, Atrial flutter, Nurse, Cardiac monitoring

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Obesity is repeatedly emphasized as a risk factor for atrial fibrillation or flutter (AF). However, the underlying evidence may be questioned, as the obvious correlations between various anthropometric measures hamper identification of the characteristics that are biologically driving AF risk, and recent studies suggest that fat carries limited or no independent risk of AF.

Concepts: Heart, Atrial fibrillation, Anthropometry, Atrial flutter, Body shape