Background Atrial fibrillation, the most common sustained cardiac arrhythmia and a major cause of stroke, results from simultaneous reentrant wavelets. Its spontaneous initiation has not been studied. Methods We studied 45 patients with frequent episodes of atrial fibrillation (mean [±SD] duration, 344±326 minutes per 24 hours) refractory to drug therapy. The spontaneous initiation of atrial fibrillation was mapped with the use of multielectrode catheters designed to record the earliest electrical activity preceding the onset of atrial fibrillation and associated atrial ectopic beats. The accuracy of the mapping was confirmed by the abrupt disappearance of triggering atrial ectopic beats after ablation with local radio-frequency energy. Results A single point of origin of atrial ectopic beats was identified in 29 patients, two points of origin were identified in 9 patients, and three or four points of origin were identified in 7 patients, for a total of 69 ectopic foci. Three foci were in the right atrium...

https://www.nejm.org/doi/pdf/10.1056/NEJM199809033391003

Spontaneous Initiation of Atrial Fibrillation by Ectopic Beats Originating in the Pulmonary Veins

Jeffrey L. Anderson, MD, FACC, FAHA, Chair 

Jonathan L. Halperin, MD, FACC, FAHA, Chair-Elect 

Nancy M. Albert, PhD, RN, FAHA

Biykem Bozkurt, MD, PhD, FACC, FAHA

Ralph G. Brindis, MD, MPH, MACC

Mark A. Creager, MD, FACC, FAHA[#][1]

Lesley H. Curtis, PhD, FAHA

David DeMets, PhD[#][1]

Robert A

/pdf/2014-aha-acc-hrs-guideline-for-the-management-of-patients-1v8ficsqox.pdf

2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society

Guidelines summarize and evaluate all currently available evidence on a particular issue with the aim of assisting physicians in selecting the best management strategy for an individual patient suffering from a given condition, taking into account the impact on outcome, as well as the risk–benefit ratio of particular diagnostic or therapeutic means. Guidelines are no substitutes for textbooks. The legal implications of medical guidelines have been discussed previously.

A large number of Guidelines have been issued in recent years by the European Society of Cardiology (ESC) as well as by other societies and organizations. Because of the impact on clinical practice, quality criteria for development of guidelines have been established in order to make all decisions transparent to the user. The recommendations for formulating and issuing ESC Guidelines can be found on the ESC Web Site (http://www.escardio.org/guidelines-surveys/esc-guidelines/about/Pages/rules-writing.aspx).

In brief, experts in the field are selected and undertake a comprehensive review of the published evidence for management and/or prevention of a given condition. A critical evaluation of diagnostic and therapeutic procedures is performed, including assessment of the risk–benefit ratio. Estimates of expected health outcomes for larger societies are included, where data exist. The level of evidence and the strength of recommendation of particular treatment options are weighed and graded according to pre-defined scales, as outlined in Tables 1 and 2 .

View this table:

Table 1 
Classes of recommendations



View this table:

Table 2 
Levels of evidence



The experts of the writing panels have provided disclosure statements of all relationships they may have that might be perceived as real or potential sources of conflicts of interest. These disclosure forms are kept on file at the European Heart House, headquarters of the ESC. Any changes in conflict of interest that arise during the writing period must be notified to the ESC. The Task Force report received its entire financial support from …

/pdf/guidelines-for-the-management-of-atrial-fibrillation-the-1cikaj4630.pdf

Guidelines for the management of atrial fibrillation The Task Force for the Management of Atrial Fibrillation of the European Society of Cardiology (ESC)

The Task Force for the management of atrial fibrillation of the European Society of Cardiology (ESC)  

Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC  

Endorsed by the European Stroke Organisation (ESO)

/pdf/2016-esc-guidelines-for-the-management-of-atrial-ba0601yb9m.pdf

2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS

/pdf/2016-esc-guidelines-for-the-management-of-atrial-36b2cidm1x.pdf

2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS: The Task Force for the management of atrial fibrillation of the European Society of Cardiology (ESC). Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC. Endorsed by the European Stroke Organisation (ESO)

Background Atrial fibrillation cannot always be converted to sinus rhythm by transthoracic electrical cardioversion. We examined the effect of ibutilide, a class III antiarrhythmic agent, on the energy requirement for atrial defibrillation and assessed the value of this agent in facilitating cardioversion in patients with atrial fibrillation that is resistant to conventional transthoracic cardioversion. Methods One hundred patients who had had atrial fibrillation for a mean (±SD) of 117±201 days were randomly assigned to undergo transthoracic cardioversion with or without pretreatment with 1 mg of ibutilide. We designed a step-up protocol in which shocks at 50, 100, 200, 300, and 360 J were used for transthoracic cardioversion. If transthoracic cardioversion was unsuccessful in a patient who had not received ibutilide pretreatment, ibutilide was administered and transthoracic cardioversion attempted again. Results Conversion to sinus rhythm occurred in 36 of 50 patients who had not received ibutilide (72 ...

Facilitating transthoracic cardioversion of atrial fibrillation with ibutilide pretreatment.

Background In some patients with atrial fibrillation, the ventricular rate may be difficult to control with medications. We evaluated a radiofrequency catheter technique to modify atrioventricular conduction in atrial fibrillation in order to control the ventricular rate without creating pathologic atrioventricular block. Methods We studied 19 consecutive patients with atrial fibrillation and uncontrolled ventricular rates refractory to drug therapy. They had had atrial fibrillation for a mean (±SD) of 5.5 ±4.9 years, had had 4.9 ±0.9 unsuccessful drug trials, and were 62 ±15 years old. Before the procedure, the maximal ventricular rate during exercise was 180 ±39 beats per minute. A total of 11 ±5 radiofrequency-energy applications were delivered to the posterior septal or midseptal right atrium, near the ostium of the coronary sinus. Results Successful control of the ventricular rate without pathologic atrioventricular block was achieved in 14 of the 19 patients (74 percent). Persistent third-degree atr...

Radiofrequency Catheter Modification of Atrioventricular Conduction to Control the Ventricular Rate during Atrial Fibrillation

Electrocardiographic artifact can simulate ventricular tachycardia. The literature regarding electrocardiographic artifact is limited to case reports,1–7 proposed classifications,8,9 and diagnostic criteria.10 There is little information regarding the clinical implications of the misdiagnosis of artifact as ventricular tachycardia. We describe 12 patients who underwent unnecessary diagnostic or therapeutic interventions as a result of such a misdiagnosis. Methods We included in this series patients who were seen in consultation by a cardiac electrophysiologist at our institution between 1995 and 1999 and who underwent a diagnostic procedure or received treatment unnecessarily, solely as a result of the misdiagnosis of artifact as . . .

Clinical consequences of electrocardiographic artifact mimicking ventricular tachycardia

BACKGROUNDJunctional ectopy may occur during radiofrequency (RF) catheter ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia (AVNRT). The purpose of the present study was to characterize this junctional ectopy quantitatively.METHODS AND RESULTSThe subjects of this study were 52 consecutive patients with AVNRT who underwent slow pathway ablation and 5 additional patients included retrospectively because they had developed high-degree atrioventricular (AV) block during the procedure. A combined anatomic and electrogram mapping approach was used for slow pathway ablation, and AVNRT was successfully eliminated in all patients. In the group of 52 consecutive patients, the incidence of junctional ectopy was significantly higher during 52 effective applications of RF energy than during 366 ineffective applications (100% versus 65%, P < .001). Compared with ineffective RF energy applications, successful RF energy applications had a significantly longer duration of individua...

Analysis of junctional ectopy during radiofrequency ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia.

BACKGROUND Previous studies have shown that the size of lesions produced by radiofrequency catheter ablation correlates with the temperature and surface area of the electrode-tissue interface. The purpose of the present study was to compare the effects of ablation using very large distal electrodes (8F, 8 and 12 mm long) with those made by a conventional radiofrequency ablation catheter (distal electrode 8F, 4 mm long). METHODS AND RESULTS Each catheter had a thermistor in the tip of the distal electrode. Radiofrequency energy (500 kHz) was supplied by a generator that continuously monitored temperature and produced up to 100 W. In 10 dogs, each of the three ablation catheters were introduced percutaneously and positioned under fluoroscopic guidance at disparate left ventricular endocardial sites. Radiofrequency power output was titrated to achieve a temperature of 80 degrees C for 60 seconds at each ablation site. The power required to produce a steady-state temperature of 80 degrees C was directly proportional to electrode size (15 +/- 7, 46 +/- 15, and 62 +/- 32 W using the 4-mm-, 8-mm-, and 12-mm-long electrodes, respectively). Lesions produced by the 8-mm electrode were nearly twice as deep (11 +/- 2.4 versus 6 +/- 1.2 mm, P < .001) and four times as large (905 +/- 410 versus 210 +/- 100 mm3, P < .001) as those made with a conventional 4-mm electrode. Lesions produced by the 12-mm electrode were intermediate in size (depth, 8 +/- 1.2 mm; volume, 465 +/- 225 mm3) and sometimes were associated with charring and crater formation. Ablation with the larger electrodes caused a drop in arterial pressure and more ventricular ectopy than ablation using a 4-mm distal electrode. CONCLUSIONS Thermistor-equipped elongated ablation electrodes coupled to high-power outputs can reproducibly produce lesions approximately 1 cm in diameter. This system may prove useful for ablation of ventricular tachycardias in patients with coronary artery disease.

S A Strickberger

Papers

Facilitating transthoracic cardioversion of atrial fibrillation with ibutilide pretreatment.

Radiofrequency Catheter Modification of Atrioventricular Conduction to Control the Ventricular Rate during Atrial Fibrillation

Clinical consequences of electrocardiographic artifact mimicking ventricular tachycardia

Analysis of junctional ectopy during radiofrequency ablation of the slow pathway in patients with atrioventricular nodal reentrant tachycardia.

Temperature-guided radiofrequency catheter ablation with very large distal electrodes.