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Atropine-facilitated electrical cardioversion of persistent atrial fibrillation
Percutaneous Pericardial Instrumentation for EndoEpicardial Mapping of Previously Failed Ablations
tempted with monophasic shocks of up to 360J (254 patients) or biphasic shocks of up to 200J (110 patients). If two maximum-output shocks were ineffective, 1 mg of atropine was administered and the maximum-output shock was repeated. If necessary, an additional 1 mg of atropine was administered, followed by a final maximum-output shock. Failures of cardioversion included both the inability to restore sinus rhythm and immediate recurrence of AF (IRAF) in ⬍1 minute post-cardioversion. Results: The cardioversion failure rate was 13% with monophasic shocks and 15% with biphasic shocks. Among 49 patients who failed cardioversion, repeat cardioversion after 1–2 mg of atropine resulted in successful cardioversion in 40 patients (82%). Conclusions: Pretreatment with atropine facilitates the successful transthoracic cardioversion of patients with AF who fail to convert with maximum-output monophasic or biphasic shocks. Perspective: This study does not provide any insight into how atropine facilitated the cardioversion of AF. In theory, atropine might prevent post-cardioversion episodes of IRAF that are bradycardia-related, but would not affect the defibrillation threshold. Other studies have demonstrated that ibutilide also facilitates the conversion of AF with transthoracic shocks. Ibutilide not only prevents episodes of IRAF but also lowers the defibrillation threshold, and therefore may be more useful than atropine. FM
Schweikert RA, Saliba WI, Tomassoni G, et al. Circulation 2003; 108:1329 –35. Study Question: How often is epicardial ablation effective in patients with ventricular tachycardia (VT) or supraventricular tachycardia (SVT) who have failed endocardial catheter ablation? Methods: The subjects of this study were 48 consecutive patients (mean age 45 years) who had undergone unsuccessful endocardial radiofrequency catheter ablation of VT or SVT. During electrophysiologic studies, a 7F ablation catheter was introduced percutaneously into the pericardial space and used for epicardial mapping and radiofrequency ablation. The patients were followed for ⱖ1 year postablation. Results: Among 30 patients with VT, 20 did not have structural heart disease and 10 had an ischemic or dilated cardiomyopathy. Epicardial ablation of VT was successful in 17 patients (57%). Among 10 patients with an accessory pathway, epicardial ablation was successful in three patients who had a connection between the right atrial appendage and the right ventricle. Among four patients with inappropriate sinus tachycardia and four with atrial fibrillation/flutter, epicardial ablation was effective in only one. Overall, epicardial ablation was successful in 21/48 patients (44%). The only complication was transient pericarditis in three patients (6%). Conclusions: In patients who fail endocardial radiofrequency catheter ablation, a successful outcome sometimes can be achieved by ablation within the pericardial space, particularly in patients with ventricular tachycardia. Perspective: A potential risk of radiofrequency ablation in the pericardial space is injury to an epicardial coronary artery. This risk may be small because the blood flowing through a coronary artery serves as a heat sink that protects the arterial wall from heat-induced injury. However, it is possible that the risk is higher for arteries that are diseased because of restricted blood flow. Further evaluation of this risk by coronary arteriography pre-ablation and 1–2 years post-ablation will be needed. FM
Usefulness of Implantable Loop Recorders in Office-Based Practice for Evaluation of Syncope in Patients With and Without Structural Heart Disease Mason PK, Wood MA, Reese DB, Lobban JH, Mitchell MA, DiMarco JP. Am J Cardiol 2003;92:1127–9. Study Question: How useful is the implantable loop recorder (ILR) in routine office practice? Methods: An ILR was implanted in 43 patients with recurrent, unexplained syncope or near-syncope. Prior testing included a Holter monitor in 20 patients, event monitor in 16 patients, tilt table test in 32 patients, and electrophysiology test in 17 patients. Twenty-nine patients had structural heart disease. The mean duration of follow-up was 11 months. Results: Syncope/near-syncope recurred in 32 patients (74%) at a mean of 8 months post-implant. The cause was found to be a bradyarrhythmia in 12 patients (28%) and ventricular tachycardia in one patient (2%). The ILR ruled out an arrhythmia as the cause of symptoms in 19 patients (44%). The remaining 11 patients (26%) did not have recurrent symptoms. In four of the 13 patients eventually found to have an arrhythmic cause of symptoms, at least one recording during symptoms demonstrated only sinus rhythm. The yield of the ILR did not differ between patients with and without structural heart disease. There were no deaths or serious complications during follow-up.
Atropine-Facilitated Electrical Cardioversion of Persistent Atrial Fibrillation Kaluski E, Blatt A, Leitman M, Krakover R, Vered Z, Cotter G. Am J Cardiol 2003;92:1119 –22. Study Question: Is atropine useful in improving the outcome of transthoracic cardioversion of atrial fibrillation (AF)? Methods: Transthoracic cardioversion was performed in 364 patients with AF that had been present for 1–72 months. Their mean age was 68 years, their mean left atrial diameter was 4.8 cm and 88% of patients were being treated with either amiodarone or propafenone. Cardioversion was at-
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tempted with monophasic shocks of up to 360J (254 patients) or biphasic shocks of up to 200J (110 patients). If two maximum-output shocks were ineffective, 1 mg of atropine was administered and the maximum-output shock was repeated. If necessary, an additional 1 mg of atropine was administered, followed by a final maximum-output shock. Failures of cardioversion included both the inability to restore sinus rhythm and immediate recurrence of AF (IRAF) in ⬍1 minute post-cardioversion. Results: The cardioversion failure rate was 13% with monophasic shocks and 15% with biphasic shocks. Among 49 patients who failed cardioversion, repeat cardioversion after 1–2 mg of atropine resulted in successful cardioversion in 40 patients (82%). Conclusions: Pretreatment with atropine facilitates the successful transthoracic cardioversion of patients with AF who fail to convert with maximum-output monophasic or biphasic shocks. Perspective: This study does not provide any insight into how atropine facilitated the cardioversion of AF. In theory, atropine might prevent post-cardioversion episodes of IRAF that are bradycardia-related, but would not affect the defibrillation threshold. Other studies have demonstrated that ibutilide also facilitates the conversion of AF with transthoracic shocks. Ibutilide not only prevents episodes of IRAF but also lowers the defibrillation threshold, and therefore may be more useful than atropine. FM
Schweikert RA, Saliba WI, Tomassoni G, et al. Circulation 2003; 108:1329 –35. Study Question: How often is epicardial ablation effective in patients with ventricular tachycardia (VT) or supraventricular tachycardia (SVT) who have failed endocardial catheter ablation? Methods: The subjects of this study were 48 consecutive patients (mean age 45 years) who had undergone unsuccessful endocardial radiofrequency catheter ablation of VT or SVT. During electrophysiologic studies, a 7F ablation catheter was introduced percutaneously into the pericardial space and used for epicardial mapping and radiofrequency ablation. The patients were followed for ⱖ1 year postablation. Results: Among 30 patients with VT, 20 did not have structural heart disease and 10 had an ischemic or dilated cardiomyopathy. Epicardial ablation of VT was successful in 17 patients (57%). Among 10 patients with an accessory pathway, epicardial ablation was successful in three patients who had a connection between the right atrial appendage and the right ventricle. Among four patients with inappropriate sinus tachycardia and four with atrial fibrillation/flutter, epicardial ablation was effective in only one. Overall, epicardial ablation was successful in 21/48 patients (44%). The only complication was transient pericarditis in three patients (6%). Conclusions: In patients who fail endocardial radiofrequency catheter ablation, a successful outcome sometimes can be achieved by ablation within the pericardial space, particularly in patients with ventricular tachycardia. Perspective: A potential risk of radiofrequency ablation in the pericardial space is injury to an epicardial coronary artery. This risk may be small because the blood flowing through a coronary artery serves as a heat sink that protects the arterial wall from heat-induced injury. However, it is possible that the risk is higher for arteries that are diseased because of restricted blood flow. Further evaluation of this risk by coronary arteriography pre-ablation and 1–2 years post-ablation will be needed. FM
Usefulness of Implantable Loop Recorders in Office-Based Practice for Evaluation of Syncope in Patients With and Without Structural Heart Disease Mason PK, Wood MA, Reese DB, Lobban JH, Mitchell MA, DiMarco JP. Am J Cardiol 2003;92:1127–9. Study Question: How useful is the implantable loop recorder (ILR) in routine office practice? Methods: An ILR was implanted in 43 patients with recurrent, unexplained syncope or near-syncope. Prior testing included a Holter monitor in 20 patients, event monitor in 16 patients, tilt table test in 32 patients, and electrophysiology test in 17 patients. Twenty-nine patients had structural heart disease. The mean duration of follow-up was 11 months. Results: Syncope/near-syncope recurred in 32 patients (74%) at a mean of 8 months post-implant. The cause was found to be a bradyarrhythmia in 12 patients (28%) and ventricular tachycardia in one patient (2%). The ILR ruled out an arrhythmia as the cause of symptoms in 19 patients (44%). The remaining 11 patients (26%) did not have recurrent symptoms. In four of the 13 patients eventually found to have an arrhythmic cause of symptoms, at least one recording during symptoms demonstrated only sinus rhythm. The yield of the ILR did not differ between patients with and without structural heart disease. There were no deaths or serious complications during follow-up.
Atropine-Facilitated Electrical Cardioversion of Persistent Atrial Fibrillation Kaluski E, Blatt A, Leitman M, Krakover R, Vered Z, Cotter G. Am J Cardiol 2003;92:1119 –22. Study Question: Is atropine useful in improving the outcome of transthoracic cardioversion of atrial fibrillation (AF)? Methods: Transthoracic cardioversion was performed in 364 patients with AF that had been present for 1–72 months. Their mean age was 68 years, their mean left atrial diameter was 4.8 cm and 88% of patients were being treated with either amiodarone or propafenone. Cardioversion was at-
ACC CURRENT JOURNAL REVIEW Feb 2004
55