Success Rate Of Catheter Ablation Research Articles

Gender Differences of Electrophysiological Characteristics in Focal Atrial Tachycardia

Gender differences of supraventricular tachycardias such as atrioventricular nodal re-entry, atrioventricular re-entry, and atrial fibrillation have been reported. There is little evidence of the effect of gender on focal atrial tachycardia (FAT). The study consisted of 298 patients who were referred to this institution for radiofrequency catheter ablation of FAT from October 1992 to April 2008 and included 156 men (52%) and 142 women (48%). Men were significantly older than women (57.9 +/- 18.2 vs 47.2 +/- 19.0 years old, p <0.001). Women had more associated arrhythmias (17.0% vs 28.9%, p = 0.01), mostly due to an increased incidence of atrioventricular nodal re-entrant tachycardia. Men had more cardiovascular co-morbidities (19.9% vs 9.9%, p = 0.02), a mechanism of increased automaticity (19.1% vs 8.1%, p = 0.01), and nonparoxysmal tachycardia (14.7% vs 4.4%, p = 0.01). No gender differences were noted among FAT number, left atrial involvement, shortest tachycardia cycle, success rate of catheter ablation, or recurrence rate of FAT. Mean duration of follow-up was 63.2 +/- 47.5 months. Premenopausal women had a lesser cardiovascular co-morbidity (15.3% vs 4.3%, p = 0.04) and a greater incidence of a mechanism of increased automaticity (13.4% vs 2.9%, p = 0.03). In conclusion, gender differences in electrophysiologic characteristics were noted in FAT.

Catheter Ablation of Ventricular Tachycardia

The majority of ventricular tachycardias (VTs) occurs in patients with structural heart disease, predominantly coronary heart disease. Implantable cardioverter defibrillators (ICDs) are first-line therapy in patients with VT and structural heart disease. In patients who receive an ICD after a spontaneous sustained VT, recurrent VT episodes or an electrical storm are major problems. In addition, in patients with an ICD implanted for primary prevention of sudden cardiac death, 20% will experience at least one VT episode within 3-5 years after ICD implantation. Catheter ablation has a high acute success rate in eliminating clinical VT. However, several factors make catheter ablation of VT more difficult than ablation of supraventricular tachyarrhythmias. (1) The infarct region is often large. (2) The induced VT can be unstable or hemodynamically only poorly tolerated and therefore "unmappable". (3) Though most commonly located in the subendocardium, the critical VT zone can occasionally be epicardial or intramural in location. (4) In many cases, several reentrant circuits may coexist making ablation of a single form of VT a palliative procedure which does not obviate the risk of sudden death. Thus, catheter ablation of sustained VT in the setting of structural heart disease can only be considered an adjunctive therapy which, in general, will require ICD therapy. Numerous "modern" mapping technologies have been developed, which have increased success rates of catheter ablation of VT in patients with and without structural heart disease. The aim of the present article is to review current three-dimensional mapping systems in comparison to conventional mapping and to describe a reasonable, tailored approach for the individual patient with VT.

Management of late atrial tachyarrhythmia long after Fontan operation

The optimal management of atrial tachyarrhythmia (AT) late after Fontan operation has not yet been established. Of 199 patients who were followed for more than 10 years after Fontan operation, 60 patients in whom late postoperative arrhythmias were observed were the subjects of this study. These arrhythmias were managed with anti-arrhythmic drugs. Twenty-one of 60 patients (35%) did not respond to the drugs and they needed further interventions. Fourteen catheter ablation procedures were performed in nine patients (atrial fibrillation in one patient, AT in eight patients) and the success rate was 44%. Conversion to total cavopulmonary connection (TCPC) was performed in 14 patients and Maze operation was performed at the time of Fontan conversion in 6 patients. Sinus rhythm or pacemaker rhythm was maintained in 7 of 14 (50%) patients postoperatively. Although arrhythmogenic substrates accumulate and tachyarrhythmia becomes frequent over the long-term following Fontan operation, most patients with AT can be managed medically. The success rate of catheter ablation and Maze operation is low but those interventions may be indicated in patients with intractable arrhythmias.

How to assess the efficacy of catheter ablation of atrial fibrillation?

The reliability of rhythm monitoring in order to achieve consistent follow-up data in patients who underwent catheter ablation for atrial fibrillation (AF) is still not satisfying. Currently, Holter monitoring is widely used to evaluate the success rates after catheter ablation. Unfortunately, storage capacity of such ECG devices is limited and recording intervals cover only a small portion of the entire follow-up period. Very recently, new implantable loop-recorder devices have been introduced to validate catheter ablation success rates in those patients.1 Since all these devices lack the ability to obtain intracardiac electrograms, we sought to investigate the ‘real’ AF burden in our study using previously …

Efficacy and safety of radiofrequency catheter ablation in the elderly

Radiofrequency (RF) catheter ablation has not been widely undertaken in elderly patients. The aim of our study was to compare the success rate of radiofrequency ablation and the incidence of severe procedural complications in young-adult and elderly patients. We enrolled all patients undergoing radiofrequency catheter ablation procedures for supraventricular and ventricular arrhythmias at our Cardiology Department from January 2000 to December 2005. The patients were divided into two groups according to age: patients aged <70 years (group A) and those aged >or=70 years (group B). Group B was then divided into two subgroups: B1 (age 70-79 years) and B2 (age >or=80 years). We recorded the incidence of procedural complications and the long-term efficacy (mean follow-up 46 +/- 20 months). We studied 605 patients, 69% in group A and 31% in group B (24% in subgroup B1 and 7% in B2). The prevalence of structural heart disease was higher in elderly patients than in young adults (83 vs 37%, p < 0.01). The rate of procedural complications was 1.3%; no differences emerged between groups A and B (1.2 vs 1.5%, p = NS) or among groups A, B1 and B2 (1.2 vs 1.4 vs 2%, p = NS). The success rate of catheter ablation was 91%, with no differences between the age-groups (92 vs 88%, p = NS) or among groups A, B1 and B2 (92 vs 88 vs 88%, p = NS). Catheter ablation in elderly and very elderly patients is as effective and safe as in young-adult subjects, at least in cases which do not require left heart catheterization.

Anatomic Characteristics of the Left Atrial Isthmus in Patients with Atrial Fibrillation: Lessons from Computed Tomographic Images

Left atrial (LA) isthmus ablation was reported to improve the success rate of catheter ablation of paroxysmal atrial fibrillation (AF). LA isthmus ablation could also cure a subset of LA flutter. Therefore, understanding the anatomy of the LA isthmus is important for performing the ablation effectively. Group I included 45 patients (40 male, mean age = 50 +/- 13 years) with paroxysmal AF who underwent catheter ablation. Group II included 45 patients (37 male, mean age = 54 +/- 10 years) without a history of AF. They underwent a 16-slice multidetector computed tomography (MDCT) scan to delineate the LA structures before the ablation procedure. The average length of the LA isthmus was longer in group I than in group II (lateral isthmus: 3.30 +/- 0.68 vs 2.71 +/- 0.60 cm, P < 0.001; medial isthmus: 5.12 +/- 0.94 vs 4.45 +/- 0.63 cm, P < 0.001), and morphological patterns of lateral and medial isthmus were similar between groups. In addition, the average depth of lateral isthmus was similar between groups (0.62 +/- 0.32 vs 0.55 +/- 0.33 cm, P = 0.41), but the average depth of medial isthmus was larger in group I than in group II (0.60 +/- 0.32 vs 0.44 +/- 0.25 cm, P = 0.01). The medial isthmus had more ridges, as compared to the lateral isthmus (13% vs 0%, P = 0.026). Furthermore, the distances between esophagus and lateral isthmus were longer in group I than in group II (at the middle of isthmus and mitral annulus level: 21.0 +/- 4.8 vs 18.4 +/- 6.0 mm, P < 0.001; and 37.1 +/- 5.7 vs 29.6 +/- 8.1 mm, P < 0.001, respectively). The LA isthmus was longer in the AF patients. The morphology of the isthmus was variable. Compared with the lateral isthmus, the medial isthmus was longer and had more ridges. A peculiar configuration of the isthmus provided by CT images could influence the ablation strategy.

Success rate of catheter ablation in atrial flutter: Comparison of a 4- or 5-mm tip electrode catheter with an 8-mm tip electrode catheter

Radio frequency (RF) energy is capable of interrupting the reentrant circuit of atrial flutter and curing the arrhythmia. The development of 8-mm tip catheter provides more tissue damage and has offered the promise of improved success. The purpose of our study was to determine if the acute and long-term success with the 8-mm tips were superior to the 4- or 5-mm tips. The outcomes of the first 20 patients in whom an 8-mm tip catheter was used were compared with the previous 20 patients in whom a 4-or 5-mm tip catheter was used. Procedural (acute) ablation success was defined by creation of bi-directional isthmus block. Long-term success was defined as the prevention of clinically evident atrial flutter (AFl) as determined by the absence of symptoms or maintenance of sinus rhythm on electrocardiogram, six months to one year after the procedure. Compared to the 4- or 5-mm tip, the 8-mm catheter tip was associated with a reduced ablation duration {22.3 +/- 16 versus 11.5 +/- 5 min (p = 0.0078)}, a lower mean number of ablations {13.5 +/- 9.9 versus 6.8 +/- 2.9 (p = 0.0065)} and a reduced procedure time {1.8 +/- 0.7 versus 1.1 +/- 0.5 h (p = 0.0032)}. Acute success was 95% in the 4- or 5-mm group versus 80% in the 8-mm group (p = NS), but long-term success was higher in the 8-mm group than the 4- or 5-mm group (87.5 versus 63.2%, p = 0.0436). Eight-millimeter tip catheters for AFl shorten procedure time, reduce the duration and number of ablations and accomplish bi-directional block when compared with smaller tipped catheters. The long-term success rate is better with the 8-mm tips and should be the preferred catheter for RF ablation of AFl.

Long-term single procedure efficacy of catheter ablation of atrial fibrillation

Two important limitations of the data regarding the outcomes of catheter ablation of atrial fibrillation (AF) are the short-term follow-up used in most published studies and the lack of single-procedure outcomes. The objective was to report the long-term single-procedure outcomes at our center. The patient population was comprised of 200 consecutive patients who underwent ablation (133 men; age 56 +/- 11 years). Atrial fibrillation was paroxysmal in 92 (46%). Success was defined as absence of symptomatic AF, off antiarrhythmic drug (AAD) after a single procedure. After a follow-up of 26 +/- 11 months, the single-procedure long-term success rate was 28% with an additional 7% of patients demonstrating improvement. After including repeat procedures in 64 patients, the overall long-term success rate was 41% with 11% demonstrating improvement. Further subgroup analysis of 48 paroxysmal AF patients considered to be optimal candidates for the procedure, revealed a long-term success rate of 69% with an additional 4% demonstrating improvement. A major complication occurred in 7.9% of patients. The results reveal that the long-term single-procedure success rate of catheter ablation of AF in a cohort of patients with predominantly non-paroxysmal AF is less than 40%. The inclusion of redo procedures resulted in an improvement in outcomes. A much higher success rate of 69% was achieved in patients with paroxysmal AF considered to be optimal candidates for this procedure. These results make it clear that further advances in the technique of catheter ablation of AF are needed to improve the safety and efficacy of this procedure. In order to be able to compare outcomes of various techniques in differing patient populations, we urge investigators to report long-term single procedure outcomes.

P5-73: The important role of coronary sinus morphology in patients with atrial fibrillation: New insight from image study and catheter ablation

Coronary sinus (CS) musculature has been demonstrated to be involved in a variety of arrhythmias, including atrial fibrillation (AF). Catheter ablation at CS ostium (CSO) or within CS has been reported to improve the success rate of catheter ablation in patients with AF. However, the relationship between the success of AF ablation and morphology of coronary sinus in AF patients has not been reported.

When to Perform Catheter Ablation in Asymptomatic Patients With a Wolff-Parkinson-White Electrocardiogram

What to do when a person without any cardiac complaint shows a Wolff-Parkinson-White (WPW) pattern on the ECG has been an important question for more than 2 decades. Recent articles by Pappone et al1–3 make it necessary to revisit that question. Epidemiological data indicate that 0.1% to 0.3% of the general population have ECG findings suggesting that during sinus rhythm, in addition to AV conduction over the AV node His pathway, there is also AV conduction over an accessory AV pathway (AP).4 This means that each year ≈4 new cases are found in a population of 100 000. It is also known that there is a 4-fold increase of this finding in family members of WPW patients.5 The WPW patient is often symptomatic because of cardiac arrhythmias. When arrhythmias are present, the disorder is called the WPW syndrome. The 2 most common types of arrhythmia in the WPW syndrome are (1) a circus movement tachycardia (CMT), also called an AV reentrant tachycardia, in which AV conduction goes by way of the normal AV conduction system and VA conduction over the AP and (2) atrial fibrillation (AF).6 AF can be a life-threatening arrhythmia in the WPW syndrome if the AV AP has a short anterograde refractory period (RP), allowing many atrial impulses to be conducted to the ventricle. That will result in very high ventricular rates with possible deterioration into ventricular fibrillation (VF) and sudden death.7,8 A CMT that in general is well tolerated by the patient when additional heart disease is absent may deteriorate into AF, and the ventricular rate and risk for VF will depend on the anterograde RP of the AP. Therefore, the most important question in the asymptomatic WPW patient in whom the typical ECG accidentally is recorded is whether he or …

Noncontact mapping of ectopic atrial tachycardias: different characteristics of isopotential maps and unipolar electrogram.

The success rate for catheter ablation of ectopic atrial tachycardia (AT) has been limited by the inherent difficulty in localizing the site of origin within the complex three-dimensional structures of the atria. The objective of the study was to determine the usefulness of a noncontact mapping system for catheter ablation of AT. Radiofrequency ablation of 25 ATs was performed using a noncontact mapping system. Three different characteristics of isopotential maps and unipolar electrogram morphologies were observed: Group 1: Isopotential maps displayed a narrow, sharp ring of colors around a white, center spot. Unipolar electrograms revealed a Q-S morphology with a rapid dV/dt. Group 2: Isopotential maps displayed a broad ring of colors with little or no white spot in the center. Unipolar electrograms revealed a low amplitude, broad and smooth Q-S morphology in front of a second component with a rapid dV/dt. Group 3: Isopotential maps displayed a broad ring of colors. Unipolar electrogams revealed a low amplitude and fractionated waveform followed by endocardial breakthrough with a gradual dV/dt. Radiofrequency catheter ablation was successful in all ATs of groups 1 and 2, and failed in two of three ATs in group 3. The overall success rate was 92%. No severe complications were observed. Noncontact isopotential mapping is helpful to identify and characterize the origin of ectopic AT. Ablation success is associated with the characteristics of isopotential maps and unipolar electrogram morphologies. The overall success rate was 92%.

Radiofrequency catheter ablation of supraventricular tachycardia substrates after mustard and senning operations for d-transposition of the great arteries

OBJECTIVESThe purpose of this study was to determine the efficacy and risks of radiofrequency ablation of various forms of supraventricular tachycardia after Mustard and Senning operations for d-transposition of the great arteries.BACKGROUNDIn this patient group, the reported success rate of catheter ablation of intraatrial reentry tachycardia is about 70% with a negligible complication rate. There are no reports of the use of radiofrequency ablation to treat other types of supraventricular tachycardia.METHODSStandard diagnostic criteria were used to determine supraventricular tachycardia type. Appropriate sites for attempted ablation included 1) intraatrial reentry tachycardia: presence of concealed entrainment with a postpacing interval similar to tachycardia cycle length; 2) focal atrial tachycardia: a P-A interval ≤−20 ms; and 3) typical variety of atrioventricular (AV) node reentry tachycardia: combined electrographic and radiographic features.RESULTSNine Mustard and two Senning patients underwent 13 studies to successfully ablate all supraventricular tachycardia substrates in eight (73%) patients. Eight of eleven (73%) patients having intraatrial reentry tachycardia, 3/3 having typical AV node reentry tachycardia, and 2/2 having focal atrial reentry tachycardia were successfully ablated. Among five patients having intraatrial reentry tachycardia (IART) and not having ventriculoatrial (V-A) conduction, two suffered high-grade AV block when ablation of the systemic venous portion of the medial tricuspid valve/inferior vena cava isthmus was attempted.CONCLUSIONSRadiofrequency catheter ablation can be effectively and safely performed for certain supraventricular tachycardia types in addition to intraatrial reentry. A novel catheter course is required for slow pathway modification. High-grade AV block is a potential risk of lesions placed in the systemic venous medial isthmus.

The right ventricular tachycardias

A variety of tachycardias originate from the right ventricle or use right ventricular structures as part of their circuit. They are characterized by a left bundle branch block pattern. Many of these tachycardias are relatively easy targets for radiofrequency catheter ablation. Ventricular tachycardia (VT) is the most common manifestation of arrhythmogenic right ventricular dysplasia, an often familial disease that can cause sudden death. Catheter ablation, antiar-rhythmic drugs, or an implantable cardioverter-defibrillator may be used as therapy. Idiopathic right ventricular tachycardia has a benign course. It most often arises from the septal region of the right ventricular outflow tract. It commonly presents as nonsustained, repetitive monomorphic VT. The success rate of catheter ablation is greater than 90%. Bundle branch reentry occurs in patients with cardiomyopathy and His-Purkinje disease. It uses the right bundle branch anterogradely and the left bundle branch retrogradely. The QRS is very similar during VT and sinus rhythm. It can be cured by catheter ablation of the right bundle branch. VT seldom originates from the right ventricle in patients with coronary artery disease, idiopathic cardiomyopathy, or myocarditis. Atriofascicular (so-called Mahaim) fibers can sustain antidromic AV reentrant tachycardia. They represent an accessory AV node and His-Purkinje-like conduction system with atrial insertion in the right free wall near the tricuspid annulus and distal insertion directly into the right bundle branch. The accessory connection is ablated at the level of the tricuspid ring.

Laser catheter coagulation of normal and scarred ventricular myocardium in dogs.

Larger lesions would increase success rates of catheter ablation of ventricular arrhythmias. Therefore, improved radio frequency current application techniques, but also alternative energy sources, are being investigated. The purpose of this study was to determine morphology and dimensions of ventricular lesions induced by transcatheter application of laser energy. A total of 244 lesions were produced by Nd:YAG laser pulses, 1,064 nm, 10-30 W, 15-60 s, percutaneously (endocardial approach, n = 124) and under visual control (epicardial approach, n = 120) in the left ventricular walls of 24 anesthetized dogs. Dimensions of lesions increased with the amount of energy applied. Maximal values were obtained at 20 W, 60 s: depth = 12.6 +/- 1.1 mm (transmural); width = 15.0 +/- 2.8 mm; volume = 1,582 +/- 777 mm3. Volumes of lesions did not change significantly when induced through previously scarred myocardium. Histologically, lesions were clear-cut, without crater or thrombus formation. Procedures and follow-up periods of up to 22 months were without complications. Nd:YAG laser pulses at 10-20 W and 15-60 s produce homogeneous myocardial lesions of coagulation necrosis of reproducible sizes, in a controllable manner, without unwanted effects on the ventricular walls, in normal and through scarred myocardium of dogs. The laser method is a promising alternative for ablation of ventricular arrhythmias including candidates with ischemic heart disease.

Non-pharmacological treatment of supraventricular arrhythmias.

In recent years the recognition of toxicity and relative ineffectiveness of antiarrhythmic drugs in the management of arrhythmias has led to the development of non-pharmacological approaches. In the setting of supraventricular arrhythmias, such non-pharmacological approaches include preventative pacing, atrial defibrillation, surgery and radiofrequency catheter ablation. Success rates for catheter ablation exceeding 90% are expected in A-V nodal reentrant tachycardia. A-V reentry due to concealed or manifest bypass tracts, and incessant atrial tachycardias. Success rates in the management of atrial flutter are rapidly approaching this. Atrial fibrillation remains the main problem for which pharmacological therapy may still be useful. New preventative pacing modes, automatic atrial defibrillation, and perhaps surgical or radiofrequency procedures to limit the ability to sustain atrial fibrillation are on the horizon.

Why Is Catheter Ablation Less Successful than Surgery for Treating Ventricular Tachycardia that Results from Coronary Artery Disease?

Nearly 80% of patients with coronary artery disease who have map-directed surgery for control of ventricular tachycardias require no drug therapy to prevent recurrences, while fewer than 50% of patients undergoing catheter ablation have similar outcomes. Catheter ablation will fail if arrhythmogenic sites are incompletely ablated by lesions that are too small or too far away from the reentrant pathway or if all arrhythmogenic sites are not identified. The underlying assumptions used to guide site selection are that: (a) ventricular tachycardias arise from reentrant mechanisms; (b) monomorphic ventricular tachycardias with similar QRS morphologies arise from the same pathway; (c) the ventricular tachycardia initiated during the procedure represents the patient's spontaneous arrhythmia; (d) the endocardial site that should be ablated can be identified from cardiac activation maps produced during induced ventricular tachycardia or from ancillary techniques; and (e) the patient has only one or two reentrant pathways. Relying on incorrect assumptions may account for the difference in success rates. Patients may have similar appearing ventricular tachycardias that arise from different pathways, and the entire thin layer of viable tissue between the infarct and the endocardium may contain many reentrant pathways. Some ventricular tachycardias may arise from the myocardium away from the endocardium, while others may arise from the epicardium. Small lesions may not be large enough to eliminate all possible reentrant pathways. Catheter ablation may be less successful because the lesions are inadequate, the assumptions guiding the selection of arrhythmogenic tissue are incorrect, or all arrhythmogenic sites are not identified. The primary reason catheter ablation is less successful than surgery in the treatment of ventricular tachycardias is that catheter ablation does not ablate as much tissue as is removed by surgery. The success rate of catheter ablation probably can be improved if the amount of tissue ablated is increased.

Catheter ablation of ventricular tachycardia

The role and success rate of catheter ablation for monomorphic ventricular tachycardia (VT) depend on the mechanism and origin of the tachycardia (i.e., myocardial versus His-Purkinje system) and whether it occurs in the presence or absence of structural heart disease. For sustained bundle-branch reentry, a form of VT associated with structural heart disease, radiofrequency catheter ablation of the right bundle-branch can be performed readily and is highly successful in eliminating this arrhythmia. Because of modest success rates of catheter ablation of VT associated with a prior infarction (between 17% and 75%), this treatment modality is usually considered for cases refractory to drug therapy and should be viewed as adjunctive therapy. The target for ablation is a critical area of slow conduction, which is selected based on earliest endocardial activation, mid-diastolic potentials, concealed entrainment, or pace mapping. Radiofrequency catheter ablation may be the treatment of choice in patients with VT and no apparent structural heart disease; this is especially true for young patients who would otherwise require long-life antiarrhythmic therapy. Success rates between 75% and 100% have been reported, especially when the origin is in the right ventricular outflow tract.