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Biomedical subjects

J M Kalman

Publications and source records attributed to J M Kalman.

53 records · Page 3Linked to original sources
PubMed1995

Radiofrequency catheter modification of the sinus node for "inappropriate" sinus tachycardia.

BACKGROUND: Radiofrequency catheter ablation is the treatment of choice for patients with paroxysmal supraventricular tachycardias refractory to medical therapy. However, in symptomatic patients with inappropriate sinus tachycardia resistant to drug therapy, catheter ablation of the His' bundle with permanent pacemaker insertion is currently applied. We evaluated the safety and efficacy of radiofrequency modification of the sinus node as alternative therapy for patients with inappropriate sinus tachycardia. METHODS AND RESULTS: Sixteen patients with disabling episodes of inappropriate sinus tachycardia refractory to drug therapy (4.2 +/- 0.3 drug trials) underwent either total sinus node ablation or sinus node modification. The region of the sinus node was identified as the region of earliest atrial activation in sinus rhythm during electrophysiological study. This region was further defined by use of intracardiac echocardiography (ICE) in 9 patients, in whom it was found that an ablation catheter could be guided reliably and maintained on the crista terminalis. Radiofrequency energy was delivered during tachycardia between either a standard 4-mm or custom 10-mm thermistor-imbedded catheter tip and a skin patch. Total sinus node ablation was performed successfully in all 4 patients in whom it was attempted and was characterized by a junctional escape rhythm. Sinus node modification was successfully achieved in all 12 patients in whom it was attempted and was characterized by a 25% reduction in the sinus heart rate. For the group as a whole, exercise stress testing after ablation revealed a gradual chronotropic response, with a significant reduction in maximal heart rate (132.8 +/- 6.5 versus 179.5 +/- 3.6 beats per minute [bpm]; P < .001) without evidence of an exaggerated heart rate response to a light workload (103.0 +/- 4.1 versus 139.5 +/- 3.5 bpm; P < .001). Twenty-four-hour ambulatory ECG monitoring revealed a significant decrease in maximal heart rate and mean heart rate after ablation (167.2 +/- 2.6 versus 96.7 +/- 5.0 bpm, P < .001, and 125.6 +/- 5.0 versus 54.1 +/- 5.3 bpm, P < .001, respectively). There was a significant decrease in the number of applications of radiofrequency energy required in patients undergoing modification of the sinus node when guided by ICE compared with fluoroscopy alone (3.6 +/- 0.8 versus 10.4 +/- 2.1; P < .01) as well as a decrease in fluoroscopy time (33.0 +/- 9.5 versus 58.5 +/- 8.4 minutes). After a mean follow-up period of 20.5 +/- 0.3 months, there were no recurrences of inappropriate sinus tachycardia in patients who underwent a total sinus node ablation. However, 2 patients who had a total sinus node ablation subsequently required permanent pacing because of symptomatic pauses, and 1 patient developed an ectopic atrial tachycardia. After a mean follow-up of 7.1 +/- 1.7 months, there were two recurrences of inappropriate sinus tachycardia in patients who underwent sinus node modification. However, no significant bradycardia or pauses were observed. Complications encountered during the study included 1 patient who developed transient right diaphragmatic paralysis and another patient who developed transient superior vena cava syndrome. CONCLUSIONS: Sinus node modification is feasible in humans and should be considered as an alternative to complete atrioventricular junctional ablation for patients with disabling inappropriate sinus tachycardia refractory to medical management. Sinus node modification may be aided by ICE.

Adult↗
PubMed1995

Radiofrequency catheter modification of sinus pacemaker function guided by intracardiac echocardiography.

BACKGROUND: The sinus P wave arises from a pacemaker complex distributed along the crista terminalis. We investigated the feasibility of modification of sinus pacemaker function using graded applications of radiofrequency energy along the crista terminalis in dogs to achieve sinus rate control. METHODS AND RESULTS: Modification of sinus pacemaker function (30 +/- 5% reduction in intrinsic heart rate with retention of a normal P-wave axis) was performed in 11 dogs (group 1). Total sinus pacemaker ablation (> 50% reduction in intrinsic heart rate with development of a low ectopic atrial or a junctional rhythm) was performed in 4 dogs (group 2). Intracardiac echocardiography was used to identify the crista terminalis as an anatomic marker of sinus node location. Sinus pacemaker modification caused a significant decrease in intrinsic heart rate (31% reduction, P < .001), heart rate responsiveness to isoproterenol (30% reduction, P < .0001), and average (20% reduction, P = .0002) and maximal (22% reduction, P = .0007) heart rates during 24-hour Holter monitoring. In 6 of the 11 animals, the targeted rate reduction of 30 +/- 5% was accurately achieved (mean, 31.6 +/- 4.3%; P < .001), and in the other 5, significant reduction of intrinsic heart rate was achieved but with greater variation (28.0 +/- 17.3%, P < .005). Corrected sinus node recovery time was not prolonged. After modification, earliest activation was mapped to the crista terminalis inferior to the lesion in all animals. In long-term follow-up (3.7 +/- 1.0 months), effects were maintained. After total sinus pacemaker ablation, junctional and low atrial escape pacemakers were unstable. CONCLUSIONS: This study demonstrates the feasibility of modification of sinus pacemaker function for sinus rate control using catheter-based radiofrequency ablation guided by intracardiac echocardiography. This can be done while pacemaker stability and attenuated responsiveness to autonomic influences are preserved. Intracardiac echocardiography accurately defined the crista terminalis and provided a reliable means to anatomically localize catheter position in relation to the sinus node.

Animals↗
PubMed1995

Role of right atrial endocardial structures as barriers to conduction during human type I atrial flutter. Activation and entrainment mapping guided by intracardiac echocardiography.

BACKGROUND: The importance of barriers in atrial flutter has been demonstrated in animals. We used activation and entrainment mapping, guided by intracardiac echocardiography (ICE), to determine whether the crista terminalis (CT) and eustachian ridge (ER) are barriers to conduction during typical atrial flutter in humans. METHODS AND RESULTS: In eight patients, ICE was used to guide the placement of 20-pole and octapolar catheters along the CT and interatrial septum and a roving catheter to nine sites: just posterior (1) and anterior (2) to the CT along the lateral right atrium, at the fossa ovalis (3), and just posterior and anterior to the ER at the low posterolateral (4 and 5), low posterior (6 and 7), and low posteromedial (8 and 9) right atrium. Entrainment was performed, and each site was considered within the flutter circuit if the postpacing interval-flutter cycle length (PPI-FCL) and the stimulus time-activation time (stim time-act time) were < 10 msec. Split potentials were recorded along the CT with components activated in a low-to-high pattern and a high-to-low pattern. Conduction times, as percentage of FCL, were significantly different at sites on either side of the CT and ER: site 1 (33 +/- 13%) and site 2 (43 +/- 12%) (P = .02), site 4 (48 +/- 24%) and site 5 (75 +/- 8.9%) (P = .02), and site 6 (22 +/- 10%) and site 7 (82 +/- 5.3%) (P = .0009). During entrainment, no surface fusion was observed at sites 5, 7, or 9. The PPI-FCL and stim time-act time were not significantly different than 0 at sites 2, 7, 5, or 9, indicating that they were within the flutter circuit, whereas sites 1, 3, 4, and 6 were not. CONCLUSIONS: ICE enabled the correlation of functional electrophysiological properties with specific anatomic landmarks, identifying the CT and ER as barriers to conduction during human atrial flutter.

Aged↗
PubMed1995

Atrial fibrillation after coronary artery bypass grafting is associated with sympathetic activation.

BACKGROUND: We prospectively investigated the role of sympathetic activation in the etiology of atrial fibrillation following coronary artery bypass grafting. METHODS: Continuous ambulatory monitoring was performed for 80 hours in 131 patients after coronary artery bypass grafting. Right atrial plasma norepinephrine levels were assessed preoperatively and every 4 hours for 48 hours postoperatively. RESULTS: Of the 131 patients, 50% (65) had development of atrial fibrillation and 36% (47) required treatment. Onset of atrial fibrillation was preceded by a significant increase in sinus rate and atrial ectopic activity. On multivariate logistic regression, elevated mean postoperative norepinephrine levels (5.78 +/- 2.83 versus 3.57 +/- 1.31 nmol/L; p < 0.0001), increased age (68.9 +/- 5.7 versus 63.8 +/- 8.7 years; p = 0.02), and decreased postoperative magnesium levels (0.79 +/- 0.09 versus 0.83 +/- 0.10 mmol/L; p = 0.02) were independently associated with the occurrence of atrial fibrillation. CONCLUSIONS: Elevated norepinephrine levels suggest that sympathetic activation may be important in the pathogenesis of atrial fibrillation after coronary artery bypass grafting, and this underlines the importance of beta-adrenoceptor blockade as prophylaxis.

Aged↗
PubMed1995

Low energy endocardial cardioversion of atrial arrhythmias in humans.

We assessed the feasibility of low energy endocardial defibrillation in patients with atrial fibrillation or atrial flutter who had failed a trial of pharmacological reversion with amiodarone. Low energy endocardial defibrillation under general anesthesia was attempted in 9 patients, 5 with atrial flutter and 4 with atrial fibrillation (median duration of arrhythmia 3.75 months). Two large surface area endocardial leads were introduced percutaneously and sited in the right atrial appendage and at the right ventricular apex. A cutaneous patch electrode was placed on the left thorax. Biphasic shocks synchronized to the ventricular electrogram were used to terminate atrial arrhythmias. Three electrode configurations were evaluated in the following sequence at each energy level: atrial cathode to ventricular anode; ventricular cathode to atrial anode; atrial cathode to a combined ventricular and cutaneous anode. If endocardial defibrillation failed (0.5-10 J), transthoracic defibrillation using 200 joules followed by 360 joules, if required, was performed. Endocardial defibrillation was successful in all five patients with atrial flutter (0.5 J, 1.0 J, 1.0 J, 4.0 J, and 10.0 J) but in only one patient with atrial fibrillation (10 J). On no occasion did successful defibrillation occur with one configuration when it had failed with an alternate configuration at that particular energy level. Ventricular fibrillation did not occur, and there were no other significant complications. Low energy endocardial defibrillation is feasible in patients with atrial flutter using large surface area electrodes. Although the success rate of atrial defibrillation was low, further work is required, particularly in patients with more recent onset of the arrhythmia and using a right to left electrode configuration.

Adult↗
PubMed1995

Specific effects of zatebradine on sinus node function: suppression of automaticity, prolongation of sinoatrial conduction and pacemaker shift in the denervated canine heart.

We evaluated the cardiac electrophysiological effects of zatebradine in eight anesthetized and autonomically denervated canines, with particular emphasis on the effects on sinus node automaticity and sinoatrial conduction (SACT), both at rest and after atrial overdrive pacing. Sinus node function was assessed by using the recorded sinus node electrogram and also by applying a previously validated mathematical model of sinus node function which allows separate evaluation of effects of pacing on SACT and suppression of automaticity. Other standard electrophysiological parameters also were measured. Tests were performed before and after incremental doses of zatebradine (0.0625, 0.125 and 0.25 mg/kg). Zatebradine caused a significant, dose-related increase in cardiac cycle length. There also was a significant, dose-related increase in both suppression of automaticity and SACT (independent of changes in cycle length) after zatebradine. The only other significant electrophysiological effect was a relatively minor increase in the ventricular effective refractory period (13%). Higher doses of zatebradine were associated with spontaneous pacemaker shift characterized by loss of the sinus node electrogram and variation in P-wave morphology. Our results confirm that the effects of zatebradine are relatively specific for the sinus node. These included: 1) prolongation of resting sinus cycle length; 2) enhanced suppression of automaticity after overdrive pacing; 3) prolongation of SACT; and 4) induction of sinus node pacemaker shifts. This agent should be used cautiously in patients with possible sinus node dysfunction.

Animals↗
PubMed1995

Proximal aortic atheroma. An independent risk factor for cerebral ischemia.

BACKGROUND AND PURPOSE: Transesophageal echocardiography frequently demonstrates aortic atheroma in patients with cerebral and peripheral emboli. The aim of this study was to determine whether atheroma in the ascending aorta and arch is an independent risk factor for cerebral ischemia. METHODS: We studied 215 consecutive patients with a first stroke or transient ischemic attack and 202 community-based control subjects using transesophageal echocardiography to detect aortic atheroma and potential cardiac sources for embolism. Information about other stroke risk factors was obtained from a structured interview, and the presence of carotid vascular disease was assessed by means of duplex ultrasonography or digital subtraction angiography. Multiple logistic regression analysis was used to determine adjusted odds ratios for each risk factor. RESULTS: Atheroma in the ascending aorta and aortic arch was a significant risk factor for cerebral ischemia, independent of other well-established risk factors including high-grade carotid stenosis. The odds ratio for simple atheroma was 2.3 (95% confidence interval, 1.2 to 4.2) and for complex atheroma 7.1 (2.7 to 18.4). CONCLUSIONS: Ascending aortic and arch atheroma detected by transesophageal echocardiography is an important new independent risk factor for cerebral ischemia. Further characterization of the embolic potential of atheroma with different echocardiographic appearances and development of optimal management strategies are now needed.

Adult↗
PubMed1994

Intracardiac echocardiography during radiofrequency catheter ablation of cardiac arrhythmias in humans.

OBJECTIVES: The purpose of this study was to describe our preliminary experience using catheter-based intracardiac echocardiography as an adjunct to biplane fluoroscopy for guiding radiofrequency catheter ablation of atrial arrhythmias in the right side of the heart. BACKGROUND: Catheter ablation requires precise positioning and stable ablation electrode-endocardial contact. This procedure is currently guided by an analysis of intracardiac electrograms and fluoroscopy. However, the use of fluoroscopy does not allow the endocardium and certain anatomic landmarks to be identified and is associated with the hazards of radiation exposure. METHODS: Seventeen symptomatic patients were studied. A 10F 10-MHz intracardiac imaging catheter was used to visualize specific anatomic landmarks in the right atrium for directing the ablation electrode in 15 patients undergoing radiofrequency ablation of 19 arrhythmias and to assist with interatrial septal puncture in 3 patients. RESULTS: Continuous intracardiac imaging was performed for a mean +/- SD of 63.6 +/- 39.2 min and demonstrated distal electrode-endocardial tissue contact in 81 (60%) of 134 radiofrequency applications. Movement of the catheter was demonstrated during 36 (44%), microcavitations during 39 (48%) and thrombus during 15 (19%) of the 81 imaged applications. In 7 of 10 procedures for atrial flutter, successful ablation was directed at anatomic corridors in the right atrium visualized with intracardiac echocardiography. During ablation of atrial tachycardia, imaging identified abnormal atrial anatomy related to previous surgery and guided successful ablation of a reentrant tachycardia circulating around these anatomic obstacles. In two procedures for slow pathway modification of atrioventricular node reentrant tachycardia, intracardiac echocardiography confirmed catheter stability at the tricuspid annulus anterior to the coronary sinus. CONCLUSIONS: During catheter ablation, intracardiac echocardiography augments fluoroscopy by visualizing anatomic landmarks, ensuring stable endocardial contact and assisting in transseptal puncture. Ablation of typical atrial flutter can be successfully directed at anatomic corridors identified using intracardiac imaging.

Atrial Flutter↗
PubMed1994

A mathematical model of sinus node function: validation by recording of sinus node electrograms.

We have applied a mathematical function to model sinus node recovery after atrial pacing at different cycle lengths in 13 autonomically denervated, anesthetized canines. This model provides "pure" indexes of sinoatrial conduction and of suppression of automaticity. We compared sinoatrial conduction computed from the model (SACTc) with sinoatrial conduction measured directly utilizing a catheter recording the sinus node electrogram (SACTd) to test the validity of the model. We used both the model and the sinus node electrogram to further define events after pacing. There was close agreement between SACTc and SACTd with correlation coefficients at pacing cycle lengths of 20 and 50% below resting of 0.86 (P < 0.0001) and 0.78 (P < 0.0001), respectively. We verified that the conventional sinus node recovery time is due both to suppression of automaticity and prolongation of sinoatrial conduction. Sinoatrial conduction time returned rapidly to normal over 1-3 beats, whereas automaticity recovered exponentially over 20-40 postpacing intervals. The model accurately describes postpacing phenomena and has the potential to provide a useful adjunct to the measurement of the sinus node electrogram for assessment of sinus node function in the experimental laboratory.

Animals↗
PubMed1993

Importance of electrode design, lead configuration and impedance for successful low energy transcatheter atrial defibrillation in dogs.

OBJECTIVES: We assessed the feasibility of low energy endocardial defibrillation in a canine model of atrial fibrillation, comparing catheters with large surface area electrodes and standard electrode catheters, and evaluated the effects of lead configuration and circuit impedance on defibrillation energy requirements. BACKGROUND: Although recent animal studies have demonstrated the feasibility of low energy endocardial atrial defibrillation, their results have been conflicting with regard to important methodologic aspects. METHODS: In 14 anesthetized greyhounds, atrial fibrillation was induced by rapid atrial pacing and maintained by vagal stimulation. Two large surface area braided electrode catheters and two standard electrode catheters were introduced percutaneously, one of each, in the right atrial appendage and right ventricular apex. A cutaneous patch electrode was placed on the left thorax. Biphasic shocks synchronized to the ventricular electrogram were used to terminate atrial fibrillation. Seven configurations were evaluated. Three used standard electrodes: proximal atrial cathode to distal atrial, ventricular or cutaneous anode. Four used braided electrodes: three with atrial cathode to ventricular, cutaneous or combined anode; one with ventricular cathode to atrial anode. RESULTS: Defibrillation with standard electrode catheters was associated with high impedance (576 +/- 112 omega) and low success rates for all configurations (28% success at < or = 40 J, no successes at 10 J). Low energy defibrillation was readily achieved with the braided electrodes with significantly lower impedance (75 +/- 13 omega, p < 0.0001). Ventricular fibrillation did not occur. The success rate of cardioversion increased in a dose-response manner, allowing fitting of a sigmoid curve and calculation of energy associated with 50% (ED50) and 90% (ED90) success. The most successful configuration was ventricular cathode/atrial anode (ED50 1.5 +/- 0.4 J), and the least successful was atrial anode/cutaneous patch (ED50 6.5 +/- 3.2 J, p = 0.0001). CONCLUSIONS: Low energy atrial defibrillation is feasible using large surface area electrodes but not with standard electrode catheters owing to high impedance. An intracardiac anode provides lower impedance and higher success rates than are provided by a cutaneous anode.

Analysis of Variance↗
PubMed1993

Cost effectiveness of radiofrequency catheter ablation in the treatment of symptomatic supraventricular tachyarrhythmias.

BACKGROUND: The recent advent of radiofrequency (RF) catheter ablation as a curative therapy for supraventricular tachyarrhythmias has challenged the role of long term drug treatment, which is essentially a palliative therapy. To date, however, no data have been published on the cost-effectiveness of RF ablation as compared with drug treatment in the Australian setting. AIMS: The study aimed to compare actual and projected costs of these two treatment options in a consecutive group of patients having RF ablation as treatment for symptomatic tachyarrhythmias. METHODS: The cost effectiveness of RF catheter ablation was assessed in 26 patients having RF ablation, using a hypothetical model of continued drug therapy in the same group of patients. A 'cost saving' criterion was used for cost effectiveness. Actual costs for the RF ablation and for continued drug therapy were based on data from medical records and from the answers to a detailed patient questionnaire. Analysis included costs of prior diagnostic electrophysiology (EP) study (17/26 patients), general anaesthesia (GA: 20/26 patients), post-ablation echocardiography (10/26 patients), and late follow-up EP study (7/26 patients). The in-hospital stay for the RF ablation was two days in all cases, and no patient required implantation of a permanent pacemaker. The RF ablation procedure was successful in 23/26 patients (88.5%) with late recurrence of tachycardia in one patient. After a median follow-up of nine months, 22/26 patients no longer require antiarrhythmic drug therapy. RESULTS: The mean per patient cost of RF ablation was $4067 in the study group. This reduces to $2546 if prior EP study and GA are excluded. The mean per patient cost of continued medical therapy was $700 per year. Extrapolating over 20 years and allowing for an annual 5% inflation factor, RF ablation becomes cost saving in 5.5 years (3.8 years if prior EP and GA are excluded). Over 20 years, continued drug therapy would be four to five times more expensive than RF ablation in the patient study group. We consider RF ablation to be a cost-effective alternative to long term drug therapy in patients with supraventricular tachyarrhythmias.

Adolescent↗
PubMed1993

Evaluation of mitral valve repair by intraoperative transoesophageal echocardiography.

BACKGROUND: Mitral valve repair is the procedure of choice in the surgical management of mitral regurgitation. Intraoperative confirmation of successful repair is essential to the effectiveness of this procedure. AIMS: The aims of this study were: (a) to compare intraoperative transoesophageal echocardiography (TOE) with the surgeon's assessment of valve competence; (b) to assess the impact of routine intraoperative imaging on the hospital echocardiography laboratory. METHODS: Eighty-six consecutive patients undergoing mitral valve repair formed the study population. Valve competence following repair was assessed intraoperatively by: TOE; saline insufflation of the flaccid left ventricle; and evaluation of the pulmonary capillary wedge pressure for the presence of a significant V wave. RESULTS: TOE demonstrated successful valve repair (< or = 1 + residual regurgitation) in 75 patients (87%) and detected significant residual regurgitation (> or = 3+) in seven (8.2%). The mechanism of regurgitation was also clearly shown. Of these seven patients, four underwent immediate valve replacement, two had successful revision of the initial repair and one required valve replacement one week later. In all seven patients the valve repair had been assessed as successful by saline testing and only one had a post-repair V wave 10 mmHg above the mean pulmonary capillary wedge pressure. In 30 non-selected patients the imaging equipment was required in theatre for 43 +/- 18 minutes. CONCLUSIONS: TOE is currently the most sensitive method for detection and quantitation of residual mitral regurgitation following valve repair. Evaluation can be performed within a similar time to that required for one complete transthoracic study and can usually be performed with minimal disruption to the hospital echocardiography laboratory.

Echocardiography, Transesophageal↗
PubMed1992

Atrial fibrillation: epidemiology and the risk and prevention of stroke.

Atrial fibrillation is a common disorder and the incidence increases with each decade of life. Previously, rheumatic mitral valve disease has been the condition most highly associated with atrial fibrillation. However, with the decreasing incidence of rheumatic heart disease, other conditions have assumed greater importance and now congestive cardiac failure, coronary artery disease, and hypertension are the most commonly associated conditions. Nonrheumatic atrial fibrillation is associated with an approximately five-fold increase in the risk of ischemic stroke and a 5% to 7% yearly risk that increases with age. In addition, atrial fibrillation is associated with an increased incidence of silent cerebral infarction and increased mortality. However, whether atrial fibrillation is independently associated with the risk of stroke or is a marker of underlying cardiac disease is contentious. Until recently, the use of preventive therapy has been controversial. However, data from four recently published, prospective randomized studies clearly support the use of warfarin prophylaxis in nonrheumatic atrial fibrillation. Within the diverse group of patients with nonrheumatic atrial fibrillation there are high and low risk subgroups and identification of these may influence decisions regarding antithrombotic prophylaxis. With a few exceptions, however, this remains an area in which there are contradictory findings in the literature. The role of aspirin for prophylaxis in nonrheumatic atrial fibrillation remains unclear and further evaluation awaits the publication of ongoing studies.

Atrial Fibrillation↗
PubMed1991

Multiple cardiac papillary fibroelastomas and rheumatic heart disease.

A case of severe rheumatic mitral stenosis was found to have multiple echodense masses attached to the ventricular surface of the mitral valve and papillary muscle at preoperative 2-dimensional echocardiography. Subsequent surgery involved mitral valve replacement and excision of the masses. Complete excision was confirmed by intraoperative transoesophageal echocardiography. Histologic examination of the surgical specimens showed typical papillary fibroelastomas. This is the first case report of multiple papillary fibroelastomas in association with rheumatic valvular disease demonstrated by 2-dimensional echocardiography.

Female↗
PubMed1990

Atrial fibrillation: the questions and controversies.

Atrial fibrillation is one of the commonest arrhythmias. It was first recognized over 100 years ago. However, many aspects including its mechanism, the role of autonomic as well as structural influences, and appropriate management including prevention of embolic events and indications for cardioversion have continued to provide questions for clinicians. This article is not intended to be all-embracing but to deal with some of these more perplexing and controversial areas.

Atrial Fibrillation↗
PubMedDate not supplied

Immediate and long-term results of radiofrequency ablation of pulmonary vein ectopy for cure of paroxysmal atrial fibrillation using a focal approach.

BACKGROUND: Atrial fibrillation (AF) is frequently initiated by focal activity originating in the pulmonary veins. We present the early and long-term results of a focal approach to pulmonary-vein ablation for cure of paroxysmal AF. AIMS: The aim of this study was to establish the effectiveness of focal pulmonary vein radiofrequency ablation (RFA) for cure of paroxysmal AF. METHODS: Fifty-one consecutive patients (35 male; 45+/-11.4 years) were considered for RFA on the following criteria: (i) symptomatic drug refractory AF, (ii) high-density atrial ectopy, bursts of atrial tachycardia or AF, (iii) absence of structural heart disease and (iv) provision of informed consent. Pulmonary vein mapping and RFA were by single trans-septal puncture, which was only performed in patients with adequate focal activity at the time of procedure. Focal activity was present spontaneously or was elicited by isoprenaline, burst pacing or AF induction and cardioversion. RESULTS: One patient was excluded from the analysis due to non-pulmonary vein triggers. Trans-septal mapping and RFA were not performed in 22 patients (44%) due to: (i) inadequate ectopy (17), (ii) recurrent AF (1), (iii) inability to cross septum (2) and (iv) multiple foci (2). Of 28 patients, RFA was attempted with procedural success in 23 patients (82%), with no acute complications. Mean fluoroscopy time for patients having RFA was 29+/-11.5 mins. Pulmonary vein stenosis occurred in one case. Ten patients had symptomatic recurrence and, of those, two had further RFA. At a mean follow up of 11+/-8 months, 15 patients (54% ablated, 30% of the total cohort) remained free of AF without antiarrhythmics. CONCLUSION: This series highlights the low long-term success rate of RFA to cure AF by targeting pulmonary vein initiators using a focal approach. Electrical pulmonary vein isolation may provide better long-term results.

Atrial Fibrillation↗