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Biomedical subjects

Aman Chugh

Publications and source records attributed to Aman Chugh.

At least 55 records · Page 3Linked to original sources
PubMed2004

Incremental value of isolating the right inferior pulmonary vein during pulmonary vein isolation procedures in patients with paroxysmal atrial fibrillation.

Electrical isolation of the left superior, left inferior, and right superior pulmonary veins (PVs) is often, but not always, effective in eliminating paroxysmal atrial fibrillation (PAF). The incremental clinical value of also isolating the right inferior PV has not been well defined. PV isolation by ostial applications of radiofrequency energy guided by PV potentials was performed in 176 consecutive patients (mean age 52 +/- 11 years) with PAF. The left superior, left inferior, and right superior PVs were targeted in 106 patients, and all four PVs were targeted 70 patients. Successful isolation was achieved in 96% of targeted PVs. The mean duration of follow-up was 15 +/- 7 months. At 1-year follow-up, 58% of patients in whom three PVs were isolated were free of recurrent PAF in the absence of antiarrhythmic drug therapy, compared to 73% of patients in whom all four PVs were isolated (P = 0.07). There is a trend towards a better outcome when all four PVs are isolated than when only the three major PVs are isolated. Whenever feasible, the right inferior PV should be isolated along with the other three PVs during the first ablation procedure in patients with PAF.

Adult↗
PubMed2003

Catheter ablation for paroxysmal atrial fibrillation: segmental pulmonary vein ostial ablation versus left atrial ablation.

BACKGROUND: Segmental ostial catheter ablation (SOCA) to isolate the pulmonary veins (PVs) and left atrial catheter ablation (LACA) to encircle the PVs both may eliminate paroxysmal atrial fibrillation (PAF). The relative efficacy of these 2 techniques has not been directly compared. METHODS AND RESULTS: Of 80 consecutive patients with symptomatic PAF (age, 52+/-10 years), 40 patients underwent PV isolation by SOCA and 40 patients underwent LACA to encircle the PVs. During SOCA, ostial PV potentials recorded with a ring catheter were targeted. LACA was performed by encircling the left- and right-sided PVs 1 to 2 cm from the ostia and was guided by an electroanatomic mapping system; ablation lines also were created in the mitral isthmus and posterior left atrium. The mean procedure and fluoroscopy times were 156+/-45 and 50+/-17 minutes for SOCA and 149+/-33 and 39+/-12 minutes for LACA, respectively. At 6 months, 67% of patients who underwent SOCA and 88% of patients who underwent LACA were free of symptomatic PAF when not taking antiarrhythmic drug therapy (P=0.02). Among the variables of age, sex, duration and frequency of PAF, ejection fraction, left atrial size, structural heart disease, and the ablation technique, only an increased left atrial size and the SOCA technique were independent predictors of recurrent PAF. The only complication was left atrial flutter in a patient who underwent LACA. CONCLUSIONS: In patients undergoing catheter ablation for PAF, LACA to encircle the PVs is more effective than SOCA.

Atrial Fibrillation↗
PubMed2003

Effects of operator experience on the outcome and duration of pulmonary vein isolation procedures for atrial fibrillation.

Segmental, ostial ablation to isolate the pulmonary veins has been shown to be effective for the treatment of atrial fibrillation (AF). The purpose of this study was to determine the effects of operator experience on the outcome and duration of pulmonary vein isolation procedures for AF. One hundred three consecutive patients with AF underwent segmental, ostial ablation to isolate pulmonary veins. The effect of operator experience on the outcome and duration of the procedure was measured. The mean procedure duration was 232 +/- 70 minutes (range 50 to 460). There was an indirect linear relation between the total procedure time and the number of procedures performed (r = -0.68; p <0.001), and between the total fluoroscopic time and the number of procedures performed (r = -0.71; p <0.001). The percentage of patients in whom complete isolation of the pulmonary veins was achieved and the total duration of radiofrequency energy delivered during the procedures remained stable as operator experience increased. Operator experience was not an independent predictor of recurrent AF. The primary effect of operator experience on pulmonary vein isolation procedures for AF was a marked reduction in the duration of the procedure and fluoroscopic time. Long procedure durations and large amounts of radiation exposure may currently limit the widespread application of this therapy. The results of this study suggest that after >75 cases, segmental ablation to isolate the pulmonary veins using fluoroscopy and conventional radiofrequency ablation usually is feasible in <3 hours.

Adult↗
PubMed2003

Rate-dependent effect of verapamil on atrial refractoriness.

OBJECTIVES: The purpose of this study was to determine whether verapamil has rate-dependent effects on the atrial effective refractory period (AERP). BACKGROUND: Block of calcium current (I(Ca)) and rapid component of the delayed rectifier potassium current (I(Kr)) by verapamil is frequency-dependent. This may result in variable effects of verapamil on the AERP, depending on the rate. METHODS: The subjects of this study were 30 adults with a mean age of 45 +/- 13 years who did not have structural heart disease. In 20 subjects, the AERP was measured at basic drive cycle lengths (BDCLs) of 650 to 250 ms, in 50 ms decrements, before and after infusion of 0.1 mg/kg verapamil. The effective refractory periods (ERPs) were measured in the setting of autonomic blockade in 10 subjects and without autonomic blockade in 10 subjects. Ten subjects served as a control group and received a saline infusion instead of verapamil. RESULTS: Verapamil significantly prolonged the AERP at BDCLs of 650 to 500 ms (p < 0.01 or p < 0.05) and significantly shortened the ERP at BDCLs of 300 and 250 ms (p < 0.01). In the control group, there were no significant differences between the baseline and post-saline measurements of ERP. CONCLUSIONS: Verapamil prolongs AERP at slow rates and shortens AERP at rapid rates. These findings are consistent with a predominant effect on I(Ca) at rapid rates and a predominant effect on I(Kr) at slow rates.

Adult↗
PubMed2003

Characteristics of rapid rhythms recorded within pulmonary veins during atrial fibrillation.

Rapid rhythms often arise in the pulmonary veins during atrial fibrillation (AF). The activation patterns within pulmonary veins during these rapid rhythms are not well described. In 39 patients with paroxysmal AF, ostial recordings were obtained during AF in 110 pulmonary veins with a decapolar distal ring catheter. Pulmonary vein tachycardia (PVT) was defined as a pulmonary vein (PV) rhythm that had a cycle length shorter than at the adjacent left atrium. During AF, PVT was recorded in 93% of PV's, usually in the form of intermittent bursts that had a mean duration of 1,325 +/- 647 ms and mean cycle length of 125 +/- 20 ms. The mean cycle length of continuous PVT's (141 +/- 25) was longer than the mean cycle length of intermittent bursts of PVT (P < 0.05). The intermittent PVT's were associated with a shorter left atrial cycle length than were the continuous PVT's. In 90% of PVTs, complex activation patterns attributable to simultaneous recordings from two or more overlapping fascicles were present at a segment of the pulmonary vein ostium, and the mean cycle length of these recordings was 80 +/- 32 ms. PVT during AF is much more often intermittent than continuous. The relationship between PVT cycle length and left atrial cycle length suggests that PVT's influence the left atrium during AF. PVT must be distinguished from recordings within PV's that have a short cycle length as a result of simultaneous recordings from two or more overlapping fascicles.

Aged↗
PubMed2003

Atrial electrogram amplitude and efficacy of cavotricuspid isthmus ablation for atrial flutter.

Large atrial electrogram amplitudes recorded in the cavotricuspid isthmus (CTI) may reflect thick atrial musculature. For this reason, in patients with atrial flutter, the efficacy of an application of conventional radiofrequency energy may be related to the amplitude of the local atrial electrogram. In 100 consecutive patients (mean age 59 +/- 13 years) with atrial flutter, contiguous applications of radiofrequency energy were delivered in the CTI. The criterion for complete CTI block was the presence of widely split double potentials (>110 ms) along the entire ablation line during pacing from the coronary sinus and posterolateral right atrium. The atrial electrogram amplitude was measured before and after applications of radiofrequency energy at sites of gaps in the ablation line. Complete CTI block was achieved in 90 (90%) of the 100 patients. The mean atrial electrogram amplitudes at gap sites where an application of radiofrequency energy did and did not result in complete block were 0.36 +/- 0.42 and 0.67 +/- 0.62 mV, respectively (P < 0.01). The positive and negative predictive values (for complete block) of a >/=50% decrease in electrogram amplitude after an application of radiofrequency energy were 100% and 35%, respectively. The mean atrial electrogram amplitude is larger at CTI sites where complete isthmus block cannot be achieved with conventional radiofrequency energy. The efficacy of conventional radiofrequency ablation may be improved by identifying areas in the CTI where the voltage is relatively low.

Atrial Flutter↗
PubMed2003

Effects of isoproterenol and amiodarone on the double potential interval after ablation of the cavotricuspid isthmus.

INTRODUCTION: A corridor of double potentials along the ablation line has been recognized to be an indicator of complete cavotricuspid isthmus block. Isoproterenol is used to confirm cavotricuspid isthmus block, but the effects of isoproterenol on the double potential interval (DPI), either in the absence or presence of amiodarone, are unknown. METHODS AND RESULTS: Thirty-two patients with isthmus-dependent atrial flutter underwent successful ablation of the cavotricuspid isthmus. The procedure was performed in the drug-free state in 23 patients, and 2 to 7 days after discontinuation of chronic amiodarone therapy in 9 patients. Electrograms recorded along the ablation line before and during isoproterenol infusion were analyzed after isthmus block was achieved. Double potentials were recorded along the entire ablation line upon achievement of complete isthmus block in all patients. The DPI in 9 patients treated with amiodarone was longer than in the other patients (147 +/- 32 msec vs 119 +/- 19 msec, P < 0.001). The DPI increased as the pacing cycle length shortened in patients treated with amiodarone, but not in the other patients. At all pacing cycle lengths, isoproterenol shortened the DPI to a greater extent in the patients treated with amiodarone than in the other patients. CONCLUSION: Amiodarone results in rate-dependent prolongation of the DPI during coronary sinus pacing after ablation of the cavotricuspid isthmus. Isoproterenol shortens the DPI despite the presence of complete isthmus block, and this effect is accentuated in the presence of amiodarone.

Adrenergic beta-Agonists↗
PubMed2003

Anatomy of the pulmonary veins in patients with atrial fibrillation and effects of segmental ostial ablation analyzed by computed tomography.

INTRODUCTION: The anatomic arrangement of pulmonary veins (PVs) is variable. No prior studies have quantitatively analyzed the effects of segmental ostial ablation on the PVs. The aim of this study was to determine the effect of segmental ostial radiofrequency ablation on PV anatomy in patients with atrial fibrillation (AF). METHODS AND RESULTS: Three-dimensional models of the PVs were constructed from computed tomographic (CT) scans in 58 patients with AF undergoing segmental ostial ablation to isolate the PVs and in 10 control subjects without a history of AF. CT scans were repeated approximately 4 months later. PV and left atrial dimensions were measured with digital calipers. Four separate PV ostia were present in 47 subjects; 3 ostia were present in 2 subjects; and 5 ostia were present in 9 subjects. The superior PVs had a larger ostium than the inferior PVs. Patients with AF had a larger left atrial area between the PV ostia and larger ostial diameters than the controls. Segmental ostial ablation resulted in a 1.5 +/- 3.2 mm narrowing of the ostial diameter. A 28% to 61% focal stenosis was present 7.6 +/- 2.2 mm from the ostium in 3% of 128 isolated PVs. There were no instances of symptomatic PV stenosis during a mean follow-up of 245 +/- 105 days. CONCLUSION: CT of the PVs allows identification of anatomic variants prior to catheter ablation procedures. Segmental ostial ablation results in a significant but small reduction in ostial diameter. Focal stenosis occurs infrequently and is attributable to delivery of radiofrequency energy within the PV.

Atrial Fibrillation↗
PubMed2003

Role of the coronary sinus in maintenance of atrial fibrillation.

INTRODUCTION: Bursts of tachycardia arising in the pulmonary veins may play an important role in perpetuating atrial fibrillation (AF). However, the role of the coronary sinus (CS) in the perpetuation of AF has been unclear. The aim of this study was to determine whether the CS plays a role in perpetuation of AF. METHODS AND RESULTS: Pulmonary vein isolation was performed by segmental ostial ablation with radiofrequency energy in 22 consecutive patients with paroxysmal AF. Bipolar and unipolar electrograms recorded in the left atrium and CS were analyzed during atrial pacing from the mitral annulus and during AF. There was a mean of 2.5 +/- 0.5 electrical connections between the CS and the left atrium. The electrical connections between the left atrium and CS were ablated with a mean of 6.2 +/- 2.7 minutes of radiofrequency energy applied along the atrial side of the inferior mitral annulus. During AF, episodes of intermittent tachycardia alternated between the left atrium and the CS. Among the 22 patients, sustained AF was still inducible in 9 after pulmonary vein isolation. After electrical disconnection of the CS from the left atrium, sustained AF was inducible in only 3 of these 9 patients. CONCLUSION: The CS may be a source of rapid repetitive electrical activity during AF. The lower probability of inducible sustained AF after electrical disconnection of the CS from the left atrium suggests that the CS may play a role in perpetuating AF.

Atrial Fibrillation↗
PubMed2003

Effect of atrial fibrillation duration on probability of immediate recurrence after transthoracic cardioversion.

INTRODUCTION: An immediate recurrence of atrial fibrillation (IRAF) appears to be more common after early restoration of sinus rhythm with an implantable atrial defibrillator than after elective transthoracic cardioversion, which suggests that the probability of IRAF may be related to the duration of AF. METHODS AND RESULTS: Transthoracic cardioversion was performed 85 +/- 187 days (range 7 minutes to 8 years) after the onset of atrial fibrillation in 315 patients (mean age 61 +/- 13 years). IRAF was defined as a recurrence of AF within 60 seconds after restoration of sinus rhythm. IRAF occurred in 56% of patients when cardioversion was performed within 1 hour of the onset of AF compared with 12% of patients when cardioversion was performed after 24 hours of AF (P < 0.001). The duration of AF was the only independent predictor of IRAF among the clinical variables of age, gender, structural heart disease, antiarrhythmic drug therapy, and cardioversion energy (P < 0.01). CONCLUSION: IRAF is more likely to occur when the duration of AF is <1 hour than when the duration is >24 hours. This observation has clinical implications for the most appropriate timing of cardioversion, particularly in patients who receive device therapy for AF.

Atrial Fibrillation↗
PubMed2002

Segmental ostial ablation to isolate the pulmonary veins during atrial fibrillation: feasibility and mechanistic insights.

BACKGROUND: The purpose of this study was to determine the feasibility and mechanistic implications of segmental pulmonary vein (PV) ostial ablation during atrial fibrillation (AF). METHODS AND RESULTS: Forty consecutive patients underwent PV isolation for AF. Among 125 PVs targeted for isolation, ablation was performed during AF in 70 veins and during sinus rhythm in 55 veins. A decapolar Lasso catheter was positioned near the ostium. During AF, ostial ablation was performed near the Lasso catheter electrodes that recorded a tachycardia with a cycle length shorter than in the adjacent left atrium. During sinus rhythm, ostial ablation was guided by PV potentials. Complete PV isolation was achieved in 70 PVs (100%) ablated during AF and in 53 PVs (96%) ablated during sinus rhythm (P=0.4). The mean durations of radiofrequency energy needed for isolation were 7.4+/-4.4 and 5.2+/-3.9 minutes during AF and sinus rhythm, respectively (P<0.01). Before ablation, an immediate recurrence of AF (IRAF), occurred after cardioversion in 18 of 40 patients, and IRAF was consistently abolished by PV isolation. The probability of AF termination during isolation of a PV was directly related to the extent of tachycardia in that vein. As more PVs were isolated, induction of persistent AF by rapid pacing became less likely. CONCLUSIONS: Segmental ostial ablation guided by PV tachycardia during AF is feasible and as efficacious as during sinus rhythm. The responses to cardioversion, ablation, and rapid pacing observed in this study imply that IRAF is triggered by the PVs and that PV tachycardias may play an important role in the perpetuation of AF.

Atrial Fibrillation↗
PubMed2002

Comparison of amiodarone versus ibutilide for the prevention of immediate recurrences of atrial fibrillation during pulmonary vein isolation.

During segmental ostial ablation for pulmonary vein isolation, pulmonary vein potentials are easily identified during sinus rhythm or left atrial pacing. Therefore, maintenance of atrial fibrillation (AF) during the procedure is desirable. However, cardioversion is occasionally followed by an immediate recurrence of AF. This study compared the efficacy of ibutilide and amiodarone in preventing immediate recurrences of AF in patients who underwent pulmonary vein isolation. The subjects of this study were 25 patients (mean age 56 +/- 10 years) who underwent pulmonary vein isolation for AF who had an immediate recurrence of AF within 60 seconds after 2 transthoracic cardioversions. The patients were randomized to receive an infusion of either 300 mg of amiodarone over 10 minutes or 1 mg of ibutilide over 5 minutes. Cardioversion was repeated 15 minutes after the drug infusion. If immediate recurrences of AF occurred 2 more times, the alternative study drug was administered, and cardioversion was repeated. Immediate recurrences of AF were suppressed by amiodarone in 8 of 10 patients (80%), and by ibutilide in 9 of 15 patients (60%, p = 0.4). After crossover, immediate recurrence of AF was suppressed in 2 of 6 patients (33%) by amiodarone, and in 1 of 2 patients (50%) by ibutilide (p = 0.6). Ibutilide and amiodarone, when used alone or in combination, prevented immediate recurrences of AF in 20 of 25 patients (80%). There were no adverse drug effects. Ibutilide and amiodarone were equally effective in suppressing immediate recurrences of AF. Overall, immediate recurrences of AF can be prevented by amiodarone and/or ibutilide in 80% of patients.

Aged↗
PubMed2002

Clinical significance of early recurrences of atrial fibrillation after pulmonary vein isolation.

OBJECTIVES: The purposes of this study were to describe the prevalence of early recurrences of atrial fibrillation (ERAF) that occur within two weeks after pulmonary vein (PV) isolation, and to determine whether ERAF is predictive of long-term outcome after PV isolation. BACKGROUND: Atrial fibrillation (AF) sometimes recurs within days after PV isolation and may prompt an early repeat intervention. METHODS: Segmental PV isolation was performed using radiofrequency energy in 110 consecutive patients (mean age 53 +/- 11 years) with paroxysmal (93 patients) or persistent (17 patients) AF. Three to four PVs were targeted for isolation in all patients. Pulmonary vein isolation was complete in 338 of the 358 PVs that were targeted (94%). RESULTS: Early recurrences of AF occurred in 39 of 110 patients (35%) at a mean of 3.7 +/- 3.5 days after the procedure. The prevalence of ERAF was similar in patients with paroxysmal and persistent AF (33% and 47%, respectively, p = 0.4). Beyond the first two weeks, at 208 +/- 125 days of follow-up, 60 of the 71 patients without ERAF (85%) and 12 of the 39 patients with ERAF (31%) were free of recurrent AF in the absence of antiarrhythmic drug therapy (p < 0.001). CONCLUSIONS: Early recurrences of AF occur in approximately 35% of patients within two weeks after isolation of three to four PVs, and are associated with a lower long-term success rate than in patients without ERAF. However, approximately 30% of patients with ERAF have no further symptomatic AF during long-term follow-up. Therefore, temporary antiarrhythmic drug therapy may be more appropriate than early repeat ablation in patients with ERAF.

Anti-Arrhythmia Agents↗
PubMed2002

Pulmonary vein isolation for paroxysmal and persistent atrial fibrillation.

BACKGROUND: The pulmonary veins (PVs) have been demonstrated to often play an important role in generating atrial fibrillation (AF). The purpose of this study was to determine the safety and efficacy of segmental PV isolation in patients with paroxysmal or persistent AF. METHODS AND RESULTS: In 70 consecutive patients (mean age, 53 +/- 11 years) with paroxysmal (58) or persistent (12) AF, segmental PV isolation guided by ostial PV potentials was performed. The left superior, left inferior, and right superior PVs were targeted for isolation in all patients, and the right inferior PV was isolated in 20 patients. Among the 230 targeted PVs, 217 (94%) were completely isolated, with a mean of 6.5 +/- 4.2 minutes of radiofrequency energy applied at a maximum power setting of 35 W. A second PV isolation procedure was performed in 6 patients (9%). At 5 months of follow-up, 70% of patients with paroxysmal and 22% of patients with persistent AF were free from recurrent AF (P<0.001), and 83% of patients with paroxysmal AF were either free of symptomatic AF or had significant improvement. Among various clinical characteristics, only paroxysmal AF was an independent predictor of freedom from recurrence of AF (P<0.05). One patient developed unilateral quadrantopsia after the procedure. There were no other complications. CONCLUSIONS: With a segmental isolation approach that targets at least 3 PVs, a clinically satisfactory result can be achieved in >80% of patients with paroxysmal AF. The clinical efficacy of pulmonary vein isolation is much lower when AF is persistent than when it is paroxysmal.

Adult↗
PubMed2002

Mechanistic significance of intermittent pulmonary vein tachycardia in patients with atrial fibrillation.

INTRODUCTION: The significance of intermittent tachycardia within a pulmonary vein (PV) during an episode of atrial fibrillation (AF) is unclear. The aim of this study was to determine the role that intermittent PV tachycardias play in AF. METHODS AND RESULTS: In 56 patients with AF, segmental ostial ablation guided by PV potentials was performed to isolate the PVs. The characteristics of intermittent PV tachycardias and the inducibility of AF before and after PV isolation were analyzed prospectively. During AF, a PV tachycardia (mean cycle length 130 +/- 30 msec) with exit block to the left atrium was present in 93% of left superior, 80% of left inferior, 73% of right superior, and 7% of right inferior PVs. The site of shortest cycle length during AF alternated between the PVs and left atrium 1 to 13 times per minute. Complete isolation was achieved in 168 (94%) of 178 targeted PVs. In 99% of PVs, tachycardia resolved upon isolation. AF was persistent before and after PV isolation in 100% and 27% of patients, respectively (P < 0.001). CONCLUSION: Intermittent bursts of tachycardia are observed within multiple PVs during persistent AF in a majority of patients. After PV isolation, PV tachycardias almost always resolve, and AF is less likely to be inducible or persistent. These observations suggest a dynamic interplay between the atria and PVs, with intermittent bursts of PV tachycardia being dependent on left atrial input and with the probability of persistent AF diminishing when PV tachycardias are eliminated by PV isolation.

Analysis of Variance↗
PubMed2002

Randomized comparison of anatomic and electrogram mapping approaches to ablation of typical atrial flutter.

INTRODUCTION: The cavotricuspid isthmus can be ablated using an anatomic approach or an electrogram mapping approach in which sites at which there is a gap in the line of block are targeted. The aim of this study was to compare the anatomic and electrogram mapping approaches for creating a line of block in the cavotricuspid isthmus after an initial, unsuccessful anatomically directed ablation line. METHODS AND RESULTS: The subjects of this study were 63 patients with isthmus-dependent atrial flutter in whom a single series of contiguous applications of radiofrequency energy guided by fluoroscopy in the cavotricuspid isthmus did not result in complete block. The patients were randomly assigned to additional ablation on an anatomic basis (n = 31) or guided by single potentials or narrowly split double potentials during coronary sinus pacing (n = 32). After every 15 applications of radiofrequency energy, the alternate approach was used until complete block was achieved. Before cross-over, complete block was achieved in 6 patients (19%) with the anatomic approach compared with 19 patients (59%) with the electrogram mapping approach (P < 0.005). The electrogram mapping approach also was more effective than the anatomic approach in achieving complete isthmus block after the first cross-over (72% vs 23%, P < 0.005) and after the second cross-over (80% vs 42%, P < 0.05). CONCLUSION: When there is incomplete block after an initial series of applications of radiofrequency energy in the cavotricuspid isthmus, complete block is achieved more efficiently with an electrogram mapping approach than with an anatomic approach.

Atrial Flutter↗
PubMed2002

Randomized comparison of bipolar versus unipolar plus bipolar recordings during segmental ostial ablation of pulmonary veins.

INTRODUCTION: Segmental ostial ablation to isolate pulmonary veins is guided by pulmonary vein potentials. The aim of this prospective randomized study was to compare the utility of unipolar plus bipolar electrograms versus only bipolar electrograms as a guide for segmental ablation to isolate the pulmonary veins in patients with atrial fibrillation. METHODS AND RESULTS: Isolation of the left superior, right superior, and left inferior pulmonary veins was attempted in 44 patients (35 men and 9 women; mean age 54 +/- 10 years) with paroxysmal atrial fibrillation. A decapolar Lasso catheter was positioned in the pulmonary veins, near the ostium, and a conventional ablation catheter was used for segmental ablation aimed at elimination of all pulmonary vein potentials. One hundred fourteen pulmonary veins were randomly assigned for ostial ablation guided by either bipolar or unipolar plus bipolar recordings. Electrical isolation was achieved in 51 (96%) of 53 pulmonary veins randomized to the bipolar approach, and 57 (93%) of 61 pulmonary veins randomized to the unipolar plus bipolar approach (P = 0.7). In the unipolar plus bipolar group, the total duration of radiofrequency energy needed to achieve isolation, 5.5 +/- 2.8 minutes/vein, was significant shorter than in the bipolar group, 7.6 +/- 4.1 minutes/vein (P < 0.01). Mean procedure and fluoroscopy durations per vein were 19% to 28% shorter in the unipolar plus bipolar group. CONCLUSION: Segmental ostial ablation to isolate the pulmonary veins can be achieved more efficiently and with less radiofrequency energy when guided by both unipolar and bipolar recordings than by bipolar recordings alone.

Adult↗