Tachycardia detection in first-generation biventricular pacemaker-implantable cardioverter defibr... more Tachycardia detection in first-generation biventricular pacemaker-implantable cardioverter defibrillators (BiV ICD) occurs through both the right ventricular (RV) and left ventricular (LV) leads, creating the potential for inappropriate detection and therapies. Little is known regarding the prevalence and management of patients with BiV ICDs and inappropriate detection. A transvenous, first-generation BiV ICD was implanted in 77 consecutive patients (age 61 +/- 11 years) for drug-refractory heart failure. The mean New York Heart Association class, QRS duration, and ejection fraction were 3.1 +/- 0.4, 168 +/- 24 ms, and 0.19 +/- 0.07, respectively. Among the 77 patients, 17 (22%) experienced inappropriate detection at a mean of 154 +/- 140 days after implantation. Fifteen of the 17 patients (88%) experienced inappropriate ICD therapy. In 16 of the 17 (94%) patients, the cause of inappropriate detection was double counting during sinus (8) or atrial rhythm (3), and nonsustained ventricular tachycardia (5). Despite reprogramming of the ICD, 9 patients (53%) required an additional procedure because of inappropriate therapies, including an upgrade to a dedicated BiV ICD (5), revision of the LV lead (2), ablation of the atrioventricular junction (1), and repeat defibrillation threshold testing (2). Inappropriate detection in patients with a first-generation BiV ICD is common and often results in inappropriate ICD therapy. The most common mechanism of inappropriate detection is double counting that often creates the need for additional procedures. Although devices in which tachycardia detection occurs only through the RV lead now are available, close follow-up of the many patients who received a first-generation BiV ICD is necessary.
It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), an... more It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), and an estimated 30% of patients with AF are unaware of their diagnosis (silent AF). The purpose of this study was to test a new technology for contactless detection of AF based on facial video recordings. The proposed technique uses a camera to record an individual's face and extract the subtle beat-to-beat variations of skin color reflecting the cardiac pulsatile signal. In a group of adults referred for electrical cardioversion, we recorded the ECG and the video of the subjects' face before and after electrical cardioversion. We extracted the beat-to-beat pulse rates expressed as pulses per minute (ppm) from the videoplethysmographic (VPG) signal acquired using a standard web camera. We introduce a novel quantifier of pulse variability called the pulse harmonic strength (PHS) and report its ability to detect the presence of AF. Eleven subjects (8 male; age 65 ± 6 years) were included in the study. The VPG and ECG-based rates were statistically different between the AF and sinus rhythm periods: 72 ± 9 ppm vs 57 ± 7 ppm (P < .0001) for VPG and 80 ± 17 bpm vs 56 ± 7 bpm (P < .0001) for ECG signals. Among the 407 epochs of 15 seconds of synchronized ECG and VPG signals, PHS was associated with a 20% detection error rate, and the error rates of the automatic ECG-based measurements ranged between 17% and 29%. Our preliminary results support the concept that contactless video-based monitoring of the human face for detection of abnormal pulse variability due to AF is feasible.
A 51-year-old woman presented with an episode of syncope. Upon further review she was found to ha... more A 51-year-old woman presented with an episode of syncope. Upon further review she was found to have a typical Brugada type pattern on her electrocardiogram. She did not have evidence for structural heart disease. At electrophysiological testing she was found to have marked infrahisian conduction disease and had easily inducible polymorphic ventricular tachycardia. She underwent implantation of a dual-chamber implantable cardioverter defibrillator (ICD) and family screening was recommended. Genetic analysis revealed a novel nonsense mutation in the gene encoding for the sodium channel (SCN5A). Five months after ICD implantation the patient had an episode of ventricular fibrillation documented on ICD interrogation. This case is unique as it is consistent with an overlap syndrome, namely both Brugada Syndrome and distal atrioventricular (AV) conduction disease secondary to a novel SCN5A mutation in a young female. This finding highlights the phenotypic heterogeneity of novel SCN5A mutations.
An immediate recurrence of AF may occur after restoration of sinus rhythm. Although pulmonary vei... more An immediate recurrence of AF may occur after restoration of sinus rhythm. Although pulmonary vein (PV) isolation has been shown to prevent immediate recurrence of AF, the specific trigger for immediate recurrence of AF has not been described. In 89 consecutive patients (mean age 53 +/- 11 years) who had sinus rhythm restored by spontaneous or transthoracic cardioversion in the course of a PV isolation procedure, electrograms recorded within a PV and in the adjacent left atrium were analyzed to determine the mechanism of initiation of immediate recurrence of AF. Immediate recurrence of AF was defined as a recurrence of AF within 90 seconds after restoration of sinus rhythm. There were 124 episodes of immediate recurrence of AF at a mean of 18 +/- 23 seconds after cardioversion. Recordings within the PV that triggered the immediate recurrence of AF were available in 23 (19%) of the 124 immediate recurrence of AF episodes. Among these 23 episodes of immediate recurrence of AF, all (100%) were triggered by a burst of PV tachycardia (P < 0.001). The coupling interval and prematurity index (coupling interval/preceding sinus cycle length) of the premature depolarizations that did and did not trigger immediate recurrence of AF were 246 +/- 67 ms and 0.30 +/- 0.11 vs 378 +/- 117 ms and 0.49 +/- 0.16, respectively (P < 0.01). Immediate recurrence of AF was abolished by PV isolation. The mechanism of immediate recurrence of AF is a burst of PV tachycardia, not a single premature depolarization. Immediate recurrence of AF identifies patients with AF in whom the PVs may play a major role in the initiation of AF.
Recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) has been wel... more Recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) has been well established and is in part related to left atrial (LA) size. The purpose of this study was to assess the predictive capability of LA diameter (LAD) and LA volume (LAV) by echocardiography and computed tomography (CT) to determine success in patients undergoing RFCA of AF. Eighty-eight patients with paroxysmal or persistent AF who had undergone RFCA and had a prior transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), and CT were enrolled in the study. TTE LADs and LV ejection fraction as well as TEE LADs and LAVs in three views were recorded. CT LAVs were also recorded. Clinical parameters prior to ablation as well as at 1-year follow-up were assessed. A total of 40 (45%) patients with paroxysmal AF and 48 (55%) patients with persistent AF were analyzed. Paroxysmal AF patients had a RFCA success rate of 88% at 1 year with persistent AF patients having a 52% success rate (P < 0.001). A CT-derived LAV >or= 117 cc was associated with an odds ratio (OR) for recurrence of 4.8 (95% confidence interval [CI]=[1.4-16.4], P = 0.01) while a LAV >or=130 cc was associated with an OR for recurrence of 22.0 (95% CI =[2.5-191.0], P = 0.005) after adjustment for persistent AF. LA dimensions and AF type are highly predictive of AF recurrence following RFCA. LAV by CT has significant predictive benefit over standard LADs in severely enlarged atria even after adjustment for AF type.
Electrical isolation of the left superior, left inferior, and right superior pulmonary veins (PVs... more 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.
Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden car... more Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden cardiac death in patients with left ventricular dysfunction. The influence of right ventricular (RV) function on ICD therapy for sudden cardiac death (SCD) is not known. We retrospectively studied 222 patients receiving an ICD for primary prevention of SCD. Baseline clinical and echocardiographic data were gathered. RV systolic function was qualitatively assessed as normal or abnormal (described as mildly, moderately, or severely reduced). Primary endpoint was combined ICD therapy or death and secondary endpoint was ICD therapy alone. The mean follow-up was 940 +/- 522 days. The mean left ventricular ejection fraction was 0.23 +/- 0.07. By Kaplan-Meier analysis, RV dysfunction was predictive of combined ICD therapy or death when comparing between normal and abnormal RV function (P = 0.008) and among qualitative ranges of RV function (P = 0.012). RV dysfunction was not predictive of ICD therapy alone with either type of classification. After adjusting for clinical covariates, severe RV dysfunction was predictive of the combined endpoint of ICD therapy or death (HR 2.02, 95% CI 1.04-3.92, P = 0.037). Severe RV dysfunction appears to be an independent predictor of the combined endpoint of ICD therapy or death. RV dysfunction does not reliably predict the incidence of ICD therapy alone.
Journal of Interventional Cardiac Electrophysiology, 2005
Venous complications of pacemaker/ implantable cardioverter defibrillator (ICD) system implantati... more Venous complications of pacemaker/ implantable cardioverter defibrillator (ICD) system implantation rarely cause immediate clinical problems. The challenge starts when patients come for system revision or upgrade. Numerous reports of venous complications such as stenosis, occlusions, and superior vena cava syndrome have been published. We reviewed current knowledge of these complications, management, and their impact on upgrade/revision procedures. One study has suggested that intravenous lead infection promotes local vein stenosis. Another found that the presence of a temporary wire before implantation is associated with an increased risk of stenosis. Although data for ICD leads is based only on three studies-it suggests that the rate of venous complications is very similar to that of pacing systems, and probably data from pacing leads can be extrapolated to ICD leads. Despite 40 years of experience with transcutaneous implanted intravenous pacing systems and dozens of studies, we were unable to identify clear risk factors (confirmed by independent studies) that lead to venous stenosis. Neither the hardware (lead size, number and material) nor the access site choice (cephalic cut down, subclavian or axillary puncture) appears to affect rate of venous complications. A few factors were proposed as predictors of severe venous stenosis/occlusion: presence of multiple pacemaker leads (compared to a single lead), use of hormone therapy, personal history of venous thrombosis, the presence of temporary wire before implantation, previous presence of a pacemaker (ICD as an upgrade) and the use of dual-coil leads. Anticoagulant therapy (for other reasons than pacemaker lead) seemed to have protective antithrombotic effect.
The long-term efficacy of radiofrequency catheter ablation of atrial fibrillation (AF) has been b... more The long-term efficacy of radiofrequency catheter ablation of atrial fibrillation (AF) has been based on patient-reported symptoms suggestive of AF. However, asymptomatic recurrences of AF may remain undetected. The aim of this study was to determine the prevalence of asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for AF. Among 244 consecutive patients (mean age 53 +/- 11 years) who underwent a pulmonary vein isolation procedure for symptomatic paroxysmal AF and who reported no symptoms of recurrent AF at > or =6 months after the procedure, 60 patients with a history of > or =1 episode of AF per week were asked to participate in this study. Preablation, these patients had experienced 19 +/- 13 episodes of AF per month. The patients were provided with a patient-activated transtelephonic event recorder for 30 days, a mean of 642 +/- 195 days after the ablation procedure, and were asked to record and transmit recordings on a daily basis and whenever they felt palpitations. Seven patients (12%) felt palpitations during the study, although they had not experienced symptoms previously. Each of these 7 patients had an episode of AF documented with the event monitor during symptoms. In these 7 patients, the mean number of episodes per month decreased from 19 +/- 14 preablation to 3 +/- 1 postablation (P < 0.001). Among the 53 asymptomatic patients, an episode of AF was captured in 1 (2%) patient during the study period. Asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for symptomatic paroxysmal AF are infrequent.
Tachycardia detection in first-generation biventricular pacemaker-implantable cardioverter defibr... more Tachycardia detection in first-generation biventricular pacemaker-implantable cardioverter defibrillators (BiV ICD) occurs through both the right ventricular (RV) and left ventricular (LV) leads, creating the potential for inappropriate detection and therapies. Little is known regarding the prevalence and management of patients with BiV ICDs and inappropriate detection. A transvenous, first-generation BiV ICD was implanted in 77 consecutive patients (age 61 +/- 11 years) for drug-refractory heart failure. The mean New York Heart Association class, QRS duration, and ejection fraction were 3.1 +/- 0.4, 168 +/- 24 ms, and 0.19 +/- 0.07, respectively. Among the 77 patients, 17 (22%) experienced inappropriate detection at a mean of 154 +/- 140 days after implantation. Fifteen of the 17 patients (88%) experienced inappropriate ICD therapy. In 16 of the 17 (94%) patients, the cause of inappropriate detection was double counting during sinus (8) or atrial rhythm (3), and nonsustained ventricular tachycardia (5). Despite reprogramming of the ICD, 9 patients (53%) required an additional procedure because of inappropriate therapies, including an upgrade to a dedicated BiV ICD (5), revision of the LV lead (2), ablation of the atrioventricular junction (1), and repeat defibrillation threshold testing (2). Inappropriate detection in patients with a first-generation BiV ICD is common and often results in inappropriate ICD therapy. The most common mechanism of inappropriate detection is double counting that often creates the need for additional procedures. Although devices in which tachycardia detection occurs only through the RV lead now are available, close follow-up of the many patients who received a first-generation BiV ICD is necessary.
It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), an... more It is estimated that 33.5 million people in the world have developed atrial fibrillation (AF), and an estimated 30% of patients with AF are unaware of their diagnosis (silent AF). The purpose of this study was to test a new technology for contactless detection of AF based on facial video recordings. The proposed technique uses a camera to record an individual's face and extract the subtle beat-to-beat variations of skin color reflecting the cardiac pulsatile signal. In a group of adults referred for electrical cardioversion, we recorded the ECG and the video of the subjects' face before and after electrical cardioversion. We extracted the beat-to-beat pulse rates expressed as pulses per minute (ppm) from the videoplethysmographic (VPG) signal acquired using a standard web camera. We introduce a novel quantifier of pulse variability called the pulse harmonic strength (PHS) and report its ability to detect the presence of AF. Eleven subjects (8 male; age 65 ± 6 years) were included in the study. The VPG and ECG-based rates were statistically different between the AF and sinus rhythm periods: 72 ± 9 ppm vs 57 ± 7 ppm (P < .0001) for VPG and 80 ± 17 bpm vs 56 ± 7 bpm (P < .0001) for ECG signals. Among the 407 epochs of 15 seconds of synchronized ECG and VPG signals, PHS was associated with a 20% detection error rate, and the error rates of the automatic ECG-based measurements ranged between 17% and 29%. Our preliminary results support the concept that contactless video-based monitoring of the human face for detection of abnormal pulse variability due to AF is feasible.
A 51-year-old woman presented with an episode of syncope. Upon further review she was found to ha... more A 51-year-old woman presented with an episode of syncope. Upon further review she was found to have a typical Brugada type pattern on her electrocardiogram. She did not have evidence for structural heart disease. At electrophysiological testing she was found to have marked infrahisian conduction disease and had easily inducible polymorphic ventricular tachycardia. She underwent implantation of a dual-chamber implantable cardioverter defibrillator (ICD) and family screening was recommended. Genetic analysis revealed a novel nonsense mutation in the gene encoding for the sodium channel (SCN5A). Five months after ICD implantation the patient had an episode of ventricular fibrillation documented on ICD interrogation. This case is unique as it is consistent with an overlap syndrome, namely both Brugada Syndrome and distal atrioventricular (AV) conduction disease secondary to a novel SCN5A mutation in a young female. This finding highlights the phenotypic heterogeneity of novel SCN5A mutations.
An immediate recurrence of AF may occur after restoration of sinus rhythm. Although pulmonary vei... more An immediate recurrence of AF may occur after restoration of sinus rhythm. Although pulmonary vein (PV) isolation has been shown to prevent immediate recurrence of AF, the specific trigger for immediate recurrence of AF has not been described. In 89 consecutive patients (mean age 53 +/- 11 years) who had sinus rhythm restored by spontaneous or transthoracic cardioversion in the course of a PV isolation procedure, electrograms recorded within a PV and in the adjacent left atrium were analyzed to determine the mechanism of initiation of immediate recurrence of AF. Immediate recurrence of AF was defined as a recurrence of AF within 90 seconds after restoration of sinus rhythm. There were 124 episodes of immediate recurrence of AF at a mean of 18 +/- 23 seconds after cardioversion. Recordings within the PV that triggered the immediate recurrence of AF were available in 23 (19%) of the 124 immediate recurrence of AF episodes. Among these 23 episodes of immediate recurrence of AF, all (100%) were triggered by a burst of PV tachycardia (P < 0.001). The coupling interval and prematurity index (coupling interval/preceding sinus cycle length) of the premature depolarizations that did and did not trigger immediate recurrence of AF were 246 +/- 67 ms and 0.30 +/- 0.11 vs 378 +/- 117 ms and 0.49 +/- 0.16, respectively (P < 0.01). Immediate recurrence of AF was abolished by PV isolation. The mechanism of immediate recurrence of AF is a burst of PV tachycardia, not a single premature depolarization. Immediate recurrence of AF identifies patients with AF in whom the PVs may play a major role in the initiation of AF.
Recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) has been wel... more Recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA) has been well established and is in part related to left atrial (LA) size. The purpose of this study was to assess the predictive capability of LA diameter (LAD) and LA volume (LAV) by echocardiography and computed tomography (CT) to determine success in patients undergoing RFCA of AF. Eighty-eight patients with paroxysmal or persistent AF who had undergone RFCA and had a prior transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), and CT were enrolled in the study. TTE LADs and LV ejection fraction as well as TEE LADs and LAVs in three views were recorded. CT LAVs were also recorded. Clinical parameters prior to ablation as well as at 1-year follow-up were assessed. A total of 40 (45%) patients with paroxysmal AF and 48 (55%) patients with persistent AF were analyzed. Paroxysmal AF patients had a RFCA success rate of 88% at 1 year with persistent AF patients having a 52% success rate (P < 0.001). A CT-derived LAV >or= 117 cc was associated with an odds ratio (OR) for recurrence of 4.8 (95% confidence interval [CI]=[1.4-16.4], P = 0.01) while a LAV >or=130 cc was associated with an OR for recurrence of 22.0 (95% CI =[2.5-191.0], P = 0.005) after adjustment for persistent AF. LA dimensions and AF type are highly predictive of AF recurrence following RFCA. LAV by CT has significant predictive benefit over standard LADs in severely enlarged atria even after adjustment for AF type.
Electrical isolation of the left superior, left inferior, and right superior pulmonary veins (PVs... more 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.
Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden car... more Implantable cardioverter-defibrillator (ICD) therapy is well established in preventing sudden cardiac death in patients with left ventricular dysfunction. The influence of right ventricular (RV) function on ICD therapy for sudden cardiac death (SCD) is not known. We retrospectively studied 222 patients receiving an ICD for primary prevention of SCD. Baseline clinical and echocardiographic data were gathered. RV systolic function was qualitatively assessed as normal or abnormal (described as mildly, moderately, or severely reduced). Primary endpoint was combined ICD therapy or death and secondary endpoint was ICD therapy alone. The mean follow-up was 940 +/- 522 days. The mean left ventricular ejection fraction was 0.23 +/- 0.07. By Kaplan-Meier analysis, RV dysfunction was predictive of combined ICD therapy or death when comparing between normal and abnormal RV function (P = 0.008) and among qualitative ranges of RV function (P = 0.012). RV dysfunction was not predictive of ICD therapy alone with either type of classification. After adjusting for clinical covariates, severe RV dysfunction was predictive of the combined endpoint of ICD therapy or death (HR 2.02, 95% CI 1.04-3.92, P = 0.037). Severe RV dysfunction appears to be an independent predictor of the combined endpoint of ICD therapy or death. RV dysfunction does not reliably predict the incidence of ICD therapy alone.
Journal of Interventional Cardiac Electrophysiology, 2005
Venous complications of pacemaker/ implantable cardioverter defibrillator (ICD) system implantati... more Venous complications of pacemaker/ implantable cardioverter defibrillator (ICD) system implantation rarely cause immediate clinical problems. The challenge starts when patients come for system revision or upgrade. Numerous reports of venous complications such as stenosis, occlusions, and superior vena cava syndrome have been published. We reviewed current knowledge of these complications, management, and their impact on upgrade/revision procedures. One study has suggested that intravenous lead infection promotes local vein stenosis. Another found that the presence of a temporary wire before implantation is associated with an increased risk of stenosis. Although data for ICD leads is based only on three studies-it suggests that the rate of venous complications is very similar to that of pacing systems, and probably data from pacing leads can be extrapolated to ICD leads. Despite 40 years of experience with transcutaneous implanted intravenous pacing systems and dozens of studies, we were unable to identify clear risk factors (confirmed by independent studies) that lead to venous stenosis. Neither the hardware (lead size, number and material) nor the access site choice (cephalic cut down, subclavian or axillary puncture) appears to affect rate of venous complications. A few factors were proposed as predictors of severe venous stenosis/occlusion: presence of multiple pacemaker leads (compared to a single lead), use of hormone therapy, personal history of venous thrombosis, the presence of temporary wire before implantation, previous presence of a pacemaker (ICD as an upgrade) and the use of dual-coil leads. Anticoagulant therapy (for other reasons than pacemaker lead) seemed to have protective antithrombotic effect.
The long-term efficacy of radiofrequency catheter ablation of atrial fibrillation (AF) has been b... more The long-term efficacy of radiofrequency catheter ablation of atrial fibrillation (AF) has been based on patient-reported symptoms suggestive of AF. However, asymptomatic recurrences of AF may remain undetected. The aim of this study was to determine the prevalence of asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for AF. Among 244 consecutive patients (mean age 53 +/- 11 years) who underwent a pulmonary vein isolation procedure for symptomatic paroxysmal AF and who reported no symptoms of recurrent AF at > or =6 months after the procedure, 60 patients with a history of > or =1 episode of AF per week were asked to participate in this study. Preablation, these patients had experienced 19 +/- 13 episodes of AF per month. The patients were provided with a patient-activated transtelephonic event recorder for 30 days, a mean of 642 +/- 195 days after the ablation procedure, and were asked to record and transmit recordings on a daily basis and whenever they felt palpitations. Seven patients (12%) felt palpitations during the study, although they had not experienced symptoms previously. Each of these 7 patients had an episode of AF documented with the event monitor during symptoms. In these 7 patients, the mean number of episodes per month decreased from 19 +/- 14 preablation to 3 +/- 1 postablation (P < 0.001). Among the 53 asymptomatic patients, an episode of AF was captured in 1 (2%) patient during the study period. Asymptomatic recurrences of AF after an apparently successful catheter ablation procedure for symptomatic paroxysmal AF are infrequent.
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