Shibu Mathew

Catheter Ablation of Long-Standing Persistent Atrial Fibrillation: 5-Year Outcomes of the Hamburg Sequential Ablation Strategy

OBJECTIVES This study describes the 5-year efficacy of catheter ablation for long-standing persistent atrial fibrillation (LS-AF). BACKGROUND Long-term outcome data after catheter ablation for LS-AF are limited. METHODS Long-term follow-up of 56 months (range 49 to 67 months) was performed in 202 patients (age 61 ± 9 years) who underwent the sequential ablation strategy for symptomatic LS-AF. Initial ablation strategy was circumferential pulmonary vein isolation (PVI). Additional ablation was performed only in acute PVI nonresponder, if direct current cardioversion failed after PVI. RESULTS After the first ablation procedure, sinus rhythm was documented in 41 of 202 (20.3%) patients. After multiple procedures, sinus rhythm was maintained in 91 of 202 (45.0%) patients, including 24 patients receiving antiarrhythmic drugs. In 105 patients, PVI was the sole ablative therapy, 49 (46.7%) of those patients remained in sinus rhythm during follow-up. Patients with a total AF duration of <2 years had a significantly higher ablation success rate than patients whose AF duration was >2 years (76.5% vs. 42.2%, respectively; p = 0.033). Persistent AF duration (hazard ratio: 1.09 [95% confidence interval: 1.04 to 1.13]; p < 0.001) independently predicted arrhythmia recurrences, and acute PVI responders had a reduced risk of relapse (hazard ratio: 0.57 [95% confidence interval: 0.41 to 0.78]; p < 0.001) after the first ablation. CONCLUSIONS During 5-year follow-up, single- and multiple ablation procedure success was 20% and 45%, respectively, for patients with LS-AF. For patients with a total AF duration of <2 years, the outcomes were favorable.

One-Year Clinical Outcome After Pulmonary Vein Isolation Using the Second-Generation 28-mm Cryoballoon

Background—The use of second-generation cryoballoon for pulmonary vein isolation in patients with paroxysmal atrial fibrillation has demonstrated encouraging acute and mid-term results. Long-term outcome data are not yet available. Methods and Results—Fifty patients (18 women; mean age, 61±11 years; mean left atrial diameter, 43±5 mm) with paroxysmal (36 of 50 patients; 72%) or short-standing (<3-month duration) persistent atrial fibrillation (14 of 50 patients; 28%) underwent cryoballoon-based pulmonary vein isolation. Freeze cycle duration was 240 seconds. After successful pulmonary vein isolation, a bonus freeze was applied. Follow-up was based on outpatient clinic visits at 3, 6, and 12 months including Holter-ECGs and telephonic interviews. Recurrence was defined as a symptomatic or documented arrhythmia episode >30 seconds excluding a 3-month blanking period. A total of 192 pulmonary veins were identified, and 191 of 192 (99%) pulmonary veins were successfully isolated. Phrenic nerve palsy occurred in 1 of 50 (2%) patients. Follow-up was available for 49 of 50 (98%) patients with a mean follow-up duration of 440±39 days. Thirty-nine of 49 (80%) patients remained in stable sinus rhythm. Of 8 of 10 patients with arrhythmia recurrence, a second procedure using radiofrequency ablation demonstrated left atrial to pulmonary vein reconduction. Conclusions—The use of second-generation 28-mm cryoballoon for pulmonary vein isolation results in an 80% 1-year success rate.

Increased incidence of esophageal thermal lesions using the second-generation 28-mm cryoballoon.

Background—Pulmonary vein isolation is an established treatment option for atrial fibrillation. To date, the incidence and quality of ablation-induced esophageal thermal lesions (ETLs) using the recently introduced second-generation cryoballoon (CB, ArcticFront Advance, Medtronic) is unknown. Methods and Results—In patients with drug-refractory paroxysmal atrial fibrillation or short-standing persistent atrial fibrillation, pulmonary vein (PV) isolation was performed using the second-generation CB. The endoluminal esophageal temperature was monitored via a temperature probe. After PV isolation, esophagogastroduodenoscopy (EGD) was performed to assess the incidence of ETLs. In 50 patients (18 women; age, 61±11 years; left atrial diameter, 43±5 mm), successful CB-based PV isolation was performed. Lowest median balloon temperature and esophageal temperature for the right superior PV were −51°C and 35.8°C, −47°C and 35°C for the right inferior PV, −51°C and 34.4°C for the left superior PV, −48°C and 34.6°C for the left inferior PV, and −54°C and 34.5°C for the left common PV, respectively. EGD performed 2±1 days post ablation demonstrated superficial thermal lesions and thermal ulcerations in 1 of 50 (2%) and 5 of 50 (10%) patients, respectively. In patients with ETLs, during ≥1 freeze cycle the endoluminal esophageal temperature measured <3.0°C. All thermal lesions were in the healing process on repeat EGD 4±2 days after initial endoscopy. Conclusions—Using the second-generation 28-mm CB, ETLs were detected in 6 of 50 (12%) patients. All ETLs were in the healing process on repeat EGD. An esophageal temperature safety cutoff may prove valuable in the prevention of ETLs and requires further evaluation.

Unexpectedly High Incidence of Stroke and Left Atrial Appendage Thrombus Formation After Electrical Isolation of the Left Atrial Appendage for the Treatment of Atrial Tachyarrhythmias

Background—Electric left atrial appendage (LAA) isolation (LAAI) may occur during catheter ablation of atrial tachyarrhythmias. Data regarding the risk of thromboembolic events and stroke after LAAI are sparse. This study evaluated the incidence of LAA thrombus formation and thromboembolic events after LAAI. Methods and Results—Fifty patients had LAAI (age=71 years; female=56%; CHA2DS2-VASc score before ablation =3 [2;3]). LAAI patients were compared with matched patients with comparable baseline characteristics who underwent atrial fibrillation ablation without LAAI (n=50). Ablation strategies in the LAAI group included pulmonary vein isolation in 50 (100%), left atrial isthmus line in 47 (94%), anterior line in 45 (90%), complex atrial fractionated potentials in 24 (48%), and roofline in 14 (28%) patients. Transesophageal echocardiography was performed during follow-up in 47/50 (94%) patients in the LAAI group and in all patients of the control group. Oral anticoagulation (OAC) independent of CHA2DS2-VASc score was strongly recommended in all patients. During a median follow-up of 6.5 (4–12) months, stroke occurred in 2 patients on OAC and transient ischemic attack in one without OAC in the LAAI group. In the remaining 47 patients, LAA thrombus was identified on transesophageal echocardiography in 10 (21%) patients (OAC=9; no OAC=1). In the control group, no LAA thrombus was detected and no stroke occurred (P<0.001). Stable sinus rhythm was maintained in 32 patients (64%) of the LAAI group after a median follow-up of 6.5 months (4–12), including 17/32 patients on antiarrhythmic drugs. Conclusions—After LAAI, an unexpectedly high incidence of LAA thrombus formation and stroke was observed despite OAC therapy.

One-year clinical outcome after pulmonary vein isolation using the novel endoscopic ablation system in patients with paroxysmal atrial fibrillation.

BACKGROUND Pulmonary vein isolation (PVI) is an established treatment option for atrial fibrillation (AF). Recently the novel endoscopic ablation system (EAS) was introduced and proved potential for successful acute PVI. OBJECTIVE This study sought to investigate the 1-year follow-up results after EAS-based PVI. METHODS A total of 40 patients (20 female, age 57 ± 9 years) with a long history (5 ± 4 years) of drug-refractory (2 ± 1 antiarrhythmic drugs) paroxysmal AF were included into our analysis. PVI was performed using exclusively the novel EAS. Follow-up included regular telephonic interviews, Holter electrocardiographic (ECG) and transtelephonic ECG recordings. A symptomatic or documented AF episode >60 seconds after a blanking period of 3 months was defined as recurrence. RESULTS A total of 155 PVs were targeted; 153 of 155 (99%) PVs were isolated successfully using exclusively the novel EAS. During a median follow-up of 402 (331 to 478; quartile 1 to quartile 3) days, 24 of 40 patients (60%) remained free of any symptomatic or documented AF episode without antiarrhythmic drugs after a single procedure. Seven patients suffering from AF recurrence underwent radiofrequency current-based Re-PVI 203 ± 102 days after the index EAS-based procedure. Left atrium to pulmonary vein reconduction was found in 17 of 25 initially isolated PVs. No PV stenosis was detected based on magnetic resonance imaging 3 months postablation. CONCLUSION Patients after EAS-based PVI due to paroxysmal AF demonstrate 1-year single-procedure success rates similar to those of other ablation techniques and ablation energies. The major determinant for AF recurrence after EAS treatment seems to be reconnection of previously isolated PVs. More patients and longer follow-up periods are mandatory before final conclusions can be drawn regarding the efficacy and safety of the EAS.

Predictive Value of Programmed Ventricular Stimulation After Catheter Ablation of Post-Infarction Ventricular Tachycardia

BACKGROUND A recent meta-analysis demonstrated a survival benefit in post-infarction patients whose ventricular tachycardia (VT) was rendered noninducible by catheter ablation. Furthermore, patients with noninducible VT had a lower VT recurrence rate than did patients whose VT remained inducible after ablation. OBJECTIVES The purpose of this multicenter cohort study was to assess whether noninducibility after VT ablation is independently associated with improved survival. METHODS Data from 1,064 patients who underwent VT ablation for post-infarction VT at seven international centers were analyzed. The ablation procedure was considered successful if no VT was inducible at the end of the procedure and unsuccessful if VT remained inducible or if programmed stimulation was not performed at the end of the ablation. RESULTS Median follow-up time was 633 days. Noninducibility was independently associated with lower mortality (adjusted hazard ratio: 0.65; 95% confidence interval: 0.53 to 0.79; p<0.001). Atrial fibrillation, diabetes, and age were other independent predictors of higher mortality. Ablation of only the clinical VT in patients who also had inducible, nonclinical VTs was not associated with improved survival. CONCLUSIONS Noninducibility after VT ablation in patients with post-infarction VT is independently associated with lower mortality during long-term follow-up.

Cryoballoon temperature predicts acute pulmonary vein isolation

BACKGROUND Cryoballoon pulmonary vein isolation (PVI) currently requires a long cryoballoon application (CBA) time of 240 to 300 seconds, thus repeated ineffective CBA prolongs procedure duration. We hypothesized that cryoballoon temperature (CBT) may be used to discriminate between effective and ineffective CBA during freezing. OBJECTIVE This study sought to evaluate CBT as a predictor of CBA efficiency. METHODS Sixty-six patients with atrial fibrillation underwent PVI using the single big (28 mm) cryoballoon technique. CBT was continuously recorded. After each CBA (300 seconds), a Lasso catheter (Biosense Webster, Inc., Diamond Bar, California) was placed into the target pulmonary vein (PV) to determine whether electrical PV disconnection was present. Only the first CBA at each PV was analyzed to avoid cumulative effects. RESULTS The CBT was lower during CBA at superior compared with inferior PVs. When individual CBAs were grouped according to successful/failed PVI, CBT was lower for those CBAs that resulted in successful PVI at all time points analyzed. To test the performance of CBT to predict failed CBA, receiver-operator curves were constructed. A minimal CBT of ≥ -42°C/ -39°C (superior/inferior PVs) predicted failed PVI with 73%/92% specificity (area under the curve 0.82/0.81); positive predictive value (PPV) 74%/74%. A minimal CBT of < -51°C was invariably associated with PVI. After 120 seconds of freezing, a CBT of ≥ -36°C/ -33°C (superior/inferior PVs) predicted failed PVI with 97%/95% specificity (area under the curve 0.82/0.76); PPV 82%/80%. CONCLUSION Balloon temperature predicts successful target PVI during cryoablation and may serve in the early identification of noneffective balloon applications.

One-year clinical outcome after pulmonary vein isolation in persistent atrial fibrillation using the second-generation 28 mm cryoballoon: a retrospective analysis

AIMS The purpose of this study was to determine efficacy of pulmonary vein isolation (PVI) using the 28 mm cryoballoon (CB) in patients with persistent atrial fibrillation (AF). Superior acute and 1-year outcome has been demonstrated following PVI, using the second-generation CB in patients with paroxysmal AF. Data on the outcome in patients with persistent AF are sparse. METHODS AND RESULTS Forty-nine patients (20 female, mean age 63 ± 10 years, mean left atrial diameter 46 ± 5 mm) with persistent AF [median AF duration since first diagnosis: 48 (20:192) months] underwent second-generation 28 mm CB-based PVI. The freeze cycle duration was set at 240 s. After successful PVI, a bonus freeze cycle of 240 s was applied in the first 11/49 (22%) patients, and no bonus freeze cycle was used in the remaining 38/49 (78%) patients. Follow-up (FU) was based on outpatient clinic visits at 3, 6, and 12 months, which included Holter electrocardiograms and telephone interviews. Recurrence was defined as an episode of symptomatic and/or documented atrial tachyarrhythmia >30 s beyond the 3-month blanking period. A total of 193 pulmonary veins (PVs) were identified and 193/193 (100%) PVs were successfully isolated. No phrenic nerve paralysis occurred. Follow-up was obtained in 49/49 (100%) patients with a mean FU duration of 416 ± 178 days. After the 3-month blanking period, antiarrhythmic medication was discontinued in 33/49 (67%) patients. Thirty-four of 49 (69%) patients remained in stable sinus rhythm. CONCLUSIONS In patients with persistent AF, use of the second-generation 28 mm CB was associated with a 69% 1-year clinical success rate.

Once Isolated, Always Isolated? Incidence and Characteristics of Pulmonary Vein Reconduction after Second-Generation Cryoballoon-Based Pulmonary Vein Isolation

Background—The second-generation cryoballoon delivers effective pulmonary vein isolation (PVI) associated with superior 1-year clinical outcome. However, data on reconduction of previously isolated PV are sparse. Methods and Results—A total of 421 patients underwent second-generation 28-mm cryoballoon-based PVI in 2 centers (St. George’s hospital and Harburg hospital, Hamburg, Germany) between June 2012 and May 2015. Sixty-six of 421 (16%) patients (39/66, 59% women; mean age, 63±10 years, mean left atrium diameter, 45±6 mm) with a history of paroxysmal (40/66, 61%) or persistent atrial fibrillation and atrial tachyarrhythmia recurrences despite previous successful second-generation 28-mm cryoballoon-based PVI were included in this analysis. During the index PVI, the standard freeze cycle duration was 240 s. After successful PVI, a bonus freeze cycle of 240 s was applied in the first 15 of 66 (23%) patients, whereas no bonus freeze cycle was applied in the remaining patients. Repeat procedures were performed after a median of 205 (131–357) days following the index ablation. Electric reconduction was assessed for all PVs, and reablation was performed using radiofrequency energy. Persistent electric isolation was noted in 178 of 258 (69%) PVs. In 17 of 66 (26%) patients, all previously targeted PVs remained isolated. A significant difference toward highest reconduction rate for the posteroinferior segment of the right inferior PV was found (P=0.0002). Conclusions—The second-generation cryoballoon ablation is associated with a high rate of persistent PVI. The posteroinferior segment of the right inferior PV showed the highest reconduction rate and seems to be a predilection site for PV reconduction.

Ventricular Arrhythmias Arising from the Left Ventricular Outflow Tract below the Aortic Sinus Cusps: Mapping and Catheter Ablation via Transseptal Approach and Electrocardiographic Characteristics

Background—Ventricular arrhythmias (VAs) originating from the anterosuperior left ventricular outflow tract (LVOT) represent a challenging location for catheter ablation. This study investigates mapping and ablation of VA from anterosuperior LVOT via a transseptal approach. Methods and Results—This study included 27 patients with symptomatic VA, of which 13 patients had previous failed ablations. LVOT endocardial 3-dimensional mapping via retrograde transaortic and antegrade transseptal approaches was performed. Previous ECG markers for procedure failure were analyzed. In all patients, earliest activation with low-amplitude potentials was identified at the anterosuperior LVOT 5.1±2.8 mm below the aortic cusp and preceded the QRS onset by 39.5±7.7 ms only via an antegrade transseptal approach using a reversed S curve. In all patients, pace mapping failed to demonstrate perfect QRS morphology match. The anatomic location was below the left coronary cusp in 16, below the left coronary cusp/right coronary cusp junction in 8, and below the right coronary cusp in 3 patients. Radiofrequency energy resulted in rapid disappearance of VAs in all patients. ECG analysis showed aVL/aVR Q-wave amplitude ratio >1.4 in 7, lead III/II R-wave amplitude ratio >1.1 in 10, and peak deflection index >0.6 in 11 patients. There were no complications or clinical VA recurrence during a mean follow-up of 8.4±2.5 months. Conclusions—The anterosuperior LVOT can be reached via a transseptal approach with a reversed S curve of the ablation catheter. The rapid effect from radiofrequency energy indicates that the VA is most likely located under the endocardium. Also, previous ECG markers for procedure failure need further investigation.