Simon Sporton

The impact of CT image integration into an electroanatomic mapping system on clinical outcomes of catheter ablation of atrial fibrillation.

Background: A detailed appreciation of left atrial/pulmonary vein (LA/PV) anatomy may be important in improving the safety and success of catheter ablation (CA) for atrial fibrillation (AF).

Validation of Three-Dimensional Cardiac Image Integration: Use of Integrated CT Image into Electroanatomic Mapping System to Perform Catheter Ablation of Atrial Fibrillation

Introduction: Accurate visualization of the complex left atrial (LA) anatomy and the location of an ablation catheter within the chamber is important in the success and safety of ablation for atrial fibrillation (AF). We describe the integration of CT into an electroanatomic mapping (EAM) system and its validation in patients undergoing catheter ablation for AF.

Maintenance of sinus rhythm with an ablation strategy in patients with atrial fibrillation is associated with a lower risk of stroke and death

Objective To investigate whether catheter ablation of atrial fibrillation (AF) reduces stroke rate or mortality. Methods An international multicentre registry was compiled from seven centres in the UK and Australia for consecutive patients undergoing catheter ablation of AF. Long-term outcomes were compared with (1) a cohort with AF treated medically in the Euro Heart Survey, and (2) a hypothetical cohort without AF, age and gender matched to the general population. Analysis of stroke and death was carried out after the first procedure (including peri-procedural events) regardless of success, on an intention-to-treat basis. Results 1273 patients, aged 58±11 years, 56% paroxysmal AF, CHADS2 score 0.7±0.9, underwent 1.8±0.9 procedures. Major complications occurred in 5.4% of procedures, including stroke/TIA in 0.7%. Freedom from AF following the last procedure was 85% (76% off antiarrhythmic drugs) for paroxysmal AF, and 72% (60% off antiarrhythmic drugs) for persistent AF. During 3.1 (1.0–9.6) years from the first procedure, freedom from AF predicted stroke-free survival on multivariate analysis (HR=0.30, CI 0.16 to 0.55, p<0.001). Rates of stroke and death were significantly lower in this cohort (both 0.5% per patient-year) compared with those treated medically in the Euro Heart Survey (2.8% and 5.3%, respectively; p<0.0001). Rates of stroke and death were no different from those of the general population (0.4% and 1.0%, respectively). Conclusion Restoration of sinus rhythm by catheter ablation of AF is associated with lower rates of stroke and death compared with patients treated medically.

A Randomized Controlled Trial of Catheter Ablation Versus Medical Treatment of Atrial Fibrillation in Heart Failure (The CAMTAF Trial)

Background—Restoring sinus rhythm in patients with heart failure (HF) and atrial fibrillation (AF) may improve left ventricular (LV) function and HF symptoms. We sought to compare the effect of a catheter ablation strategy with that of a medical rate control strategy in patients with persistent AF and HF. Methods and Results—Patients with persistent AF, symptomatic HF, and LV ejection fraction <50% were randomized to catheter ablation or medical rate control. The primary end-point was the difference between groups in LV ejection fraction at 6 months. Baseline LV ejection fraction was 32±8% in the ablation group and 34±12% in the medical group. Twenty-six patients underwent catheter ablation, and 24 patients were rate controlled. Freedom from AF was achieved in 21/26 (81%) at 6 months off antiarrhythmic drugs. LV ejection fraction at 6 months in the ablation group was 40±12% compared with 31±13% in the rate control group (P=0.015). Ablation was associated with better peak oxygen consumption (22±6 versus 18±6 mL/kg per minute; P=0.014) and Minnesota living with HF questionnaire score (24±22 versus 47±22; P=0.001) compared with rate control. Conclusions—Catheter ablation is effective in restoring sinus rhythm in selected patients with persistent AF and HF, and can improve LV function, functional capacity, and HF symptoms compared with rate control. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT01411371

Electroanatomic Versus Fluoroscopic Mapping for Catheter Ablation Procedures

Introduction: The aim of this prospective randomized study was to compare the routine use of electroanatomic imaging (CARTO) with that of conventional fluoroscopically guided activation mapping (conventional) in an unselected population referred for catheter ablation. We sought to compare the two approaches with respect to procedure outcome and duration, radiation exposure, and cost.

The impact of image integration on catheter ablation of atrial fibrillation using electroanatomic mapping: a prospective randomized study

AIMS A detailed appreciation of the left atrial/pulmonary venous (LA/PV) anatomy may be important in improving the safety and success of catheter ablation for AF. The aim of this randomized study was to determine the impact of computed tomographic (CT) integration into an electroanatomic mapping (EAM) system on clinical outcome in patients undergoing catheter ablation for atrial fibrillation (AF). METHODS AND RESULTS Eighty patients with AF were randomized to undergo first-time wide encirclement of ipsilateral PV pairs using EAM alone (40 patients) or with CT (40 patients, Cartomerge). Wide encirclement of the pulmonary veins was performed using irrigated radiofrequency ablation with the electrophysiological endpoint of electrical isolation (EI). The primary endpoint was single-procedure success at 6 month follow up. Acute and long-term procedural outcomes were also determined. There was no significant difference in single procedure success between EAM (56%) and cavotricuspid isthmus image (CTI) (50%) groups (P = 0.9). Acute procedural outcomes (EI, PV reconnection, sinus rhythm restored by ablation in persistent AF), fluoroscopy, and procedure durations (EI of right PVs, EI of left PVs, total) did not differ significantly between EAM and CTI groups. CONCLUSION Image integration to guide catheter ablation for AF did not significantly improve the clinical outcome. Achieving PV EI is the critical determinant of procedural success rather than the mapping tools used to achieve it.

Acute and Chronic Pulmonary Vein Reconnection after Atrial Fibrillation Ablation : A Prospective Characterization of Anatomical Sites

Background: Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR.

Electrophysiologic and Anatomic Characterization of Sites Resistant to Electrical Isolation During Circumferential Pulmonary Vein Ablation for Atrial Fibrillation: A Prospective Study

Background: Catheter ablation (CA) by wide encirclement of pulmonary veins (WEPV) restores sinus rhythm in up to 95%. Complex PV–left atrial (LA) connections make achieving electrical isolation (EI) challenging. We examined anatomical and technical features associated with resistance to EI during WEPV in a prospective study.

Comparison of Noncontact and Electroanatomic Mapping to Identify Scar and Arrhythmia Late After the Fontan Procedure

Background— The right atrium late after the Fontan procedure is characterized by multiple complex arrhythmia circuits. We performed simultaneous electroanatomic and noncontact mapping to assess the accuracy of both systems to identify scar and arrhythmia. Methods and Results— Mapping was performed in 26 patients aged 26.8±8.9 years, 18.7±4.4 years after Fontan surgery. The area and site of abnormal endocardium defined by electroanatomic mapping (bipolar contact electrogram <0.5 mV) were compared with those defined by noncontact mapping during sinus rhythm and by dynamic substrate mapping. Contact and reconstructed unipolar electrograms at a known distance from the multielectrode array, recorded by the noncontact system simultaneously at 452 endocardial sites, were compared for morphological cross correlation, timing difference, and amplitude. Mapping of arrhythmias was performed with both systems when possible. The median patient abnormal endocardium as defined by electroanatomic mapping covered 38.0% (range 16.7% to 97.8%) of the right atrial surface area, as opposed to 60.9% (range 21.3% to 98.5%) defined by noncontact mapping during sinus rhythm and 11.9% (range 0.4% to 67.3%) by dynamic substrate mapping. A significant decrease in electrogram cross correlation (P=0.003), timing (P=0.012), and amplitude (P=0.003) of reconstructed electrograms, but not of contact electrograms (P=0.742), was seen at endocardial sites >40 mm from the multielectrode array. Successful arrhythmia mapping by electroanatomic versus noncontact mapping was superior in 15 patients (58%), the same in 6 (23%), and inferior in 5 (19%; P=0.044). Conclusions— Electroanatomic mapping is the superior modality for arrhythmia mapping late after the Fontan procedure. Noncontact mapping is limited by a significant reduction in reconstructed electrogram correlation, timing, and amplitude >40 mm from the multielectrode array and cannot accurately define areas of scar and low-voltage endocardium.

Long-term efficacy of catheter ablation for atrial fibrillation: impact of additional targeting of fractionated electrograms

Objectives To investigate long-term efficacy of catheter ablation for atrial fibrillation (AF) and the impact of ablating complex or fractionated electrograms (CFEs) in addition to pulmonary vein isolation and linear lesions in persistent AF (PeAF). Methods Consecutive cases from 2002–2007 were analysed. All the patients underwent a wide-area circumferential ablation with confirmation of electrical isolation. For PeAF, linear lesions were added, with additional targeting of CFE from 2005. Data were collected in a prospective database. Attempts were made to contact all patients for follow-up. Results 285 patients underwent 530 procedures. The mean (SD) age was 57 (11) years, 75% were male, 20% had structural heart disease and 53% had paroxysmal AF (PAF). The mean number of procedures was 1.9 per patient (1.7 for PAF and 2.0 for PeAF). Procedural complications included stroke or transient ischemic attack in 0.6% and pericardial effusion requiring drainage in 1.7%. During 2.7 years (0.2 to 7.4 years) of follow-up from the last procedure, there were seven deaths (unrelated to their ablation or AF) and three strokes or transient ischemic attack (0.3% per year). Freedom from AF/atrial tachyarrhythmia was 86% for PAF and 68% for PeAF. Late recurrence was 3 per 100 years of follow-up after >3 years. The Kaplan–Meier analysis showed that CFE ablation improved the outcome for PeAF after the first cluster of procedures (p=0.049), with a trend towards improved final outcome (p=0.130). Conclusions Long-term freedom from AF is achievable in most patients with PAF and PeAF with low rates of late recurrence. Additional targeting of CFE improves outcome for PeAF. Late adverse events including stroke are few.