Evan Lockwood

Catheter ablation of atrial fibrillation guided by complex fractionated atrial electrogram mapping of atrial fibrillation substrate

Cardiologists and physicians have witnessed a significant change in the management of atrial fibrillation (AF): antiarrhythmic agents are no longer considered more effective than just merely using compounds that control ventricular response of the arrhythmia with anticoagulation in high-risk patients. Catheter ablation has grown into wider acceptance as an important therapeutic modality in treating tachyarrhythmias. And over the past decade, several studies have clearly established that catheter ablation of atrial fibrillation is safe and effective and is an important alternative therapeutic option to the pharmacological approach. In general, there are two approaches to AF ablation: The anatomical approach, the most popular one, relies on isolation of electrical connections of all four pulmonary veins to the left atrium with or without adjuvant ablations, i.e. additional linear ablations. The second approach is the electrogram-guided approach by mapping and targeting areas of complex fractionated atrial electrograms (CFAE) which is the main topic of this review. The myriad pathologies leading to and resulting from AF have led to many theories regarding how substrate should be defined and how to reconcile substrate ablation with trigger ablation. The identification of spatiotemporally stable areas of very low amplitude short cycle length CFAE in a sea of otherwise discrete normal amplitude and relatively longer cycle length electrograms led to ablate the CFAE as a marker of abnormal substrate. This pure substrate-based ablation strategy has resulted in remarkable success, including mortality benefit, even in high-risk patients with very long standing persistent AF. In this review, we discuss in detail the prevailing mechanisms underlying CFAE, how to map and ablate CFAE sites, correlation of CFAE areas to those of ganglionic plexi, clinical outcomes of the approach, and the role of CFAE in the hybrid approach of AF ablation using a combination of pulmonary vein isolation and targeting CFAE areas.

Does 24-hour ST-segment resolution postfibrinolysis add prognostic value to a Q wave? An ASSENT 2 electrocardiographic substudy

BACKGROUND Both ST resolution and Q-wave development postfibrinolysis provide important prognostic insights in patients with acute myocardial infarction (MI). However, the relative contributions of these 2 factors to risk assessment have not been examined prospectively. METHODS AND RESULTS ST resolution and Q development were evaluated 24 to 36 hours (24-36 h) postfibrinolysis in ASSENT-2: 13,100 out of 16,949 patients who had both baseline and 24-36 h electrocardiograms free of confounders (left bundle branch block, ventricular rhythm, reinfarction before 24-36 h electrocardiograms) were included in this analysis. Q-wave MI evolved in 10,466 patients (79.9%) and 2634 patients (20.1%) had non-Q-wave MI at 24-36 h postfibrinolysis. Mortality rates at 1-year were 7.0% for patients with Q-wave MI and 5.8% for non-Q-wave MI patients, respectively (P =.046). Patients with Q-wave MI versus those without were less likely to have complete ST-segment resolution (49.1% vs 59.1%) and more likely to have partial (37.1% vs 27.8%) or no resolution (13.8% vs 13.1%) at 24 to 36 hours postfibrinolysis (P <.001). Mortality rates at 1 year for Q-wave MI with complete, partial, and no resolution were 5.2%, 8.1%, and 10.1%, respectively (P <.001), and for non-Q-wave MI with complete, partial, and no resolution were 4.5%, 7.6%, and 8.0% (P =.003). CONCLUSION These results demonstrate the additional prognostic significance of ST-segment resolution to Q-wave development at 24 to 36 hours after fibrinolysis.

Intracardiac ablation for atrioventricular nodal reentry tachycardia using a 6 mm distal electrode cryoablation catheter: Prospective, multicenter, North American study (ICY-AVNRT STUDY)

Radiofrequency (RF) ablation is effective for slow pathway ablation, but carries a risk of inadvertent AV block requiring permanent pacing. By comparison, cryoablation with a 4‐mm distal electrode catheter has not been reported to cause permanent AV block but has been shown to be less effective than RF ablation. We sought to define the safety and efficacy of a 6‐mm distal electrode cryoablation catheter for slow pathway ablation in patients with atrioventricular nodal reentry tachycardia (AVNRT).

Esophageal perforation after radiofrequency ablation for atrial fibrillation.

A 69-year-old man underwent left atrial radiofrequency ablation for atrial fibrillation. After 10 minutes, the procedure was terminated due to pericardial tamponade secondary to perforation during mapping. Pericardiocentesis resolved the tamponade. Ablation was completed one week later, and the patient was discharged. Two days later, he presented with odynophagia. Computed tomography demonstrated small bilateral pleural effusions. He was judged to be stable and was discharged again, but returned 2 days later with chest pain. He was found to have esophageal perforation with empyema, which was repaired using a muscle patch and esophageal stenting, successfully treating the lesion with minimal morbidity.

WHAT FACTORS INFLUENCE THE CHOICE OF APIXABAN, RIVAROXABAN, OR DABIGATRAN FOR STROKE PREVENTION AMONG ATRIAL FIBRILLATION PATIENTS IN REAL-WORLD CLINICAL PRACTICE? INSIGHTS FROM THE PROSPECTIVE SPRINT-AF REGISTRY

Non-vitamin K oral anticoagulants (NOAC) are commonly prescribed to prevent stroke for patients with atrial fibrillation (AF). We sought to assess factors which might influence the selection of a particular NOAC agent in real-world clinical practice. The Stroke Prevention and Rhythm INTerventions

DISAGREEMENT BETWEEN PHYSICIAN-REPORTED AND SCORING SYSTEM-BASED STROKE AND BLEEDING RISKS IN PATIENTS WITH ATRIAL FIBRILLATION: INSIGHTS FROM THE STROKE PREVENTION AND RHYTHM INTERVENTIONS IN ATRIAL FIBRILLATION (SPRINT-AF) REGISTRY

 Presence of prosthetic heart valve or significant valvular heart disease (defined as: mitral stenosis, moderate or severe aortic stenosis, or severe mitral regurgitation).  Active malignancy.  Life expectancy < 12 months.  An existing clinical indication for OAC treatment other than AF (e.g. venous thromboembolism, hypercoagulable disorders)  Prior participation in an OAC randomized trial. Statistical Analysis Plan:  Agreement between physician-reported and score-derived risks was reported by the weighted kappa with 95% confidence intervals (CI).  Weighted kappa values of 0.01-0.20, 0.21-0.40, 0.41-0.60, 0.61-0.80, and 0.81-0.99 represent slight, fair, moderate, good, and excellent agreement, respectively.  The weighted kappa was used since the categorization of bleeding and stroke risk consisted of 3 levels (low, moderate, high).