Michiharu Senga

Silent Cerebral Ischemic Lesions After Catheter Ablation of Atrial Fibrillation in Patients on 5 Types of Periprocedural Oral Anticoagulation - Predictors of Diffusion-Weighted Imaging-Positive Lesions and Follow-up Magnetic Resonance Imaging.

BACKGROUND The aim of this study was to identify the predictors of silent cerebral ischemic lesions (SCIL) after catheter ablation of atrial fibrillation (AF) and to determine whether SCIL develop into cerebral infarcts in patients with 5 types of oral anticoagulants (OAC). METHODSANDRESULTS We retrospectively studied 286 consecutive patients (median, 67 years; 208 male; paroxysmal/persistent/long-standing persistent AF [LSP-AF], 147/90/49) who received periprocedural OAC and underwent MRI after the procedure. Warfarin (n=46) was continued, while dabigatran (n=47), rivaroxaban (n=89), apixaban (n=87), and edoxaban (n=17) were discontinued on the day of the procedure. I.v. heparin was infused to maintain an activated clotting time of 300-350 s during the procedure. Fifty-eight SCIL in 40 patients (14.0%) were identified on diffusion-weighted MRI. On multivariate logistic analysis, LSP-AF and dabigatran use were significant positive predictors of SCIL (OR, 2.912 and 2.287; P=0.006 and 0.042, respectively). Among 34 patients with 49 SCIL undergoing follow-up MRI, 45 (91.8%) of the lesions disappeared and 4 lesions developed into chronic cerebral infarcts. The SCIL with development into infarcts had a larger lesion diameter than those without (median, 6.55 mm vs. 4.2 mm; P=0.002). CONCLUSIONS LSP-AF and dabigatran use were independent risk factors for post-ablation SCIL in patients with uninterrupted warfarin and interrupted non-vitamin K antagonist OAC, but the majority of SCIL disappeared.

Efficacy of linear block at the left atrial roof in atrial fibrillation.

BACKGROUND After extensive encircling of ipsilateral pulmonary vein isolation (EEPVI) for atrial fibrillation (AF), we sometimes observe AF recurrence, or the occurrence of atrial tachycardia originating from the left atrium. This study examined the efficacy of additional linear ablation at the left atrial (LA) roof in combination with EEPVI to prevent arrhythmia recurrences. METHODS This study included 104 patients with drug-refractory AF (75 with paroxysmal, 29 with persistent). The patients in Group A (n=70) underwent EEPVI treatment alone, and the patients in Group B (n=34) underwent linear ablation at the LA roof in addition to EEPVI treatment. At 1, 3, 6, and 12 months after ablation, patients underwent clinical review and 24-h ambulatory electrocardiogram monitoring to identify asymptomatic arrhythmias. Follow-up included daily trans-telephonic event monitoring, transmitted irrespective of the patients symptoms. RESULTS At 12 months, 57% of Group A and 79% of Group B were free of arrhythmias (p<0.05). Cox regression analysis demonstrated that among the variables of age, sex, duration of AF, types of AF (paroxysmal or persistent), LA size, ejection fraction, existence of hypertension, ischemic heart disease, valvular heart disease, history of stroke, and the ablation technique, only the ablation technique of the linear block at the LA roof was the independent predictor of arrhythmia-free recovery after ablation. CONCLUSIONS EEPVI in combination with the linear ablation at the LA roof is associated with an improved clinical outcome compared with EEPVI alone.

The Utility of Transtelephonic Electrocardiograms for Detecting Arrhythmia Recurrences after Radiofrequency Catheter Ablation for Atrial Fibrillation

Background: Extensive encircling pulmonary vein isolation (EEPVI) is effective for atrial fibrillation (AF). However, the definition of success following ablation is commonly based on the lack of symptoms. The purpose of this study was to determine the incidence of recurrences of AF by daily transtelephonic electrocardiogram (T‐ECG), as compared with Holter ECG, after ablation of AF.

Echocardiographic Assessment of Cardiac Structural and Functional Abnormalities in Patients With End-Stage Renal Disease Receiving Chronic Hemodialysis

BACKGROUND The aim of this study was to assess the echocardiographic characteristics of chronic hemodialysis (HD) patients with end-stage renal disease (ESRD) in a multicenter prospective cohort study.Methods and Results:Three hundred and fifteen patients with ESRD (67.9±10.6 years, 47.6% male) on chronic HD for ≥1 year were examined on transthoracic echocardiography, including Doppler-derived aortic valve area (AVA) measurement. Only 11.5% and 3.4% of all patients had normal left ventricular (LV) geometry and normal LV filling pattern, respectively. The majority of patients had aortic and mitral valvular calcification, and approximately 50% of all 315 patients had aortic valve narrowing with AVA <2.0 cm2. Patients were divided into 3 groups according to AVA index tertile: group 1, highest tertile; group 2, middle tertile; and group 3, lowest tertile. Group 3 was older, had a greater cardiothoracic ratio on chest X-ray, higher plasma brain natriuretic peptide and total LV afterload, and lower stroke volume index than the other 2 groups. Age and intact parathyroid hormone (PTH) level were independently associated with low AVA index. CONCLUSIONS Patients with ESRD on chronic HD have a high prevalence of cardiac structural and functional abnormalities including calcified aortic sclerosis. High age and PTH were associated with aortic valve narrowing in these patients.

Catheter Ablation of a Complex Atrial Tachycardia after Surgical Repair of Tetralogy of Fallot Guided by Combined Noncontact and Contact Mapping

A 34‐year‐old man with a surgically repaired Tetralogy of Fallot complained of palpitation, fatigue, and presyncope. A 12‐lead ECG showed atrial tachycardia with a cycle length of 250 ms and a P wave morphology positive in leads II, III and aVF, and negative in lead V1. Although the EnSite system (version 6.OJ) made use of noncontact mapping to delineate the counterclockwise reentry around the crista tenninalis, it was difficult to rule out the incisional atrial reentry because the location of the surgical incision was far from the multi‐electrode array. Since the bipolar contact mapping of the EnSite system revealed the location of the atriotomy incision, entrainment mapping during the tachycardia demonstrated the critical reentry circuit around the crista terminalis. Radiofrequency ablation targeting the critical isthmus from the lower position of the crista terminalis to the posterior dense scar which was continuous with the inferior vena cava, and to the atriotomy scar, eliminated the tachycardia.

Adenosine Triphosphate-sensitive Micro-reentrant Atrial Tachycardia Originating from the Crista Terminalis in a Patient with Chronic Renal Failure due to Thrombotic Thrombocytopenic Purpura

A 57‐year‐old woman with chronic renal failure due to the thrombotic thrombocytopenic purpura complained of palpitation. A 12‐lead ECG showed supraventricular tachycardia with a cycle length of 375 ms. During the electrophysiological study, a tachycardia with a cycle length of 375 ms was reproducibly induced and terminated by atrial extrastimulation. The tachycardia exhibited an inverse relationship between the coupling interval of extrastimulus initiating the tachycardia, and the first postpacing return cycle, as well as an increasing pattern of resetting the tachycardia with an atrial extrastimulus. Ventricular burst pacing during tachycardia produced AV dissociation. Intravenous injections of a low dose (4 mg) of adenosine triphosphate (ATP) terminated the tachycardia without a preceding atrio‐His bundle block. The tachycardia was diagnosed as an ATP‐sensitive micro‐reentrant atrial tachycardia. Real‐time endocardial activation mapping using an electroanatomical mapping system revealed that the earliest activation site of the tachycardia was located at the midlateral portion of the crista terminalis. The tachycardia was abolished by focal ablation targeting the earliest activation site during tachycardia. This is the first reported case of an ATP‐sensitive micro‐reentrant atrial tachycardia associated with thrombotic thrombocytopenic purpura.