Hiroshi Ogi

Left atrial thickness under the catheter ablation lines in patients with paroxysmal atrial fibrillation: insights from 64-slice multidetector computed tomography

A detailed understanding of the left atrial (LA) anatomy in patients with atrial fibrillation (AF) would improve the safety and efficacy of the radiofrequency catheter ablation. The objective of this study was to examine the myocardial thickness under the lines of the circumferential pulmonary vein isolation (CPVI) using 64-slice multidetector computed tomography (MDCT). Fifty-four consecutive symptomatic drug-refractory paroxysmal AF patients (45 men, age 61 ± 12 years) who underwent a primary CPVI guided by a three-dimensional electroanatomic mapping system (Carto XP; Biosense-Webster, Diamond Bar, CA, USA) with CT integration (Cartomerge; Biosense-Webster) were enrolled. Using MDCT, we examined the myocardial thickness of the LA and pulmonary vein (PV) regions in all patients. An analysis of the measurements by the MDCT revealed that the LA wall was thickest in the left lateral ridge (LLR; 4.42 ± 1.28 mm) and thinnest in the left inferior pulmonary vein wall (1.68 ± 0.27 mm). On the other hand, the thickness of the posterior wall in the cases with contact between the esophagus and left PV antrum was 1.79 ± 0.22 mm (n = 30). After the primary CPVI, the freedom from AF without any drugs during a 1-year follow-up period was 78 % (n = 42). According to the multivariate analysis, the thickness of the LLR was an independent positive predictor of an AF recurrence (P = 0.041). The structure of the left atrium and PVs exhibited a variety of myocardial thicknesses in the different regions. Of those, only the measurement of the LLR thickness was associated with an AF recurrence.

A spontaneous Type 1 electrocardiogram pattern in lead V2 is an independent predictor of ventricular fibrillation in Brugada syndrome.

AIM Risk stratification for Brugada syndrome remains controversial. We investigated the relationships between episodes of ventricular fibrillation (VF) and various clinical, electrocardiographic, electrophysiologic, and genetic parameters both retrospectively and prospectively. METHODS AND RESULTS Fifty-two patients with Brugada syndrome (49 men, average age 42 +/- 3 years) were studied. In the Brugada patients with a VF history, the frequency of a spontaneous Type 1 electrocardiogram (ECG) pattern in lead V2 was significantly higher and the STJ amplitude in the V1 and V2 leads was also higher than in those without a VF history. Multivariate analyses revealed that the spontaneous Type 1 ECG pattern in lead V2 (but not lead V1) was the only independent predictor of a VF history. During a mean follow-up period of 39 +/- 4 months, 38.8% of the patients with a VF history and 2.9% of those without experienced an appropriate implantable cardioverter-defibrillation owing to VF. A multivariate analysis using a Coxs proportional hazard model showed that a VF history and spontaneous Type 1 ECG pattern in lead V2 were independent predictors of subsequent VF events. CONCLUSION A spontaneous Type 1 Brugada ECG pattern in lead V2 (but not lead V1) was both a prospective and retrospective independent predictor of VF episodes in Brugada syndrome.

Variable procedural strategies adapted to anatomical characteristics in catheter ablation of the cavotricuspid isthmus using a preoperative multidetector computed tomography analysis

This study aimed to investigate the anatomical characteristics complicating cavotricuspid isthmus (CTI) ablation and the effectiveness of various procedural strategies.

Non‐SCN5A Related Brugada Syndromes: Verification of Normal Splicing and Trafficking of SCN5A Without Exonic Mutations

Recently, it has been reported that under 20% of Brugada syndrome cases are linked to SCN5A mutations. The purpose of this study was to clarify whether abnormalities other than exonic mutations, such as splicing disorders, decreased mRNA expression levels, or membrane transport abnormalities of SCN5A, play a role in the pathogenesis of Brugada syndrome.

Disopyramide for Transient High-degree Atrioventricular Block in a Young Patient with a history of Syncope

Although high-degree atrioventricular (AV) block in patients with a history of syncope usually requires pacemaker implantation, therapeutic strategies should also be considered. A 35-year-old man presented with complaints of palpitations, nausea and dysgeusia. Since aged 30, the patient had experienced three episodes of syncope. Holter monitoring showed transient high-degree AV block (up to 5:4 block) associated with nausea, eructation and dysgeusia irrelevant to posture as well as ventricular ectopic beats with palpitation. A head-up tilt test revealed neurally mediated vasodepression but electrophysiological study showed no abnormalities. These results indicated that his transient high-degree AV block was functional, and syncope would have been because of neurally mediated vasodepression, not bradycardia. After administration of disopyramide at 300 mg daily, the symptoms subsided and ventricular ectopic beats and AV block disappeared. He has been well for 20 months.

Increased Urinary Liver-Type Fatty Acid–Binding Protein Level Predicts Worsening Renal Function in Patients With Acute Heart Failure

BACKGROUND Urinary liver-type fatty acid-binding protein (L-FABP) is a potential biomarker for acute kidney injury, and it in turn increases cardiovascular mortality. We tested whether the urinary L-FABP level predicted short- and mid-term outcomes in patients with acute heart failure. METHODS AND RESULTS We enrolled consecutive patients with acute heart failure, and measured their urinary L-FABP levels before acute treatment. Worsening renal function (WRF), defined as both an absolute increase in the serum creatinine level of ≥0.3mg/dL and a ≥25% relative increase in its level from baseline, occurred in 37 (26.8%) of 138 patients. Patients with a urinary L-FABP level above the upper normal limit (8.4 µg/g creatinine) (n = 49; 35.5%) were more likely than those with a urinary L-FABP level within normal limits (n = 89; 64.5%) to develop WRF (n = 26 [53.1%] vs n = 11 [12.4%]; P < .001). A urinary L-FABP level above the upper limit was independently associated with WRF (hazard ratio 1.8; P = .01). During 1 year of follow-up, 12 patients (8.7%) died, and urinary L-FABP level had no association with all-cause mortality. There was, however, a tendency toward a higher readmission rate in patients with a urinary L-FABP level above the upper normal limit who survived the index hospitalization (n = 46) than in those without an abnormal L-FABP level (n = 88; n = 13 [28.3%] vs n = 13 [14.8%]; log-rank P = .06). CONCLUSIONS Increased urinary L-FABP level before treatment may predict WRF in patients with acute heart failure. Further investigation is warranted for its predictive ability of adverse outcomes.

Postural change-dependent T-wave oversensing resulting in the administration of inappropriate shocks

A 68‐year‐old man with dilated cardiomyopathy (left ventricular ejection fraction, 15%) and nonsustained ventricular tachycardia received an implantable cardioverter defibrillator. Even though his cardiac status had greatly improved 2 years later after β‐blocker therapy, he experienced 2 episodes of sudden shock when he was squatting in a bathroom without any preceding symptoms. His serum electrolyte and plasma glucose levels were normal. Interrogation of the device revealed that the shock was caused by sinus tachycardia and T‐wave oversensing. A number of episodes of nonsustained ventricular tachycardia due to T‐wave oversensing was also recorded. Follow‐up interrogation of the device with the patient in the supine position could not reproduce the T‐wave oversensing. We were able to elicit T‐wave oversensing only after reproduction of the patients clinical situation using isoproterenol and postural changes (i.e., sinus tachycardia and squatting). This case suggests that sudden increases in nonsustained ventricular tachycardia events may be caused by T‐wave oversensing, and postural changes should be taken into consideration in such situations.

Ablation of Idiopathic Ventricular Tachycardia with a Left Bundle-Branch Block Morphology Originating from the Pulmonary Artery

We successfully performed radiofrequency catheter ablation (RFCA) in 2 cases involving patients with idiopathic ventricular tachycardias (VTs) and premature ventricular contractions (PVCs) originating from the pulmonary artery (PA). The QRS morphology of the VTs and PVCs in the two cases exhibited a left bundle‐branch block (LBBB) morphology with an inferior axis. Activation and pace mappings were performed in the right ventricular outflow tract (RVOT) and above the pulmonary valve to determine the origin of the VTs and PVCs. In both cases, the earliest ventricular activation was recorded in the PA above the pulmonary valve. Applications of radiofrequency current at those sites in the PA resulted in the elimination and noninducibility of the VT and PVC. During the follow‐up, the VT or PVC did not recur without any antiarrhythmic drug administration.