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Time-Domain T-Wave Alternans and Brugada Syndrome Aims T-wave alternans (TWA) is an indicator of vulnerability to ventricular arrhythmias and is useful for predicting sudden cardiac death (SCD) in patients with various structural heart diseases. We evaluated whether high levels of time-domain TWA on ambulatory ECG (AECG) are associated with a history of ventricular fibrillation (VF) in Brugada syndrome (BrS) patients. Methods and Results We examined the associations among VF history, family history of SCD, spontaneous type 1 electrocardiogram (ECG), late potentials, VF induction by programmed electrical stimulation, and TWA in 45 BrS patients (44 males; mean age, 45 ± 15 years). TWA analyzed from 24-h AECG recordings using the modified moving average method was positive in 13 of 43 patients (30%). Patients with a history of VF had a significantly higher incidence of a positive TWA test (82% vs. 13%; P < 0.001) and spontaneous type 1 ECG (92% vs. 38%; P = 0.007) than those without VF history. Multivariate analysis indicated that positive TWA (OR 7.217; 95% CI 2.503–35.504; P = 0.002) and spontaneous type 1 ECG (OR 5.530; 95% CI 1.651–34.337; P = 0.020) were closely associated with VF history. Spontaneous type 1 ECG had high sensitivity (92%) but low specificity (63%). Positive TWA was a reliable marker with high sensitivity and specificity (82% and 88%, respectively). Conclusion Elevated time-domain TWA on AECG confirms arrhythmia risk in symptomatic BrS patients without the need for provocative stimuli.

Variable Strategies for CTI Ablation Objectives This study aimed to investigate the anatomical characteristics complicating cavotricuspid isthmus (CTI) ablation and the effectiveness of various procedural strategies. Methods and Results This study included 446 consecutive patients (362 males; mean age 60.5 ± 10.4 years) in whom CTI ablation was performed. A total of 80 consecutive patients were evaluated in a preliminary study. The anatomy of the CTI was evaluated by multidetector row-computed tomography (MDCT) prior to the procedure. A multivariate logistic regression analysis revealed that the angle and mean wall thickness of the CTI, a concave CTI morphology, and a prominent Eustachian ridge, were associated with a difficult CTI ablation (P < 0.01). In the main study, 366 consecutive patients were divided into 2 groups: a modulation group (catheter inversion technique for a concave aspect, prominent Eustachian ridge, and steep angle of the CTI or increased output for a thicker CTI) and nonmodulation group (conventional strategy). The duration and total amount of radiofrequency energy delivered were significantly shorter and smaller in the modulation group than those in the nonmodulation group (162.2 ± 153.5 vs 222.7 ± 191.9 seconds, P < 0.01, and 16,962.4 ± 11,545.6 vs 24,908.5 ± 22,804.2 J, P < 0.01, respectively). The recurrence rate of type 1 atrial flutter after the CTI ablation in the nonmodulation group was significantly higher than that in the modulation group (6.3 vs 1.7%, P = 0.02). Conclusion Changing the procedural strategies by adaptating them to the anatomical characteristics improved the outcomes of the CTI ablation.

Objectives: We noted a low-velocity signal opposite to the early diastolic transmitral flow (E) by pulsed Doppler echocardiography. The purpose of this study was to examine the origin and significance of this signal. Background: The background of the signal remains uncertain. Methods: We studied 59 adult patients (34 men and 25 women; mean age, 58.9 [20.2] years) without mitral valve heart disease. Mitral E-wave velocity and the signal (EW) opposite the E-wave were measured by pulsed Doppler echocardiography. Early diastolic mitral valve ring motion velocity (Ea) was measured by pulsed tissue Doppler echocardiography. Pulmonary capillary wedge pressure (PCWP) was measured by a Swan-Ganz catheter in 34 of the 59 patients. Results: A blue signal was observed during early diastole from the mitral valve ring to the mitral orifice areas by color tissue Doppler echocardiography. The velocity profile method revealed the same direction and time between peak Ea and EW. Peak EW positively correlated with Ea (r = 0.67, P 12 mmHg than in patients with PCWP ≤ 12 mmHg (5.6 [1.3] cm/s vs. 4.3 [0.9] cm/s, P < 0.01). Conclusions: EW may be related to mitral valve ring motion, and the E/EW ratio may be a noninvasive simple parameter for assessing left ventricular filling pressure. (Echocardiography 2011;28:606-611)

Clinical manifestations of arrhythmogenic right ventricular cardiomyopathy (ARVC) are variable, and in some cases, ventricular fibrillation (VF) represents the first manifestation. In order to aid in the prevention of sudden cardiac death due to ARVC, we examined the clinical presentations of ARVC patients whose first sign was VF or another manifestation. Fifteen patients (male/female 7/8, mean age 47 years, ge of onset 41 years) diagnosed as having ARVC using the updated 2010 Task Force Criteria were included. The earliest symptoms were VF in 3 patients; ventricular tachycardia in 6 patients; heart failure in 3 patients; and ECG abnormality, family history, and premature ventricular contractions in 3 patients. We investigated clinical data based on 12-lead ECG, signal-averaged ECG (SAECG), Holter ECG, echocardiography, right ventricular biopsy, multidetector computed tomography (MDCT), magnetic resonance imaging, substrate mapping using an electroanatomical mapping system, and 123I-metaiodobenzylguanidine scintigraphy for all subjects. Repolarization abnormalities (inverted T waves in right precordial leads) and depolarization abnormalities (late potentials by SAECG) were observed in all patients. We made a remarkable MDCT observation in all patients whose earliest symptom was VF: trabeculae distal to the RV moderator band showed a netlike appearance. The other parameters were similar in patients with and without VF. This particular netlike appearance of RV may be a pathogenesis of VF in ARVC.

Background: Indication of ablation has been expanded to include chronic atrial fibrillation (CAF) for enabling high degree of sinus rhythm maintenance. We have encountered patients undergoing pacemaker implantation, in whom sick sinus syndrome became clinically evident after ablation. The study aims to investigate whether underling sinus node dysfunction (SND) during CAF can be predicted before deciding the indication for ablation. Methods and Results: Sixty consecutive patients with CAF who underwent ablation between January to December 2010 were enrolled in the study. Nocturnal polysomnography as well as echocardiography was performed for all patients before ablation. We used the double Lasso catheter and electro anatomical mapping guided extensive encircling pulmonary vein isolation (EEPVI). We performed electrophysiological studies after EEPVI, and SND was defined as corrected SN recovery time of ≥550 ms. SND was detected in 26 (43%) patients (SND group); the other patients showed normal sinus node function (NSN group). The apnea/hypopnea index (AHI) was significantly greater in the SND group than in the NSN group (25.7±13 vs 15.8±10, P=0.0022). On multivariate analysis, sleep apnea syndrome (SAS) was an independent predictor of SND after ablation for CAF. Conclusion: This study suggested that underlying SND in CAF patients can be predicted by evaluating SAS before ablation.