Kee-Joon Choi

Mode of onset of ventricular fibrillation in patients with early repolarization pattern vs. Brugada syndrome

AIMSnThe aim of the present study was to identify specific electrocardiogram (ECG) features that predict the development of multiple episodes of ventricular fibrillation (VF) in patients with an early repolarization (ER) pattern and to compare the mode of VF initiation with that observed in typical cases of Brugada syndrome (BrS).nnnMETHODS AND RESULTSnThe mode of the onset and the coupling intervals of the premature ventricular contractions (PVCs) initiating VF episodes were analysed in patients with BrS (n = 8) or ER who experienced sudden cardiac death/syncope or repeated appropriate implantable cardioverter defibrillator shocks. Among the 11 patients with ER, 5 presented with electrical storm (ES, four or more recurrent VF episodes/day). The five ES patients displayed a dramatic but very transient accentuation of J waves across the precordial and limb leads prior to the development of ES. Ventricular fibrillation episodes were more commonly initiated by PVCs with a short-long-short (SLS) sequence in ER (42/58, 72.4%) vs. BrS patients (13/86, 15.1%, P < 0.01). Coupling intervals were significantly shorter in the ER group compared with those with BrS [328 (320, 340) ms vs. 395 (350, 404) ms, P < 0.01].nnnCONCLUSIONnOur study provides additional evidence in support of the hypothesis that ER pattern in the ECG is not always benign. Transient augmentation of global J waves may be indicative of a highly arrhythmogenic substrate heralding multiple episodes of VF in patients with ER pattern. Ventricular tachycardia/VF initiation is more commonly associated with an SLS sequence, and PVCs display a shorter coupling interval in patients with ER pattern compared with those with BrS.

Right Phrenic Nerve Injury Following Electrical Disconnection of the Right Superior Pulmonary Vein

This report describes a case of transient paresis of the right diaphragm following the transcatheter radiofrequency ablation for the electrical disconnection of pulmonary veins, which recovered completely during the observational period in a 61‐year‐old woman with paroxysmal atrial fibrillation. For electrical disconnection of pulmonary veins, careful preventive measures for phrenic nerve damage are required.

Diagnostic approach and treatment strategy in tachycardia-induced cardiomyopathy.

Due to the absence of differential guidelines for heart failure with tachyarrhythmia, it is difficult to diagnose tachycardia‐induced cardiomyopathy (TIC) at the initial visit. Furthermore, clinical outcomes of rate versus rhythm control in TIC are unclear.

Left atrionodal connections in typical and atypical atrioventricular nodal reentrant tachycardias: activation sequence in the coronary sinus and results of radiofrequency catheter ablation.

Introduction: The presence of atrionodal connections and coronary sinus (CS) breakthrough in atrioventricular nodal reentrant tachycardia (AVNRT) has been suggested. However, the incidence, anatomic relationship with reentrant circuit, and results of catheter ablation are unknown.

Prognosis of Variant Angina Manifesting as Aborted Sudden Cardiac Death

BACKGROUNDnThe long-term prognosis of patients with variant angina presenting with aborted sudden cardiac death (ASCD) is unknown.nnnOBJECTIVESnThe purpose of this study was to evaluate the long-term mortality and ventricular tachyarrhythmic events of variant angina with and without ASCD.nnnMETHODSnBetween March 1996 and September 2014, 188 patients with variant angina with ASCD and 1,844 patients with variant angina without ASCD were retrospectively enrolled from 13 heart centers in South Korea. The primary endpoint was cardiac death.nnnRESULTSnPredictors of ASCD manifestation included age (odd ratio [OR]: 0.980 by 1 year increase; 95% confidence interval [CI]: 0.96 to 1.00; pxa0= 0.013), hypertension (OR: 0.51; 95% CI: 0.37 to 0.70; pxa0< 0.001), hyperlipidemia (OR:xa00.38; 95% CI: 0.25 to 0.58; pxa0< 0.001), family history of sudden cardiac death (OR: 3.67; 95% CI: 1.27 to 10.6; pxa0=xa00.016), multivessel spasm (OR: 2.06; 95% CI: 1.33 to 3.19; pxa0= 0.001), and left anterior descending artery spasm (OR:xa01.40; 95% CI: 1.02 to 1.92; pxa0= 0.04). Over a median follow-up of 7.5 years, the incidence of cardiac death was significantly higher in ASCD patients (24.1 per 1,000 patient-years vs. 2.7 per 1,000 patient-years; adjusted hazard ratio [HR]: 7.26; 95% CI: 4.21 to 12.5; pxa0< 0.001). Death from any cause also occurred more frequently in ASCD patients (27.5xa0per 1,000 patient-years vs. 9.6 per 1,000 patient-years; adjusted HR: 3.00; 95% CI: 1.92 to 4.67; pxa0< 0.001). Thexa0incidence rate of recurrent ventricular tachyarrhythmia in ASCD patients was 32.4 per 1,000 patient-years, and the composite of cardiac death and ventricular tachyarrhythmia was 44.9 per 1,000 patient-years. A total of 24 ASCD patients received implantable cardioverter-defibrillators (ICDs). There was a nonsignificant trend of a lower rate of cardiac death in patients with ICDs than those without ICDs (pxa0= 0.15).nnnCONCLUSIONSnThe prognosis of patients with variant angina with ASCD was worse than other patients with variant angina. In addition, our findings supported ICDs in these high-risk patients as a secondary prevention because current multiple vasodilator therapy appeared to be less optimal.

Variation of the size of pulmonary venous ostia during the cardiac cycle: optimal reconstruction window at ECG-gated multi-detector row CT

The aim of this study was to investigate the variation of the size of pulmonary vein ostia during cardiac cycle using ECG-gated multi-detector row CT (MDCT). Nineteen patients were included in this study. Transaxial images at the level of right inferior pulmonary vein (RIPV) were reconstructed in increments of 5%. The ostial diameter of RIPV was measured, the reconstruction windows showing maximal and minimal diameters were selected. The ostial areas of four pulmonary veins were measured at axial image sets of two selected reconstruction windows. The measurement of RIPV revealed that the maximal diameter (1.50±0.32xa0cm) was generally 35% and the minimal diameter (1.28±0.28xa0cm) was usually at 85%. The measurement of ostial areas showed that the ostia enlarged at the end of ventricular systole when compared with those at the end of ventricular diastole, by the factors of 1.44±0.55 for the right superior, 1.25±0.23 for the right inferior, 1.45±0.81 for the left superior, and 1.31±0.26 for the left inferior pulmonary vein (P<0.05). The size of the pulmonary vein ostia is variable during the cardiac cycle and the measurement of the pulmonary veins should always be in the same phase of the cardiac cycle during the follow-up of patients.

Effect of Short-Term Steroid Therapy on Early Recurrence During the Blanking Period After Catheter Ablation of Atrial Fibrillation

Background—Early recurrence (ER) of atrial tachyarrhythmias during the first 3 months (blanking period) after atrial fibrillation ablation can be highly symptomatic, often requiring emergency treatment. Short-term steroid therapy may suppress ER during the blanking period. Methods and Results—We prospectively enrolled 138 patients who were randomly assigned to 2 groups (steroid group and control group). An intravenous bolus of 0.5 mg/kg of methylprednisolone for 2 days followed by 12 mg daily of oral methylprednisolone for 4 days was given to the steroid group patients. The primary end point was ER during the blanking period (3 months post ablation). During the blanking period, 51 of the 138 (37.0%) patients experienced ER after atrial fibrillation ablation. The steroid group had a lower rate of ER than the control group (15/64 [23.4%] versus 36/74 [48.6%], P=0.003). There was no difference between the 2 groups about late recurrence during a 24-month follow-up (log-rank test, P=0.918). In a multivariate analysis, short-term steroid therapy was independently associated with a lower rate of ER during the blanking period (adjusted OR, 0.45; 95% confidence interval, 0.25–0.83; P=0.01). Conclusions—Periprocedural short-term moderate intensity steroid therapy reduces ER (≈3 months) after catheter ablation of atrial fibrillation. It is not effective in preventing late (3≈24 m) atrial fibrillation recurrence. Clinical Trial Registration—URL: www.who.int/ictrp; Unique identifier: KCT0000107.

Prediction of spontaneous ventricular tachyarrhythmia by an artificial neural network using parameters gleaned from short-term heart rate variability

Highlights? Prediction of ventricular tachyarrhythmia with artificial neural network. ? Parameters of heart rate variability analysis were used as features. ? Sensitivities of the classifier were around 80%. Reducing casualties due to sudden cardiac death and predicting ventricular tachyarrhythmia (VTA), ventricular tachycardia (VT) or ventricular fibrillation (VF), is a key issue in health maintenance. In this paper, we propose a classifier that can predict VTA events using artificial neural networks (ANNs) trained with parameters from heart rate variability (HRV) analysis. The Spontaneous Ventricular Tachyarrhythmia Database (Medtronic Version 1.0), comprising 106 pre-VT records, 26 pre-VF records, and 126 control data, was used. Each data set was subjected to preprocessing and parameter extraction. After correcting the ectopic beats, data in the 5min window prior to the 10s duration of each event was cropped for parameter extraction. Extraction of the time domain and non-linear parameters was performed subsequently. Two-thirds of the database of extracted parameters was used to train the ANNs, and the remainder was used to verify the performance. Three ANNs were developed to classify each of the VT, VF, and VT+VF signals, and the sensitivities of the ANNs were 82.9% (71.4% specificity), 88.9% (92.9% specificity), and 77.3% (73.8% specificity), respectively. The normalized areas (Azs) under the receiver operating characteristic (ROC) curve of each ANNs were 0.75, 0.93, and 0.76, respectively.

Diagnosis of coronary vasospasm in patients with clinical presentation of unstable angina pectoris using ergonovine echocardiography

Although coronary vasospasm can contribute to the development of unstable angina, the definite diagnostic method has not been established. The purpose of this study was to determine if ergonovine echocardiography (detection of regional wall motion abnormality during bedside ergonovine challenge) after angiographic confirmation of insignificant fixed disease would be useful and safe in detecting coronary vasospasm in patients with unstable angina. After control of chest pain with medications in patients admitted to the coronary care unit under the tentative diagnosis of unstable angina, diagnostic coronary angiography was performed. All patients with normal or insignificant fixed disease underwent ergonovine echocardiography after discontinuation of medications for 4+/-1 days. Among 208 consecutive patients enrolled for this study, 75% (156 of 208) showed significant fixed disease in the angiography. Ergonovine echocardiography was performed in 52 patients with insignificant disease, and coronary vasospasm was documented in 33 (63%, 33 of 52). No serious procedure-related arrhythmia or myocardial infarction occurred. Esophageal motility disorder and hypertrophic cardiomyopathy were diagnosed in 6 and 3 patients, respectively. Chest pain of undetermined etiology was the final diagnosis at discharge in 10 patients (5%, 10 of 208); among them chest pain redeveloped in 2 patients, and repeated ergonovine echocardiography revealed positive results. Our data suggest that among patients with the clinical presentation of unstable angina, coronary vasospasm is the main cause of myocardial ischemia in a considerable number of patients with a normal or near-normal angiogram, and ergonovine echocardiography after confirmation of absence of significant fixed disease is useful and safe for noninvasive diagnosis of coronary vasospasm in this setting.

Second coupling interval of nonsustained ventricular tachycardia to distinguish malignant from benign outflow tract ventricular tachycardias

BACKGROUNDnIdiopathic ventricular tachycardia (VT) originating from the outflow tract (OT) usually is considered a benign condition. In rare cases, patients with OT-VT suffer from syncope or even sudden cardiac death. OT-VT is frequently preceded by nonsustained VT (NSVT).nnnOBJECTIVEnThe purpose of this study was to clarify if the ECG parameters of NSVTs could differentiate malignant from benign OT-VT.nnnMETHODSnWe retrospectively evaluated patients without structural heart disease who had documented OT-NSVT on ECG. ECG parameters were compared between patients with syncope, aborted sudden cardiac death, or ventricular fibrillation (malignant group, n = 36) and patients without syncope (benign group, n = 40).nnnRESULTSnThere were no differences with regard to age and gender between the malignant and benign groups. On analysis of NSVT, the first coupling interval (CI) of NSVT was comparable between the 2 groups (458 ± 87 ms vs 485 ± 95 ms, P = .212). However, the second CI of NSVT beats was significantly shorter in the malignant group (313 ± 58 ms vs 385 ± 83 ms, P < .0001). During 48-month follow-up, the benign group had a significantly lower recurrence of clinical VT than the malignant group (P = .046). The malignant group frequently had more than 1 focus of VT, whereas the benign group showed only a single focus (1.82 vs 1.09, P = .023).nnnCONCLUSIONnThe second CI of NSVT in the malignant group was significantly shorter than that of the benign OT-VT group. Careful measurement of the second CI of NSVT may help identify the malignant form of OT-VT, enabling early treatment to prevent future cardiac events.