Idiopathic ventricular fibrillation with fragmented QRS complex and J wave in resting electrocardiogram.

OBJECTIVE: To describe the clinical characteristics of idiopathic ventricular fibrillation (IVF) with fragmented QRS complex (f-QRS) and J wave in resting electrocardiogram. METHODS: We reviewed data from 21 case subjects in our hospital who were resuscitated after cardiac arrest due to IVF and assessed the prevalence of f-QRS and J wave in resting electrocardiogram (ECG). All the case subjects were classified among three groups based on the electrocardiographic morphology: group I, both f-QRS and J wave were observed (n = 6), group II, only J wave was observed (n = 9), group III, neither f-QRS nor J wave was observed (n = 6). Population characteristics, history of syncope or sudden cardiac arrest, incidence of ventricular fibrillation (VF), and circumstance of VF were evaluated among the three groups. RESULTS: The incidence of index events (syncope, survived cardiac arrest and VF episodes recorded in implantable cardioverter defibrillator (ICD) or pacemakers) was 13.4 ± 5.6 per-year in group I, 10.8 ± 3.9 per-year in group II, and 9.8 ± 4.2 per-year in group III. There were significant differences in incidences among the three groups, the most frequent index events were observed in group I. The hazard ratio for incidence was 3.2 (95%CI, 1.1-7.9; P = 0.01). The history and circumstance of the index events were different among the groups. In group I, all the index events occurred during sleep in early morning. In group II, four subjects suffered VF during strenuous physical activities or agitation state, two during sleep in early morning, three in usual activity. In group III, one subject suffered VF during sleep in early morning, one in agitation state, four in usual activity. CONCLUSIONS: This study suggests that the IVF patients with the combined appearance of f-QRS and J wave in the resting ECG suffer an increased risk of VF, this subgroup of IVF patients has a unique clinical feature.

Identification of the slow conduction zone in a macroreentry circuit of verapamil-sensitive idiopathic left ventricular tachycardia using electroanatomic mapping.

BACKGROUND: Although idiopathic left ventricular tachycardia (ILVT) has been shown to possess a slow conduction zone (SCZ), the details of the electrophysiological and anatomic aspects are still not well understood. OBJECTIVE: We hypothesized that the SCZ can be identified using a 3-dimensional electroanatomic (EA) mapping system. METHODS: Ten patients with ILVT were mapped using a 3-dimensional electroanatomic (EA) mapping system. After a 3-dimensional endocardial geometry of the left ventricular was created, the conduction system with left Purkinje potential (PP) and the SCZ with diastolic potential (DP) in LV were mapped during sinus rhythm (SR) and ventricular tachycardia (VT) and were tagged as special landmarks in the geometry. The electrophysiological and anatomic aspects of it were investigated. RESULTS: EA mapping during SR and VT was successfully performed in 7 patients, during VT in 3 patients. The SCZ with DPs located at the inferoposterior septum was found in 7 patients during SR and all patients during VT. The length of the SCZ was 25.2 ± 2.3 mm with conduction velocity 0.08 ± 0.01 m/s. No differences in these parameters were found between patients during SR and VT (P > 0.05). An area with PP was found within the posterior septum. A crossover junction area with DP and PP was found in 7 patients during SR and VT. This area with DP and PP during SR coincided or were in proximity to such area during VT and radiofrequency ablation targeting the site within the area abolished VT in all patients. CONCLUSION: The ILVT substrate within the junction area of the SCZ and the posterior fascicular can be identified and can be used to guide the ablation of ILVT.

[Association between abnormal electrocardiographic features and disease severity in patients with arrhythmogenic right ventricular cardiomyopathy].

OBJECTIVE: To analyze the relationship between electrocardiographic (ECG) features and disease severity in patients with the arrhythmogenic right ventricular cardiomyopathy (ARVC). METHOD: The study group consisted of 61 subjects with a definite diagnosis of ARVC on the basis of published guideline criteria and patients were divided into 3 subgroups according to the extent of diseased myocardium defined by cardiac magnetic resonance imaging (MRI): Group A: local involvement (n = 19, 31%), Group B: diffuse involvement of whole right ventricle (n = 28, 46%) and Group C: involvement of both right and left ventricles (n = 14, 23%). RESULTS: Normal electrocardiogram was shown in 1 patient in each group. Epsilon wave was detected in 24 (39%) patients, QRS duration was prolonged [≥ 110 ms (V(1)-V(3))] in 21 (34%) patients, S-wave upstroke was prolonged (≥ 55 ms) in 17 (28%) patients, complete right branch bundle block was evidenced in 10 (16%) patients and pathologic Q waves was found in 9 (15%) patients. The incidence of above abnormal ECG changes was increased in proportion to the degree of disease severity (group A < group B < group C). Incidence of Epsilon wave and prolonged QRS duration [ ≥ 110 ms (V(1)-V(3))] were significantly higher in Group C than in Group A. Incidence of prolonged S-wave upstroke (≥ 55 ms) was significantly higher in Group C than in Group A and Group B. T-wave inversion in V(1) leads was often found in Group A. T-wave inversion in inferior leads (V(1)-V(3) leads or beyond V(3)) was often presented in Group B and Group C. CONCLUSIONS: Normal ECG does not exclude the possibility of diagnosis of ARVC. The extent of T-wave inversion in the precordial leads and incidence of Epsilon wave, prolonged QRS duration [ ≥ 110 ms (V(1)-V(3))] and prolonged S-wave upstroke (≥ 55 ms) were related to degree of disease severity in patients with ARVC.

[Association between electrocardiogram characteristics and long-term outcome in patients with idiopathic ventricular fibrillation].

OBJECTIVE: To explore the association between clinical and ECG characteristics and prognoses in patients with idiopathic ventricular fibrillation (VF). METHODS: We reviewed the data from 21 VF patients [male 47.6%, mean age (38.5 ± 19.0) years] with first event of VF, all patients were resuscitated after cardiac arrest and diagnosed as idiopathic VF. The prevalence of J wave was assessed and patients were divided into J wave positive (J+ group) and negative group (J- group). The end point was death or syncope from arrhythmia, and recorded VF recurrence during the follow-up. RESULTS: J wave was frequent in subjects with idiopathic VF (71.4%). Among patients in the J+ group (15 cases), notch on the QRS wave was found in 7 subjects (46.7%), these patients were more likely to suffer from the sudden cardiac arrest during sleep at early morning than those with J wave but without notch on the QRS wave. Two patients dead suddenly in the J+ group and 1 dead from embolism in the J- group during follow-up [mean (42.4 ± 39.9) months]. The mean year-onset of VF or syncope was significantly higher in the J+ group than in the J-group [(1.3 ± 0.5) episodes/year vs. (0.4 ± 0.3) episodes/year, P < 0.01]. J wave positive was also associated with an increased risk of VF recurrence (RR 1.9, 95%CI 1.1 to 2.9, P = 0.03). CONCLUSION: J wave prevalence is high in patients with history of idiopathic VF, and positive J wave is associated with high risk of recurrence of sudden cardiac death.