Fast rate (≥ 250 beats/min) right ventricular burst stimulation is useful for ventricular tachycardia induction in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: One of the major challenges in arrhythmogenic right ventricular cardiomyopathy (ARVC) ablation is ventricular tachycardia (VT) non-inducibility. The study aimed to assess whether fast rate (≥ 250 beats/min) right ventricular burst stimulation was useful for VT induction in patients with ARVC. METHODS: Ninety-one consecutive ARVC patients with clinical sustained VT that underwent electrophysiological study were enrolled. The stimulation protocol was implemented at both right ventricular apex and outflow tract as follows: Step A, up to double extra-stimuli; Step B, incremental stimulation with low rate (< 250 beats/min); Step C, burst stimulation with fast rate (≥ 250 beats/min); Step D, repeated all steps above with intravenous infusion of isoproterenol. RESULTS: A total of 76 patients had inducible VT (83.5%), among which 49 were induced by Step C, 15 were induced by Step B, 8 and 4 by Step A and D, respectively. Clinical VTs were induced in 60 patients (65.9%). Only two spontaneously ceased ventricular fibrillations were induced by Step C. Multivariate analysis showed that a narrower baseline QRS duration under sinus rhythm was independently associated with VT non-inducibility (OR: 1.1; 95% CI: 1.0-1.1; P = 0.019). CONCLUSION: Fast rate (≥ 250 beats/min) right ventricular burst stimulation provides a useful supplemental method for VT induction in ARVC patients.

Impact of body mass index on plasma N-terminal ProB-type natriuretic peptides in Chinese atrial fibrillation patients without heart failure.

BACKGROUND: An inverse relationship between body mass index (BMI) and circulating levels of N-terminal proB-type natriuretic peptide (NT-proBNP) has been demonstrated in subjects with and without heart failure. Obesity also has been linked with increased incidence of atrial fibrillation (AF), but its influence on NT-proBNP concentrations in AF patients remains unclear. This study aimed to investigate the effect of BMI on NT-proBNP levels in AF patients without heart failure. METHODS: A total of 239 consecutive patients with AF undergoing catheter ablation were evaluated. Levels of NT-proBNP and clinical characteristics were compared in overweight or obese (BMI≥25 kg/m2) and normal weight (BMI<25 kg/m2) patients. RESULTS: Of 239 patients, 129 (54%) were overweight or obese. Overweight or obese patients were younger, more likely to have a history of nonparoxysmal AF, hypertension, and diabetes mellitus. Levels of NT-proBNP were significantly lower in overweight or obese than in normal weight subjects (P<0.05). The relationship of obesity and decreased NT-proBNP levels persisted in subgroup of hypertension, both gender and both age levels (≥65 yrs and <65 yrs).Multivariate linear regression identified BMI as an independent negative correlate of LogNT-proBNP level. CONCLUSIONS: An inverse relationship between BMI and plasma NT-proBNP concentrations have been demonstrated in AF patients without heart failure. Overweight or obese patients with AF appear to have lower NT-proBNP levels than normal weight patients.

Screening of pathogenic genes in Chinese patients with arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heritable cardiac disease predominantly caused by mutations in desmosomal protein genes. Previous genetic analyses of the Chinese ARVC population are limited to small size and restriction to a single gene. This study was aimed to investigate the genotype in a large series of Chinese patients with ARVC through comprehensively screening nine ARVC-causing genes. METHODS: A total of 100 unrelated ARVC patients and 300 age, gender and ethnicity matched healthy controls were genetically tested with multiplexing targeted resequencing for nine previously reported ARVC-causing genes, including plakophilin-2, desmoplakin, desmoglein-2, desmocollin-2, plakoglobin, transforming growth factor beta-3, transmembrane protein 43, desmin and Lamin A/C. RESULTS: Fifty-nine mutations were identified in 64% of the patients, among which, 93% were located in desmosomal protein genes. Plakophilin-2 mutations accounted for 54% of the total and 58% of the desmosomal mutations, with a truncating mutation type making up about 2/3 of the plakophilin-2 mutations. Only four mutations were found in non-desmosomal genes; two in transmembrane protein 43 and two in transforming growth factor beta-3. Two of them (one of each gene) appeared as single missense mutations. No mutation was identified in desmin or Lamin A/C. Multiple mutations were found in 23% of the patients, with plakophilin-2 being found in 57% of the multi-mutation carriers. CONCLUSIONS: Plakophilin-2 was the most common gene mutation that was identified in Chinese ARVC patients. Non-desmosomal genes should be added to desmosomal protein genes when performing molecular genetic screening in patients with suspected ARVC.

Improved approach to atrial septum puncture: experience in 539 cases.

BACKGROUND: The transseptal puncture technique has been widely used in therapeutic left atrium catheterization. But this technique may lead to some life-threatening complications. It can not be used widely because it is restricted by economy and deferring the transseptal puncture procedure. The aim of this study was to introduce a simple and safe transseptal puncture procedure. METHODS: The distal of coronary sinus (CS) electrode was positioned close to the lateral margin of heart, which was about at 3 o'clock at left anterior oblique (LAO) 30° referred to whole cardiac profile. It was then used as the marker for the level of fossa ovalis at posterior-anterior projection to guide the pull of transseptal needle. The midpoint between the distal CS and the posterior margin of heart at right anterior oblique (RAO) 45° view was considered as the location of fossa ovalis. Once the puncture was succeeded, the guidewire was introduced to the left superior pulmonary vein via puncture sheath after the needle was retrieved. The end of outer sheath was introduced into left atrium with the protection of guidewire. It was applied in 539 patients (316 male, 223 female; (53 ± 16) years old) who underwent catheter ablation of atrial fibrillation or left-sided atrioventricular accessory pathway. RESULTS: This transseptal approach reached 100.0% success and was succeeded in 98.9% with the first attempt. The first attempt puncture was aborted due to greater resistance to needle advancement or smaller needle curve in six patients. However, the second attempts were all succeeded after the needle curve was reshaped. There was no tamponade and embolism occurred. CONCLUSION: The atrial septum puncture approach using the location of distal CS electrode as important marker and the guidewire for protection when sending outer sheath into left atrium is reliable and safe.