Several investigators have shown that the incidence of venous obstruction after pacemaker implantation was observed in 31-50% of pacemaker patients. However, these previous reports did not investigate the venous system prior to implantation. The aim of this study was to determine the incidence and risk factors for venous obstruction in patients with transvenous pacing leads. The study included 131 consecutive patients (64 men, 67 women; mean age 71.3 +/- 9.8 years) who were investigated using intravenous digital subtraction angiography (DSA) before and after permanent pacemaker implantation. Follow-up DSA was performed for a mean interval of 44 +/- 6 months after pacemaker lead implantation in 79 of 131 patients. A diameter narrowing > 60% was defined as an obstruction. Prior to implantation of pacing leads, venous obstruction was present in 18 (13.7%) of 131 patients. In 15 of these 18 patients, the obstruction was present at the site of the left innominate vein. Follow-up DSA, after implantation of pacing leads, showed that venous obstruction was observed in 26 (32.9%) of 79 patients. There were no significant differences between obstruction and nonobstruction groups in terms of age, sex, cardiothoracic ratio, left atrial dimension, left ventricular ejection fraction, baseline heart diseases for indication of pacemaker implantation, or number and body size of pacing leads. Neither clinical symptoms nor abnormal physical findings were observed in any patients. In conclusion, the incidence of venous obstruction after pacing lead implantation is less than that of previous reports, which might be related to the incidence of venous obstruction before pacing leads implantation.

We propose that SQTS patients may exhibit different clinical manifestations depending upon their genotype.

In patients with ARVC, (1) the IDCs during sinus rhythm are related to the clinical VT and can be a target for the ablation, (2) a change in the IDC can be used as an endpoint, and (3) qualitative analyses of the serial signal-averaged ECGs may be useful for the long-term follow-up.

The truncation mutations were associated with manifestation of cardiac phenotypes in -related cardiomyopathy, suggesting that genetic analysis might be useful for diagnosis and risk stratification.

Background— Sick sinus syndrome (SSS) is a common arrhythmia often associated with aging or organic heart diseases but may also occur in a familial form with a variable mode of inheritance. Despite the identification of causative genes, including cardiac Na channel ( SCN5A ), the pathogenesis and molecular epidemiology of familial SSS remain undetermined primarily because of its rarity. Methods and Results— We genetically screened 48 members of 15 SSS families for mutations in several candidate genes and determined the functional properties of mutant Na channels using whole-cell patch clamping. We identified 6 SCN5A mutations including a compound heterozygous mutation. Heterologously expressed mutant Na channels showed loss-of-function properties of reduced or no Na current density in conjunction with gating modulations. Among 19 family members with SCN5A mutations, QT prolongation and Brugada syndrome were associated in 4 and 2 individuals, respectively. Age of onset in probands carrying SCN5A mutations was significantly less (mean±SE, 12.4±4.6 years; n=5) than in SCN5A -negative probands (47.0±4.6 years; n=10; P <0.001) or nonfamilial SSS (74.3±0.4 years; n=538; P <0.001). Meta-analysis of SSS probands carrying SCN5A mutations (n=29) indicated profound male predominance (79.3%) resembling Brugada syndrome but with a considerably earlier age of onset (20.9±3.4 years). Conclusions— The notable pathophysiological overlap between familial SSS and Na channelopathy indicates that familial SSS with SCN5A mutations may represent a subset of cardiac Na channelopathy with strong male predominance and early clinical manifestations.

No abstract

CRT may improve the prognosis and quality-of-life in patients with an IVNC with mechanical dyssynchrony.

Background: Although atrial high rate episodes (AHRE) have been commonly used to detect atrial tachyarrhythmias (AT/AF) in pacemaker patients, its reliability and characteristics are unclear. Methods and Results:39 patients with implanted dual chamber pacemakers (mean age 79.7±6.6 years), who had no history of AT/AF and were programmed in the setting of AHRE at >190 beats/min in DDD mode, were studied. An atrial overdrive pacing (AOP) algorithm was randomly programmed "ON" in 19 and "OFF" in 20 patients. AHRE were detected in 20 patients (51%), consisting of AT/AF in 15 and repetitive non-reentrant ventriculoatrial synchrony (RNRVAS) in 8 patients, all included in the AOP "ON" group. A total of 257 of 1,528 episodes of AHRE were available for analysis, including 181 and 76 episodes in the AOP "ON" and "OFF" groups, respectively. Among 181 episodes in the AOP "ON" group, 72 (40%) were RNRVAS, whereas all episodes in the AOP "OFF" group (100%) were AT/AF. Detection of RNRVAS was closely associated with a high cumulative % atrial pacing. The specificity of AT/AF detection by AHRE was 40% when the AOP algorithm was activated, vs. 100% when not in use.Conclusions: AT/AF was common in pacemaker patients without a history of AT/AF. The increase in cumulative % atrial pacing and the use of an AOP algorithm might be closely associated with RNRVAS, non-AT/AF, detected by AHRE. (Circ J 2011; 75: 1090 - 1097