Comparison of single and double vein approaches for His bundle ablation and pacemaker placement for symptomatic rapid atrial fibrillation.

BACKGROUND: His Bundle ablation (HBA) with permanent pacemaker (PPM) implantation is an effective strategy for controlling heart rate in symptomatic patients with rapid atrial fibrillation (AF), resistant to pharmacologic therapy. The standard double vein (DV) approach involves mapping and HBA from a femoral approach to achieve complete heart block (CHB), while single chamber (SC), dual chamber (DC), or biventricular (BiV) PPM is then placed via a subclavian approach. METHODS: We compared 7 patients with drug-resistant rapid AF who underwent the standard DV approach to 8 patients who underwent a single vein (SV) approach, in which HBA and PPM implantation were performed through the subclavian vein. The two groups were compared for acute success in creating CHB, total procedure and fluoroscopy times and patient discomfort. Results are expressed as mean +/- standard error (SEM). RESULTS: The procedure times for the SV versus DV were 70.4 +/- 11.4 v 100.0 +/- 19.2 min, and the fluoroscopy times, 13.9 +/- 3.1 (SV) v 13.0 +/- 2.9 (DV). All patients were discharged in stable condition with CHB and SC, DC pacemaker or BiV/Implantable Cardioverter Defibrillator (ICD). CHB with symptomatic improvement was maintained in all patients over a mean follow-up period of 22.6 months (SV), and 9.6 months (DV). CONCLUSION: The SV approach for HBA combined with PPM implantation was at least as effective and may be more efficient than the classic DV approach, and should be considered as an alternative to DV technique to reduce procedural time and patient discomfort.

Exercise-related spontaneous coronary artery dissection: case report and literature review.

BACKGROUND: Spontaneous coronary artery dissection is a rare cause of acute cardiac events and occurs most frequently in the peripartum period. Coronary artery dissection related to exercise is even more unusual, with only a few cases reported in the literature. We report a case of acute coronary artery dissection related to exercise in a 17-yr-old high school athlete, and we review the available literature on exercise-related coronary dissection. METHODS: We performed a PubMed literature search using the search terms exercise, sports, spontaneous coronary dissection, and athletics. We found seven cases of spontaneous coronary artery dissection that had occurred during intense physical exercise. Vigorous exercise can provoke acute ischemic events, but such events occur primarily in adults with atherosclerotic disease. Many of the cases reported as spontaneous coronary artery dissection are more likely atherosclerotic plaque rupture, in which cases they are not truly spontaneous. Because spontaneous coronary dissection is so rare, there are no available recommendations on how to manage young athletes with this condition. We permitted this athlete to return to limited competition, without data to support either a total restriction or even a limited restriction, with the written understanding that a recurrent event is possible but probably unlikely. In summary, spontaneous coronary artery dissection should be considered in young individuals presenting with exercise-related acute ischemic cardiac events.

VIPase autoantibodies in Fas-defective mice and patients with autoimmune disease.

The immunoregulatory neuropeptide vasoactive intestinal peptide (VIP) was cleaved by purified IgG from Fas-defective C3H/gld mice, lupus patients, and autoimmune thyroiditis patients. No VIPase activity was detected in IgG from control mice and humans. Kinetic analyses of VIPase IgG preparations suggested low-affinity recognition of VIP. Yet the VIPase activity was VIP selective, judged by lack of correlation with other protease activities expressed by the IgG and by noninterference of unrelated peptides in the activity. Recombinant Fv constructs selected from a human lupus phage show library displayed VIPase activity, confirming that the active site is located in the V domains. Inhibition of the VIPase activity by di-isopropylfluorophosphate suggested a serine protease-like mechanism of catalysis. Irreversible binding of a biotinyated phosphonate diester by the IgG and Fv preparations was observed, consistent with the presence of activated nucleophiles similar to those in enzymes capable of covalent catalysis. These observations show that VIP is a target for specific catalytic autoantibodies in autoimmune disease.