Slow Arrhythmia-related Basic And Clinical Research

Part I Evaluation of Clinical Characteristic of Sick Sinus Syndrome and Design of Genetic Association Study[Aims] To evaluate the characteristic of sick sinus syndrome and design candidate gene association study.[Methods] During January 2004 to July 2009 all sick sinus syndrome without apparent cardiac structure abnormality undertaking pacemaker implantation were included in the study. The characteristic were evaluated and controls collected. We used haploview4.2 and SNP browser for the design of candidate gene association study. The probe and primers for TaqMan method genotyping were designed too.[Results] There were 660 sick sinus syndrome patients with 264 male included in the study, the mean age was 63.84±11.40 y. A total of 185 patients had atria fibrillation. The prevalence of diabetes mellitus was higher in patients with atria fibrillation. In primary SSS, patients with atria fibrillation had a higher level of diastolic blood pressure (p<0.05) and concentration of high sensitivity C response protein.SCN5A was located in chromosome 3 and a reverse strand with a total of 7 blocks. Among them rs6599224 could capture largest number of SNP and should be selected as a candidate SNP for association study. GJA5, HCN2 and HCN4 were related to sick sinus syndrome and could be selected as candidate gene.[Conclusions]Diabetes mellitus was associated with sick sinus syndrome and atrial fibrillation; high sensitivity C response protein and diastolic blood pressure were related to atria fibrillation in primary sick sinus syndrome. The software haploview and SNP browser could help us in the design of genetic association study.Part II (1) Anticoagulation Study on Patients with Prosthetic Heart Valve (s) Undertaking Pacemaker Implantation[Aims]This study was to evaluate perioperative anticoagulation therapy in patients with mechanic heart valve(s) undergoing pacemaker implantation, seeking for a reasonable approach of perioperative anticoagulation.[Methods] A total of 109 patients with mechanical heart valve(s) undertaking pacemaker implantation were studied during January 2002 to December 2008. Fifty one patients with warfarin suspended 3 days before surgery were classified into Group 1 and 58 patients with warfarin suspended < 3 days or not at all into Group 2. The perioperative incidence of complications was compared. We also analyzed the influence of low molecular weight heparin used post surgery on the incidence of pocket heamatoma.[Results]Suspension of warfarin<3 days before surgery was associated with a higher incidence of excessive hemorrhage (16/51 vs 5/58, p=0.003). Patients with pocket heamatoma were more likely to have been treated with post-operation low molecular weight heparin (60%vs 17.3%, p=0.032). In 42 patients treated with proposed protocol of perioperative anticoagulation, no pocket heamatoma or embolism occurred.[Conclusions] A minimum of 3 days cessation of warfarin prior to surgery is preferred. Low molecular weight heparin should not be used for at least 3 days post surgery. We propose that the protocol of perioperative anticoagulation be a suspension of warfarin no less than 3 days with low molecular weight heparin bridging stopped 12 h before surgery, and warfarin rather than low molecular weight heparin initiated immediately after surgery.Part II (2) A meta Analysis of Perioperative Prescriptions of Antiplatelet and Anticoagulation in Patients Undertaking Antiarrhythmic Device Implantation[Aims] To evaluate the influence of perioperative antiplatelet and anticoagulation therapy in patients undertaking antiarrhythmic device implantation on the incidence of complications.[Methods] A meta analysis was conducted to analyze data from a total of 11 studies focusing on perioperative complications in patients undertaking antiarrhythmic device implantation. Patients were classified into six groups according to the detail of perioperative anticoagulation or antiplatelet therapy. The influence of perioperative antiplatelet and anticoagulation therapy on the incidence of surgery related complications was evaluated.[Results] From Januay 2000 to March 2010, there were 11 studies fulfilled the inclusion criterion of meta analysis. The incidence rate of hemorrhage was different among groups. The group of bridging with heparin and combined use of aspirin and clopidogrel had-a-higher incidence of hemorrhage compared to other groups(12.88%and 21.05%vs 3.44%.3.38%, 3.02%and 3.02%, p<0.001). The incidence of thromboembolism is higher in patients with oral anticoagulation withheld without bridging of heparin than that in oral anticoagulation continuation group(1.73%vs 0%, p=0.015).[Conclusions] (1) Perioperative use of aspirin(no more than 300mg daily)or warfarin alone does not increase the incidence of hemorrhage complications; (2) Dual antiplatelet therapy with aspirin and clopidogrel significantly increases the incidence of pocket heamatoma; (3) The full dose of heparin postoperatively impose patients on a higher risk of pocket heamatoma.