Reduction of atrial fibrillation in remotely monitored pacemaker patients: results from a Chinese multicentre registry / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Many recipients of implantable cardiac electronic devices have atrial fibrillation (AF) occurrences after device implantation, even if there is no previous history of AF, and some of the episodes are asymptomatic. The purpose of this study was to evaluate trends in AF burden following early AF detection in patients treated with pacemakers equipped with automatic, daily Home Monitoring function.</p><p><b>METHODS</b>Between February 2009 and December 2010, the registry recruited 701 pacemaker patients (628 dual-chamber, 73 biventricular devices) at 97 clinical centers in China. Daily Home Monitoring data transmissions were analyzed to screen for the AF burden. In-office follow-ups were scheduled for 3 and 6 months after implantation. Upon first AF (i.e., mode-switch) detection in a patient, screening of AF burden by Home Monitoring was extended for the next 180 days.</p><p><b>RESULTS</b>At least one episode of AF was observed in 22.9% of patients with dual-chamber pacemakers and in 28.8% of patients with biventricular pacemakers. The first AF detection in a patient occurred, on average, about 2 months before scheduled follow-up visits. In both pacemaker groups, mean AF burden decreased significantly (P < 0.05) over 180 days following first AF detection: from 12.0% to 2.5% in dual-chamber and from 12.2% to 0.5% in biventricular pacemaker recipients. The number of patients with an AF burden >10% per month was significantly reduced over 6 months of implantation in both dual chamber (38 patients in the first month vs. 21 patients in month 6, P < 0.05) and biventricular (7 patients in the first month vs. 0 patient in months 4-6, P < 0.05) pacemaker recipients.</p><p><b>CONCLUSIONS</b>Automatic, daily Home Monitoring of patients treated with cardiac pacemakers allows early detection of AF, and there is a gradual and significant decrease in AF burden.</p>

Efficacy of catheter radiofrequency ablation for the treatment of ventricular arrhythmia storm post cardioverter-defibrillators implantation / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the acute and long-term effects of catheter radiofrequency ablation for the treatment of ventricular arrhythmia storm (VAS) post implantable cardioverter-defibrillators (ICD) implantation.</p><p><b>METHODS</b>Acute and long-term effects of catheter radiofrequency ablation for the treatment of VAS post ICD implantation were retrospectively assessed in 11 patients from September 2008 to August 2011.</p><p><b>RESULTS</b>A total of 15 ablation procedures were performed in 11 patients. Six ablation procedures were performed through epicardial approach. In 9 patients, 20 types of ventricular tachycardia (VT) (including 20% hemodynamically unstable VT) were induced during the procedures [mean cycle length (384 ± 141) ms] and polymorphic ventricular tachycardia were induced in 7 patients. The average X-ray fluoroscopy time and procedural time were (26 ± 17) min and (189 ± 60) min, respectively. Complete success, partial success, and failure rates immediately post catheter radiofrequency ablation were 46.7% (7/15), 26.7% (4/15) and 26.7% (4/15), respectively. All patients are alive at follow-up[(2.45 ± 9.6) months after the last catheter ablation] and the complete success, partial success, and failure rates during follow-up were 72.7% (8/11), 9.1% (1/11) and 18.2% (2/11), respectively.</p><p><b>CONCLUSION</b>VAS can be effectively treated by catheter radiofrequency ablation in patients post ICD implantation.</p>

A prospective study to evaluate the efficacy of an intracardiac electrogram-based atrioventricular and interventricular intervals optimization method in cardiac resynchronization therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cardiac resynchronization therapy (CRT) with biventricular pacing improves cardiac function, functional capacity and quality of life in selected patients with heart failure. The current study aimed to evaluate the efficacy of the intracardiac electrogram (IEGM)-based optimization method, QuickOpt(TM), in Chinese patients treated with CRT.</p><p><b>METHODS</b>Aortic time velocity integrals (AVTI) achieved at the sensed atrioventricular (AV), paced AV and interventricular (VV) interval settings recommended by both QuickOpt(TM) and standard echocardiographic optimization were measured in 101 patients. Consistency and the strength of the relationship between the two timing cycle optimization methods were assessed by intra-class correlation coefficient (ICC).</p><p><b>RESULTS</b>The ICC showed good agreement and correlation with what the AVTI achieved at the optimal sensed AV (ICC = 0.9683 (0.9535 - 0.9785)), paced AV (ICC = 0.9642 (0.9475 - 0.9757)) and VV (ICC = 0.9730 (0.9602 - 0.9817)) interval settings determined by the two optimization methods. The average time required by echocardiographic optimization and by QuickOpt(TM) were (78.32 ± 32.40) minutes and (1.98 ± 1.64) minutes respectively (P < 0.0001).</p><p><b>CONCLUSION</b>The QuickOpt(TM) algorithm provides a quicker, simpler and reliable alternative to the standard method for timing cycle optimization.</p>

Effects of metoprolol on electrophysiology of ischemic and anoxic myocardium in diabetic rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of metoprolol on electrophysiology of ischemic and anoxic myocardium in diabetic rats.</p><p><b>METHODS</b>Forty Sprague-Dawley (SD) rats were divided into 4 groups: diabetes group; diabetes and ablation of left sympathetic nerve group; diabetes and metoprolol group and sham group. The diabetes model was induced by intraperitoneal injection of streptozotocin (STZ, 60 mg/kg). The ventricular diastolic effective threshold (DET), effective refractive period (ERP), and Ventricular fibrillation threshold (VFT) were measured. The serum concentration of nerve growth factor (NGF) was measured.</p><p><b>RESULTS</b>Metoprolol increased DET of ischemic and anoxic myocardium in diabetic rats. The ablation of the left sympathetic nerve increased VFT of diabetic rats. VFT in metoprolo group was significantly increased compared to diabetes group after ischemia. The concentrations of NGF in diabetic group and metoprolol group were higher than those in sham group. There were no difference in NGF levels between ablation of left sympathetic nerve group and sham group.</p><p><b>CONCLUSION</b>The remodeling of sympathetic nerve affects the electrophysiology of ischemic myocardium of diabetic rats. Metoprolol can increase the VFT and decrease the excitation threshold of the ischemic myocardium in diabetic rats.</p>

Application of double source multidetector computed tomography in visualization of cardiac veins / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To evaluate the value of double source multidetector computed tomography (MDCT) in visualization of cardiac veins in patients with chronic heart failure.</p><p><b>METHODS</b>Thirty-five patients with chronic heart failure (aged 65.4 ± 8.8, 21 males and 14 females) were enrolled in the study. In Group A, MDCT and retrograde coronary venography (RCV) were performed consecutively; in Group B anterograde visualization of the coronary venous and RCV were performed.</p><p><b>RESULTS</b>Coronary sinus, GCV and MCV of all individuals were identified in MDCT. LVPV was observed in 65% patients of Group A, and 66.7% patients of Group B. The correlation coefficient between MDCT and RCV was 0.944, and that between CVG and RCV was 0.42.</p><p><b>CONCLUSION</b>Non-invasive evaluation of cardiac veins with double source CT is feasible and may be used in cardiac resynchronization therapy.</p>

Involvement of potassium channel in hemin-induced cardioprotection in rat hearts / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of heme oxygenase 1 inducer hemin on protection of ischemia-reperfusion injury in rats and its mechanisms.</p><p><b>METHODS</b>The Langendorff model of isolated rat heart was used; the left anterior descending coronary artery was occluded for 30 min and subsequently reperfused for 2 h. Then the ventricular function and infarct size were measured.</p><p><b>RESULT</b>Hemin preconditioning prevented the increase in LVEDP, decrease in LVDP and +/- dp/dt(max) in the isolated ischemia-reperfusion rat hearts. The leakage of LDH and CK in the coronary effluent was significantly declined in hemin-treated rat hearts. And the infarct size was also reduced. Administration of a blocker of mitochondrial ATP-sensitive potassium channel (mitoK(ATP)) 5-HD (5 mg/kg) before hemin preconditioning increased the LVEDP, and reduced the LVDP and +/- dp/dt(max). The leakage of LDH and CK in the coronary effluent and the infarct size were also increased compared with only hemin-treated rat hearts. Pretreatment of the rats with a blocker of sarcolemmal ATP-sensitive potassium channel (sarcK(ATP)) HMR-1098 (6 mg/kg) before hemin preconditioning also abolished the protective effect. Infusion of paxilline (1 micromol/L), a blocker of calcium activated potassium channel (K(Ca)) for 10 min before ischemia/reperfusion led to larger infarct size and poorer myocardial performance as compared with the hemin group. The leakage of LDH and CK in the coronary effluent was also increased.</p><p><b>CONCLUSION</b>Both mitoK(ATP)and sarcK(ATP)channels activation are required for the delayed cardioprotection induced by hemin. The opening of K(Ca) channels-dependent mechanism may be involved in the protection.</p>

COX-2 and HO-1 are involved in the delayed preconditioning elicited by bradykinin in rat hearts / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate whether cyclooxygenase-2 (COX-2) and heme oxygenase-1 (HO-1) are involved in the bradykinin-induced delayed protection.</p><p><b>METHODS</b>Cardiac contractility, lactate dehydrogenase (LDH) and infarct area were analyzed in isolated rat hearts undergoing ischemia-reperfusion injury induced by Langendorff method.</p><p><b>RESULT</b>Conscious rats received bradykinin (40 microg/kg), and the isolated hearts were subjected to 30 min of regional ischemia and 120 min of reperfusion 24 h later. Bradykinin pretreatment would improve post-ischemic performance, and reduced the release of LDH and infarct size. COX-2 inhibitor celecoxib (3 mg/kg) abolished bradykinin-induced protection, leading to poorer myocardial performance, release of more LDH and larger infarct sizes. Administration of HO-1 inhibitor ZnPP IX(20 microg/kg) before bradykinin partially abrogated the delayed protection. Pretreatment with the mitochondrial ATP sensitive potassium channel(mitoK(ATP) antagonist 5-HD before or 24 h after bradykinin administration also abolished the effect of protection.</p><p><b>CONCLUSION</b>The results indicate that activation of HO-1 and COX-2 might be involved in the delayed cardioprotection evoked by bradykinin, and mitoK(ATP) channel may serve as both a trigger and a mediator in the cardioprotection.</p>

Comparison of the antithrombotlic effect and safety between intravenous nadroparin and unfractionated heparin in patients undergoing percutaneous coronary intervention / 中华心血管病杂志

<p><b>OBJECTIVE</b>The study was designed to compare the antithrombotic property and safety between nadroparin and unfractionated heparin during percutaneous coronary intervention (PCI).</p><p><b>METHODS</b>A prospective, single blind, randomized study was performed. A total of 98 patients (aged 65.1 +/- 8.6 years, female, 28.6%, diabetes, 7.1%) undergoing selective PCI were randomized to be administered intravenously either nadroparin (0.075 ml/10 kg) or unfractionated heparin (100U/kg) for procedural anticoagulation, in whom stable angina was 42.9%, unstable angina, 27.6%, myocardial infarction, 29.6%, two or three-vessel disease, 23.5%, stent, 100%. Blood samples for anti-Xa level were assayed in the first 22 patients of the nadroparin group before and after administration at the following intervals: 8 min, 1 h, 2 h and 4 h. Bleeding complications were classified according to Thrombolysis In Myocardial Infarction (TIMI) criteria. The bleeding index (change in hemoglobin) was calculated. All patients were monitored for adverse clinical events (i.e. death, myocardial infarction, need for revascularization) during the period of 30 days after PCI.</p><p><b>RESULTS</b>(1) There were no significant differences in baseline characteristics between the two randomized groups. (2) Plasma anti-Xa activities were 0.10 +/- 0.00 IU/ml at the time just before the administration of nadroparin, 1.89 +/- 0.24 IU/ml, 0.96 +/- 0.24 IU/ml, 0.47 +/- 0.13 IU/ml, and 0.30 +/- 0.12 IU/ml at the time of 8 min, 1 h, 2 h and 4 h after the use of nadroparin (and the rate of > 0.5 IU/ml were 100%, 100%, 45% and 9% patients), respectively. (3) There were no significant differences in the mean bleeding index, post-PCI hemoglobin and hematocrit between nadroparin and unfractionated heparin group [(1.16 +/- 5.80) g/L vs (0.90 +/- 6.50) g/L, P = 0.858; (129.5 +/- 13.6) g/L vs (125.5 +/- 14.9) g/L, P = 0.175; (39.0 +/- 3.9)% vs (37.9 +/- 4.6)%, P = 0.205]. (4) None of the patients in two randomized groups were observed hemorrhagic events, which including TIMI major or minor bleeding complications, gross or microscopic hematuria, melena, positive stool occult blood. There were no blood transfusions and no hematoma at the vascular access site in either of the group. (5) No death, no recurrent angina pectoris, and no urgent revascularization occurred within 30 days in both groups. One patient in nadroparin group was observed "no reflow" phenomenon that was accompanied with an elevated ST segment and a risen serum level of cTnI. This patient was diagnosed as non-Q-wave myocardial infarction. Though no myocardial infarction was found in unfractionated heparin group, there was no significant difference in the rate of myocardial infarction between the two groups of the study (P = 0.970).</p><p><b>CONCLUSIONS</b>The administration of nadroparin before PCI seems effective and safe. Compared with unfractionated heparin, nadroparin was associated with neither an excess of bleeding nor an increase of clinical complications in this study.</p>