Redefining left bundle branch block from high-density electroanatomical mapping.

BACKGROUND: The existing ECG criteria for diagnosing left bundle branch block (LBBB) are insufficient to distinguish between true and false blocks accurately. METHODS: We hypothesized that the notch width of the QRS complex in the lateral leads (I, avL, V5, V6) on the LBBB-like ECG could further confirm the diagnosis of true complete left bundle branch block (t-LBBB). We conducted high-density, three-dimensional electroanatomical mapping in the cardiac chambers of 37 patients scheduled to undergo CRT. These patients' preoperative electrocardiograms met the ACC/AHA/HRS guidelines for the diagnosis of complete LBBB. If the left bundle branch potential could be mapped from the base of the heart to the apex on the left ventricular septum, it was defined as a false complete left bundle branch block (f-LBBB). Otherwise, it was categorized as a t-LBBB. We conducted a comparative analysis between the two groups, considering the clinical characteristics, real-time correspondence between the spread of ventricular electrical excitation and the QRS wave, QRS notch width of the lateral leads (I, avL, V5, V6), and the notch width/left ventricular end-diastolic diameter (Nw/LVd) ratio. We performed the ROC correlation analysis of Nw/LVd and t-LBBB to determine the sensitivity and specificity for diagnostic authenticity. RESULTS: Twenty-five patients were included in the t-LBBB group, while 12 patients were assigned to the f-LBBB group. Within the t-LBBB group, the first peak of the QRS notch correlated with the depolarization of the right ventricle and septum, the trough corresponded to the depolarization of the left ventricle across the left ventricle, and the second peak aligned with the depolarization of the left ventricular free wall. In contrast, within the f-LBBB group, the first peak coincided with the depolarization of the right ventricle and a majority of the left ventricle, the second peak occurred due to the depolarization of the latest, locally-activated myocardium in the left ventricle, and the trough was a result of delayed activation of the left ventricle that did not align with the usual peak timing. The QRS notch width (45.2 ± 12.3 ms vs. 52.5 ± 9.2 ms, P < 0.05) and the Nw/LVd ratio (0.65 ± 0.19 ms/mm vs. 0.81 ± 0.17 ms/mm, P < 0.05) were compared between the two groups. After conducting the ROC correlation analysis, a sensitivity of 56% and a specificity of 91.7% for diagnosing t-LBBB using Nw/LVd were obtained. CONCLUSION: By utilizing the current diagnostic criteria for LBBB, an increased Nw/LVd value can enhance the effectiveness of diagnosing LBBB.

Performance of Subcutaneous Implantable Cardioverter Defibrillator (S-ICD) in Chinese Population with Primary Prevention Indications: A Prospective Observational Cohort Study.

BACKGROUND International studies have shown that use of a subcutaneous implantable cardioverter defibrillator (S-ICD) could reduce lead-related complications while maintaining adequate defibrillation performance; however, data from the Chinese population or other Asian groups are limited. MATERIAL AND METHODS SCOPE is a prospective, multicenter, observational cohort study. Two hundred patients with primary prevention indication for sudden cardiac death (SCD), who are candidates for S-ICD, will be enrolled. From the same population, another 200 patients who are candidates for transvenous implantable cardioverter defibrillator (TV-ICD) will be enrolled after being matched for age, sex, SCD high-risk etiology (ischemic cardiomyopathy, and non-ischemic cardiomyopathy, ion channel disease, and other) and atrial fibrillation in a 1: 1 ratio with enrolled S-ICD patients. All the patients will be followed for 18 months under standard of care. RESULTS The primary endpoint is proportion of patients free from inappropriate shock (IAS) at 18 months in the S-ICD group. The lower 95% confidence bound of the proportion will be compared with a performance goal of 90.3%, which was derived from the previous meta-analysis. The comparisons between S-ICD and TV-ICD on IAS, appropriate shock, and complications will be used as secondary endpoints without formal assumptions. CONCLUSIONS This is the first prospective multicenter study focusing on the long-term performance of S-ICD in a Chinese population. By comparing with the data derived from international historical studies and a matched TV-ICD group, data from SCOPE will allow for the assessment of S-ICD in the Chinese population in a contemporary real-world implantation level and programming techniques, which will help us to further modify the device implantation and programming protocol in this specific population in the future.

Feasibility study on cardiac resynchronization in the treatment of heart failure by single left bundle branch pacing.

To examine the feasibility of single left bundle branch pacing for cardiac resynchronization therapy (CRT) by carrying out a frequency adaptive atrioventricular delay (RAAVD) algorithm and automatic optimization of the single left bundle branch pacing atrioventricular interval (AVI) based on the right atrioventricular interval (RAS-RVS). Thirty-six patients with CRT class Ia indications according to the European Society of Cardiology 2016 guidelines and implanted with RAAVD functional three-chamber pacemakers were prospectively enrolled in this study. Patients were divided into a single left bundle branch pacing group (n = 21) and a standard biventricular pacing group (n = 15). The optimization of the two groups was performed under standard cardiac colour Doppler ultrasound, followed by the comparison of the QRS width, cardiac function improvement, and echocardiography indicators. The ratio of AVI to the right atrial-right ventricular interval (RAS-RVS) after single LV pacing optimization was defined as the single left bundle branch pacing coefficient (LUBBPε). In comparison to the BVP, the QRS was significantly narrowed (P = 0.017), accompanied by a significantly increased proportion of patients with NYHA class I and II, as well as the 6MWT. Compared with standard biventricular pacing, LVEDD was significantly shortened (P = 0.045), accompanied by significantly improved LAD, AVVTI, EA distance/RR, IVMD, and TS-SD after the operation. RAS-RVS was 156 ± 33 ms, the optimized AVI was 102 ± 10 ms, and LUBBPε was calculated to be 0.66 ± 0.06. Depending on the LUBBPε, a three-chamber pacemaker with a single left bundle branch pacing system was developed based on RAS-RVS-optimized AVI automatically. A three-chamber pacemaker with single left bundle branch pacing can achieve CRT based on RAS-RVS, reaching the optimal AVI of 66% of RAS-RVS.

Three-dimensional electroanatomical mapping guidelines for the selection of pacing site to achieve cardiac resynchronization therapy.

Objectives: We aimed to evaluate the feasibility of left ventricular electroanatomical mapping to choose between left bundle branch area pacing (LBBAP) or coronary venous pacing (CVP). Background: There are several ways to achieve left ventricular activation in cardiac resynchronization therapy (CRT): LBBAP and CVP are two possible methods of delivering CRT. However, the criteria for choosing the best approach remains unknown. Methods: A total of 71 patients with heart failure, reduced ejection fraction, and left bundle branch block (LBBB) were recruited, of which 38 patients underwent the three-dimensional electroanatomical mapping of the left ventricle to accurately assess whether the left bundle branch was blocked and the block level, while the remaining 33 patients were not mapped. Patients with true LBBB achieved CRT by LBBAP, while patients with pseudo-LBBB achieved CRT by CVP. After a mean follow-up of 6 months and 1 year, the QRS duration and transthoracic echocardiography, including mechanical synchrony indices, were evaluated. Results: Twenty-five patients with true LBBB received LBBAP, while 13 without true LBBB received CVP. Seventeen patients received LBBAP, and 16 patients received CVP without mapping. Paced QRS duration after the implantation of LBBAP and CVP was significantly narrower in the mapping subgroup compared to the non-mapping subgroup. A significant increase in post-implantation left ventricular ejection fraction was observed in patients with LBBAP or CVP, and the mapping subgroup were better than the non-mapping subgroup. After a 12-month follow-up, atrioventricular, intraventricular, and biventricular synchronization were significantly improved in the mapping subgroup compared to non-mapping groups in both LBBAP and CVP. Conclusion: In our study, three-dimensional electroanatomical mapping was used to choose LBBAP or CVP for heart failure patients, which proved feasible, with better cardiac resynchronization in the long-term follow-up. Therefore, three-dimensional electroanatomical mapping before CRT appears to be a reliable method for heart failure patients with LBBB who are indicated for CRT.

Novel oral edaravone attenuates diastolic dysfunction of diabetic cardiomyopathy by activating the Nrf2 signaling pathway.

Oxidative stress plays a crucial role in the pathophysiology of diastolic dysfunction associated with diabetic cardiomyopathy. Novel oral edaravone (OED) alleviates oxidative stress by scavenging free radicals and may be suitable for the treatment of chronic diseases such as diabetic cardiomyopathy. Oral administration of OED to type 2 diabetic rats (induced by high-sugar/high-fat diet and intraperitoneal injection of streptozotocin) for 4 w decreased malondialdehyde and increased superoxide dismutase. Moreover, it significantly improved ratios of early to late diastolic peak velocity, myocardium hypertrophy accompanied by decreased cross-sectional areas of cardiomyocytes, the proportion of apoptotic cells, collagen volume fractions, and deposition of collagen I/III. In H9c2 cells, OED reduced reactive oxygen species, cell surface area, and numbers of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling-positive cells induced by glucolipotoxicity. OED remarkably upregulated expression of the nuclear factor E2-related factor (Nrf2) signaling pathway both in vivo and in vitro. In addition, OED promoted Nrf2 nuclear translocation and upregulated nicotinamide adenine dinucleotide phosphate quinone oxidoreductase and heme oxygenase. Silencing of Nrf2 abolished the protective effect of OED in H9c2 cells. Our findings demonstrate that OED has the therapeutic potential to ameliorate diastolic dysfunction associated with diabetic cardiomyopathy. Its effect was mainly achieved by attenuating hyperglycemia and hyperlipidemia-induced cardiomyocyte hypertrophy, apoptosis, and fibrosis by activating the Nrf2 signaling pathway.

Application of Insertable Cardiac Monitor in Establishing a Dog Model of Atrial Fibrillation by High-Frequency Right Atrial Pacing.

BACKGROUND On the base of traditional modeling with high-frequency atrial pacing, insertable cardiac monitor is innovatively used to track the incidence of atrial fibrillation (AF), to observe the efficiency and safety of establishment in AF model. MATERIAL AND METHODS Twelve adult beagle dogs were randomly divided into a blank control group and an AF model group. The thinnest available bipolar solid electrode lead-3830 was implanted in AF group, connected to AF pacemaker to establish a high-frequency atrial pacing model by AOO pacing mode, and the occurrence of AF was tracked in real time by an insertable cardiac monitor Reveal LINQ. The areas of the left and the right atrium were measured by echocardiography. In addition, the morphology of left atrial tissues was observed using light and electron microscopes. RESULTS The insertable cardiac monitor Reveal LINQ sensitively, conveniently, accurately, efficiently, and dynamically recorded the AF load in AF group. After the successfully establishment of the AF mode, the area of the left atrium and right atrium were significantly enlarged compared with that before modeling by echocardiography. Furthermore, the area of the left atrium and right atrium in the AF group were larger than that in the control group. The morphological observation of the left atrium tissues in both groups prompted the reconstruction of the atrial structure in dogs in the AF group. CONCLUSIONS The application of insertable cardiac monitor Reveal LINQ improves the efficiency of monitoring the AF load, with high sensitivity, convenience, and accuracy.

Panax notoginsenoside saponins Rb1 regulates the expressions of Akt/ mTOR/PTEN signals in the hippocampus after focal cerebral ischemia in rats.

Panax notoginsenoside saponins Rb1 (PNS-Rb1) is an important active ingredient of panax notoginseng for effective treatment of cerebrovascular diseases. However, the mechanism underlying its actions in the state of cerebral ischemia is still unclear. We asked whether the potential neuroprotection of PNS-Rb1 on the brain is due to, at least partially, its modulation of AkT/mTOR/PTEN signalling pathway along with down-regulation of caspase-3 in rats subjected to phototrombic stroke. To test this hypothesis, rats with induced photothrombotic stroke were treated with PNS-Rb1 (applied in three different doses, 25 mg/kg, 50 mg/kg,100 mg/kg, respectively) or saline, while sham operated rats injected with saline were used as the control. Our results indicate that PNS-Rb1 significantly alleviated the morphological lesion concomitant with improvement of cognitive and sensorimotor deficits induced by ischemic stroke. Moreover, immunohistochemistry and Western blot analyses showed that PNS Rb1 in a dose dependent manner increased the expressions of P-Akt, P-mTOR and reduced P-PTEN and caspase-3. The present study suggests that the improvement of cognitive and sensorimotor deficits by PNS-Rb1 is made, at least partially, by the modulation of the Akt/mTOR/PTEN signalling pathway.

Left Univentricular Pacing by Rate-Adaptive Atrioventricular Delay in Treatment of Chronic Heart Failure.

BACKGROUND Cardiac resynchronization therapy (CRT) is efficacious in the treatment of chronic heart failure (CHF); however, because it is non-physiological, some patients are unresponsive. The present study used rate-adaptive atrioventricular delay (RAAVD) to track the physiological atrioventricular delay and investigated the effects of left univentricular pacing on CRT. MATERIAL AND METHODS Patients with CHF fulfilling the indication of CRT Class I were categorized into a left univentricular pacing by RAAVD group and a standard biventricular pacing group. Preoperative and postoperative electrocardiography QRS duration, echocardiographic indicators, quality of life, cardiac function, and annual treatment cost were estimated. The standard deviation (RS/R-SD5) of the S/R ratio in lead V1 at 5 heart rate segments in the left univentricular pacing by RAAVD was calculated, and the accuracy of RAAVD in tracking the physiological AV delay was evaluated. RESULTS The comparison between the left univentricular pacing by RAAVD group and the standard biventricular pacing group after operation showed a significantly reduced QRS duration (137±11 vs. 144±11 ms, P<0.05), increased AVVTI (21.84±2.25 vs. 20.45±2.12 cm, P<0.05), reduced IVMD (64.27±12.29 vs. 71.39±13.64 ms, P<0.05), decreased MRA (3.09±1.12 vs. 3.73±1.19 cm², P<0.05), and reduced average annual treatment cost (1.30±0.1 vs. 2.20±0.2 million Yuan, P<0.05). The RS/R-SD5 in the left univentricular pacing by RAAVD group was negatively correlated with improvements in cardiac function (r=-0.394, P=0.031). CONCLUSIONS Left univentricular pacing by RAAVD has treatment effects similar to those of standard biventricular pacing, and is an economically and physiologically effective method for biventricular systolic resynchronization in the treatment of CHF.

Left univentricular pacing for cardiac resynchronization therapy using rate-adaptive atrioventricular delay.

OBJECTIVE: To evaluate left univentricular (LUV) pacing for cardiac resynchronization therapy (CRT) using a rate-adaptive atrioventricular delay (RAAVD) algorithm to track physiological atrioventricular delay (AVD). METHODS: A total of 72 patients with congestive heart failure (CHF) were randomized to RAAVD LUV pacing versus standard biventricular (BiV) pacing in a 1: 1 ratio. Echocardiography was used to optimize AVD for both groups. The effects of sequential BiV pacing and LUV pacing with optimized A-V (right atrio-LV) delay using an RAAVD algorithm were compared. The standard deviation (SD) of the S/R ratio in lead V1 at five heart rate (HR) segments (RS/R-SD5), defined as the "tracking index," was used to evaluate the accuracy of the RAAVD algorithm for tracking physiological AVD. RESULTS: The QRS complex duration (132 ± 9.8 vs. 138 ± 10 ms, P < 0.05), the time required for optimization (21 ± 5 vs. 50 ± 8 min, P < 0.001), the mitral regurgitant area (1.9 ± 1.1 vs. 2.5 ± 1.3 cm2, P < 0.05), the interventricular mechanical delay time (60.7 ± 13.3 ms vs. 68.3 ± 14.2 ms, P < 0.05), and the average annual cost (13,200 ± 1000 vs. 21,600 ± 2000 RMB, P < 0.001) in the RAAVD LUV pacing group were significantly less than those in the standard BiV pacing group. The aortic valve velocity-time integral in the RAAVD LUV pacing group was greater than that in the standard BiV pacing group (22.7 ± 2.2 vs. 21.4 ± 2.1 cm, P < 0.05). The RS/R-SD5 was 4.08 ± 1.91 in the RAAVD LUV pacing group, and was significantly negatively correlated with improved left ventricular ejection fraction (LVEF) (ΔLVEF, Pearson's r = -0.427, P = 0.009), and positively correlated with New York Heart Association class (Spearman's r = 0.348, P = 0.037). CONCLUSIONS: RAAVD LUV pacing is as effective as standard BiV pacing, can be more physiological than standard BiV pacing, and can decrease the average annual cost of CRT.

Effects of Panax notoginseng ginsenoside Rb1 on abnormal hippocampal microenvironment in rats.

Cerebral ischemia damages central neurons, and abnormal microenvironment in ischemic condition is the key factor to the damages. The increase of local concentration of glutamic acid, the overload of Ca2+, and the mitochondrial stress caused by release of cytochrome C are important factors of abnormal microenvironment in cerebral ischemia. In this study ginsenoside Rb1, a compound from Panax Notoginseng, was used to intervene abnormal environment of neurons in the hippocampal CA1 region in two animal models (microperfusion model and photothrombosis model). RESULTS: Compared with the vehicle in the sham group, ginsenoside had following effects. a) ginsenoside Rb1 increased the regional cerebral blood flow (rCBF) and the stability of neuronal ultrastructure in in the hippocampal CA1 region and improved the adaptability of neurons in two models. b) ginsenoside Rb1 improved the expression level of glial glutamate transporter1 (GLT-1) and reversed the uptake of glutamate (Glu) after ischemia, and as a result thereby decreased the excitability of Glu and the expression level of GLT-1 was proportional to the dose of ginsenoside Rb1 and similar to that of Nimodipine. c) ginsenoside Rb1 inhibited the expression level of NMDAR and the overload of Ca2+, thereby reducing neuronal damages. Meanwhile, the expression level of NMDAR was inversely proportional to the dose of ginsenoside Rb1, which was similar to that of Nimodipine. d) ginsenoside Rb1 decreased the release of cytochrome C (Cyt-C) and reduced the damages caused by neuronal mitochondrial stress. Meanwhile, the release of Cyt-C was inversely proportional to the dose of ginsenoside Rb1, which was similar to that of Nimodipine. Ginsenoside Rb1 may be as an effective drug for neuroprotection and improve cerebral blood flow after acute ischemia and prevent the secondary brain damage induced by stroke.

Value of Implantable Loop Recorders in Monitoring Efficacy of Radiofrequency Catheter Ablation in Atrial Fibrillation.

BACKGROUND The aim of this study was to evaluate the value of the implantable loop recorder (ILR) in diagnosing atrial fibrillation (AF) and assessing the postoperative efficacy of radiofrequency catheter ablation (RFCA). MATERIAL AND METHODS A total of 32 patients who successfully underwent RFCA were selected. These patients discontinued antiarrhythmic medication with no AF recurrence for more than 3 months after RFCA, and underwent ILR placement by a conventional method. The clinical manifestations and information on arrhythmias recorded by the ILR were followed up to assess the efficacy of AF RFCA. RESULTS The mean follow-up period was 24.7±12.5 months. Of 32 patients with ILR information, 27 had successful RFCA and 5 had recurrent AF. The follow-up results obtained by traditional methods showed 29 patients with successful RFCA and 3 with recurrent AF (P<0.05). Among the 18 patients with clinical symptoms, 13 had recorded cardiac arrhythmic events (72.2%) and 5 showed sinus rhythm (27.8%). The ILRs recorded 18 patients with arrhythmic events (56.3%), including 12 cases of atrial arrhythmias, among whom 5 recurred at 9, 12, 16, 17, and 32 months after AF RFCA; there were also 2 patients with ventricular tachycardia (VT) and 4 with bradycardia. CONCLUSIONS The value of ILR in assessing the efficacy of AF RFCA was superior to that of traditional methods. ILR can promptly detect asymptomatic AF, and can monitor electrocardiogram features after RFCA, thus providing objective evidence of efficacy.

Effect of cardiac shock wave therapy on the microvolt T wave alternans of patients with coronary artery disease.

OBJECTIVE: The aim of this study was to evaluate the effect of cardiac shock wave therapy (CSWT) on microvolt T wave alternans (MTWA) in patients with coronary artery disease (CAD). METHODS: 87 patients with old myocardial infarction (OMI) were enrolled in this study. Sixty-two patients were randomized into the CSWT group, 32 patients into the regular treatment group (Group A) according to different shock wave procedure, and 30 into the expanding scope treatment group (Group B), and 25 patients were randomized into the control group (Group C). But the shock wave (SW) energy was only applied to the patients in the CSWT group and not to the patients in the control group. Three months was a treatment course, thus patients received a total of 9 CSWT treatment sessions. RESULTS: Technetium-99m sestamibi myocardial perfusion, fluorine-18 fluorodeoxyglucose myocardial metabolism single-photon emission computed tomography (SPECT) were performed to identify segments of myocardial ischemia, myocardial viability, and microvolt T wave alternans (MTWA) before and after CSWT. After CSWT, the rehospitalization rates of CSWT group were lower than control group (P<0.05). The myocardial ischemic segments, metabolism abnormal segments, total radioactive score of perfusion imaging and metabolism imaging, MTWA, and MTWA/HR in CSWT group were reduced significantly (P<0.05). And the heart rate of maximum MTWA, exercise time were increased significantly (P<0.05). All of the parameters in the control group did not change significantly even worsen after the treatment (P>0.05). CONCLUSIONS: CSWT can reduce the MTWA value, improve the heart chronotropic function and increase the threshold of frequency which causes MTWA.

Safe and efectivef guidance by intracardiac echocardiography for transcatheter closure in atrial septal defects.

BACKGROUND: The aim of this study was to investigate the clinical outcome of intracardiac echocardiography (ICE) for transcatheter closure of atrial septal defect (ASD) compared with the trans-esophageal echocardiography (TEE) guided method. METHODS: From May 2010 to April 2011, 46 patients who underwent ICE guided (n=23) or TEE guided (n=23) transcatheter closure of ASD were analyzed retrospectively. We compared the demographic characteristic, procedure parameters and outcomes between ICE- and TEE-guided groups. RESULTS: No significant difference was found between 2 groups on demographic characteristics. Fluoroscopy time and procedure time was significantly decreased in ICE guided group than that in TEE-guided group. In addition, no significant difference was found on treatment outcomes, complications between these 2 groups. CONCLUSION: ICE-guided ASD occlusion is safe and effective method, which provides more accurate anatomical information, shorter fluoroscopy time and procedure time.

Biventricular pacing with ventricular fusion by intrinsic activation in cardiac resynchronization therapy.

We sought to evaluate the impact of biventricular (BiV) pacing with ventricular fusion by intrinsic atrioventricular nodal (AVN) conduction (BiV + intrinsic pacing) on clinical outcomes in patients with chronic heart failure (CHF) receiving cardiac resynchronization therapy (CRT).A total of 44 patients were randomized to receive either BiV or BiV + intrinsic pacing for one month. Echocardiographic optimization was performed for the BiV pacing mode, while the BiV + intrinsic pacing mode was achieved by titrating AV delay under electrocardiography (ECG) monitoring. Symptoms, quality of life, ECG, echocardiography, and cardiovascular events were recorded at baseline and the end of the follow-up for each pacing mode.Patients undergoing BiV + intrinsic pacing mode had shorter QRS duration compared to those with conventional BiV pacing (118.4 ± 21.6 ms versus 146.4 ± 5.3 ms, P < 0.0001). Also, these patients had improved echocardiographic left ventricular fractional shortening (LVFS) (17.4 ± 5.9 versus 15.7 ± 4.9, P = 0.019), higher left ventricular ejection fraction (LVEF) (35.5 ± 9.7 versus 32.7 ± 9.7, P = 0.048), longer 6-minute walk test (6MWT) (372.5 ± 80.9 m versus 328.7 ± 108.9 m, P = 0.0001), and better Minnesota Living with Heart Failure Questionnaire (MLHFQ) scores (12.5 ± 6.6 versus 18.2 ± 12.3, P = 0.0001).Treating CHF patients with BiV+intrinsic pacing resulted in improved cardiac function and quality of life. BiV + intrinsic pacing can be used in CHF patients with sinus rhythm and normal AV nodal conduction to improve CRT efficacy.

Cardiac resynchronization therapy (CRT) with right ventricular sense triggered left ventricular pacing benefits for the hemodynamics compared with standard CRT for chronic congestive heart failure: A cross-over study.

BACKGROUND: The aim of this study was to investigate the effect of cardiac resynchronization therapy (CRT) with right ventricular (RV) sense triggered left ventricular (LV) pacing for chronic heart failure (CHF). METHODS: Thirty patients who were eligible for the Class I indication of CRT were enrolled and the informed consents were signed. Left ventricular ejection fraction (LVEF), diastolic mitral flow velocity time integral (VTI), mitral regurgitation flow VTI, and aortic valve flow VTI were measured with GE Vivid 7 (GE Medical, Milwaukee, WI, USA) before and after CRT. The echocardiographic measurements and the average annual costs of the device use were compared. RESULTS: The duration of QRS complex, the length of time used for optimization, and the average annual cost of the device use under RV sense triggered LV pacing were significantly less than that under standard biventricular (BiV) pacing (p < 0.01), while the average battery lifetime was longer. Subgroup analysis showed that LVEF, diastolic mitral flow VTI, and aortic valve flow VTI under RV sense triggered LV pacing were greater than that under standard BiV pacing with right or LV pre-activation. The average battery lifetime was significantly longer and the average annual cost of the device use was less. The mitral regurgitation flow VTI under RV sense triggered LV pacing was less than that under standard BiV pacing with RV pre-activation. CONCLUSIONS: RV sense triggered LV provides benefits for CHF patients over standard CRT in terms of maintaining the physiological atrio-ventricular delay of atrio-ventricular node and improving the acute hemodynamic effects.

Clinical and angiographic features associated with coronary collateralization in stable angina patients with chronic total occlusion.

OBJECTIVE: Coronary collateral circulation is an alternative source of blood supply to myocardium in the presence of advanced coronary artery disease. We sought to determine which clinical and angiographic variables are associated with collateral development in patients with stable angina and chronic total coronary occlusion. METHODS: Demographic variables, biochemical measurements, and angiographic findings were collected from 478 patients with stable angina and chronic total coronary occlusion. The presence and extent of collaterals supplying the distal aspect of a total coronary occlusion from the contra-lateral vessel were graded from 0 to 3 according to the Rentrop scoring system. RESULTS: Low (Rentrop score of 0 or 1) and high (Rentrop score of 2 or 3) coronary collateralizations were detected in 186 and 292 patients, respectively. Despite similar age, cigarette smoking, and medical treatment, patients with low collateralization were female in a higher proportion and less hypertensive, and had higher rates of type 2 diabetes and dyslipidemia than those with high collateralization (for all comparisons, P<0.05). In addition, patients with low collateralization exhibited more single-vessel disease, less right coronary artery occlusion, more impaired renal function, and higher serum levels of high-sensitivity C-reactive protein (hsCRP) compared with those with high collateralization. Multivariate analysis revealed that age of ≥65 years, female gender, diabetes, no history of hypertension, dyslipidemia, moderate to severe renal dysfunction, single-vessel disease, and elevated hsCRP levels were independently associated with low coronary collateralization. CONCLUSIONS: Coronary collateralization was reduced in almost 40% of stable angina patients with chronic total occlusion, which was related to clinical and angiographic factors. The impact of coronary collateralization on outcomes after revascularization needs further investigation.

Screening for significant atherosclerotic renal artery stenosis with a regression model in patients undergoing transradial coronary angiography/intervention.

OBJECTIVE: Early detection of atherosclerotic renal artery stenosis (ARAS) is clinically important with respect to blood pressure control, prevention of renal insufficiency, and even improving survival. We investigated whether the presence of significant ARAS (luminal diameter narrowing ≥70%) could be predicted using a logistic regression model before coronary angiography/intervention. METHODS: Initially, we developed a logistic regression model for detecting significant ARAS based upon clinical and angiographic features and biochemical measurements in a cohort of 1813 patients undergoing transfemoral coronary and renal angiography. This model was then prospectively applied to an additional 495 patients who received transradial renal angiography to ascertain its predictive accuracy for the presence of significant ARAS. RESULTS: Multivariate regression analysis revealed that older age (≥65 years), resistant hypertension, type 2 diabetes, creatinine clearance (Ccr) ≤60 ml/min, and multivessel coronary disease were independent predictors for significant ARAS. A logistic regression model for detecting ARAS by incorporating conventional risk factors and multivessel coronary disease was generated as: P/(1-P)=exp(-2.618+1.112[age≥65 years]+1.891[resistant hypertension]+0.453[type 2 diabetes]+0.587[Ccr≤60 ml/min]+2.254[multivessel coronary disease]). When this regression model was prospectively applied to the additional 495 patients undergoing transradial coronary and renal angiography, significant ARAS could be detected with a sensitivity of 81.2%, specificity of 88.9%, and positive and negative predictive accuracies of 53.8% and 96.7%, respectively. CONCLUSIONS: The logistic regression model generated in this study may be useful for screening for significant ARAS in patients undergoing transradial coronary angiography/intervention.

Neointimal hyperplasia persists at six months after sirolimus-eluting stent implantation in diabetic porcine.

BACKGROUND: Observational clinical studies have shown that patients with diabetes have less favorable results after percutaneous coronary intervention compared with the non-diabetic counterparts, but its mechanism remains unclear. The aim of this study was to examine the changes of neointimal hyperplasia after sirolimus-eluting stent (SES) implantation in a diabetic porcine model, and to evaluate the impact of aortic inflammation on this proliferative process. METHODS: Diabetic porcine model was created with an intravenous administration of a single dose of streptozotocin in 15 Chinese Guizhou minipigs (diabetic group); each of them received 2 SES (Firebird, Microport Co, China) implanted into 2 separated major epicardial coronary arteries. Fifteen non-diabetic minipigs with SES implantation served as controls (control group). At 6 months, the degree of neointimal hyperplasia was determined by repeat coronary angiography, intravascular ultrasound (IVUS) and histological examination. Tumor necrosis factor (TNF)-alpha protein level in the aortic intima was evaluated by Western blotting, and TNF-alpha, interleukin (IL)-1beta and IL-6 mRNA levels were assayed by reverse transcription and polymerase chain reaction. RESULTS: The distribution of stented vessels, diameter of reference vessels, and post-procedural minimal lumen diameter were comparable between the two groups. At 6-month follow-up, the degree of in-stent restenosis (40.4 +/- 24.0% vs. 20.2 +/- 17.7%, p < 0.05), late lumen loss (0.33 +/- 0.19 mm vs. 0.10 +/- 0.09 mm, p < 0.001) by quantitative angiography, percentage of intimal hyperplasia in the stented area (26.7 +/- 19.2% vs. 7.3 +/- 6.1%, p < 0.001) by IVUS, and neointimal area (1.59 +/- 0.76 mm2 vs. 0.41 +/- 0.18 mm2, p < 0.05) by histological examination were significantly exacerbated in the diabetic group than those in the controls. Significant increases in TNF-alpha protein and TNF-alpha, IL-1beta and IL-6 mRNA levels were observed in aortic intima in the diabetic group. CONCLUSION: Neointimal hyperplasia persisted at least up to 6 months after SES implantation in diabetic porcine, which may be partly related to an exaggerated inflammatory response within the blood vessel wall. Our results provide theoretical support for potential direct beneficial effects of anti-diabetic and anti-inflammation medications in reducing the risk of restenosis after stenting.

Elevation of tumor necrosis factor-alpha, interleukin-1beta and interleukin-6 levels in aortic intima of Chinese Guizhou minipigs with streptozotocin-induced diabetes.

BACKGROUND: Large animal models with toxin-mediated pancreatic damage have been used extensively in researches with respect to diabetes mellitus and cardiovascular diabetic complications. The present study aimed to establish Chinese Guizhou minipig models with streptozotocin (STZ)-induced diabetes and characterize the animal models by analyzing inflammatory cytokine levels in aortic wall, such as tumor necrosis factor (TNF)-alpha, interleukin-1beta (IL-1beta) and interleukin-6 (IL-6). METHODS: Twenty-two male Chinese Guizhou minipigs (age, 4 to 6 months; weight, 20 kg to 30 kg) were divided into STZ-induced diabetic group (n = 12) and control group (n = 10). STZ (125 mg/kg) was administrated to induce hyperglycemia and afterwards insulin was used to control fasting blood glucose levels below 10 mmol/L. Oral glucose tolerance test (OGTT) was performed before and one month after STZ administration and serum concentrations of alanine transaminase, asparagine transaminase, albumin, blood urea nitrogen, creatinine, lipids and white blood cell count were measured before and six months later. Animals in both groups were euthanized after six months and pancreas was examined immunohistochemically for islet beta cells. Aortic intima of diabetic minipigs and controls was analyzed for TNF-alpha level in tissue conditioned medium by Western blot. TNF-alpha, IL-1beta and IL-6 mRNA levels in aortic intima were assayed by reverse transcription and polymerase chain reaction (RT-PCR). RESULTS: Significant elevation in serum glucose levels was observed one month and six months after STZ induction (P < 0.001) and markedly increased OGTT values were noted, compared with baseline data. The normal pancreas had many irregular sized islets and small clusters of islet beta cells, while in pancreas of diabetic minipigs islet beta cells almost disappeared. No statistical difference was notified in serum concentrations of biochemical examinations before and six months after STZ induction. Western blot demonstrated dramatically increased TNF-alpha level in aotic intima conditioned medium, and significant elevation of TNF-alpha, IL-1beta and IL-6 mRNA levels was revealed by RT-PCR. CONCLUSIONS: The present study has established Chinese Guizhou minipig models with STZ-induced diabetes. Inflammatory cytokines (TNF-alpha, IL-1beta and IL-6) significantly elevated in aortic intima of diabetic minipigs.