Sex Differences in the Relationship between Abdominal Obesity and Cardiovascular Death in Elderly Patients with Permanent Pacemakers Implantation: A Retrospective Cohort Study.

Objectives: This study aims to investigate the association between waist circumference (WC) and cardiovascular death in patients with permanent pacemakers (PPMs). Methods: This is a retrospective cohort study that enrolled patients who underwent PPM implantation in Fuwai Hospital from May 2010 to April 2014, according to the BIOTRONIK Home Monitoring database. The WC was treated as sex-specific quartiles, and patients were divided into three groups according to body mass index (BMI): normal (≤22.9 kg/m2), overweight (23-24.9 kg/m2), and obese (≥25 kg/m2). Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals for cardiovascular death according to WC and BMI in patients. Results: 492 patients with PPMs implantation were analyzed (mean age: 71.9 ± 10.8 years; 55.1% men (n = 271)). Data showed that after a mean follow-up 67.2 ± 17.5 months, 24 (4.9%) patients had experienced cardiovascular death and 71 (14.4%) were cases of all-cause mortality. Men in the third quartile of WC had an HR of 10.67 (Model 4, 95% CI: 1.00-115.21, p trend = 0.04) for cardiovascular death. However, the association disappeared in female patients (Model 4, HR = 3.99, 95% CI: 0.37-42.87, p trend = 0.25). There was no association between BMI and cardiovascular death or all-cause mortality in both male and female patients. Conclusions: Abdominal obesity was associated with an increased risk of cardiovascular death in patients with PPMs, and this relationship was only in male patients.

Association of time-varying changes in physical activity with cardiac death and all-cause mortality after ICD or CRT-D implantation.

OBJECTIVE: To evaluate the association of longitudinal changes in physical activity (PA) with long-term outcomes after implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) implantation. METHODS: Patients with ICD/CRT-D implantation from SUMMIT registry were retrospectively analyzed. Accelerometer-derived PA changes over 12 months post implantation were obtained from the archived home monitoring data. The primary endpoints were cardiac death and all-cause mortality. The secondary endpoints were the first ventricular arrthymia (VA) and first appropriate ICD shock. RESULTS: In 705 patients, 446 (63.3%) patients showed improved PA over 12 months after implantation. During a mean 61.5-month follow-up duration, 99 cardiac deaths (14.0%) and 153 all-cause deaths (21.7%) occurred. Compared to reduced/unchanged PA, improved PA over 12 months could result in significantly reduced risks of cardiac death (improved PA ≤ 30 min: hazard ratio (HR) = 0.494, 95% CI: 0.288-0.848; > 30 min: HR = 0.390, 95% CI: 0.235-0.648) and all-cause mortality (improved PA ≤ 30 min: HR = 0.467, 95%CI: 0.299-0.728; > 30 min: HR = 0.451, 95% CI: 0.304-0.669). No differences in the VAs or ICD shocks were observed across different groups of PA changes. PA changes can predict the risks of cardiac death only in the low baseline PA group, but improved PA was associated with 56.7%, 57.4%, and 62.3% reduced risks of all-cause mortality in the low, moderate, and high baseline PA groups, respectively, than reduced/unchanged PA. CONCLUSIONS: Improved PA could protect aganist cardiac death and all-cause mortality, probably reflecting better clinical efficacy after ICD/CRT-D implantation. Low-intensity exercise training might be encouraged among patients with different baseline PA levels.

The value of serum metabolomics analysis in predicting the response to cardiac resynchronization therapy.

OBJECTIVE: To construct a prediction model based on metabolic profiling for predicting the response to cardiac resynchronization therapy (CRT). METHODS: Peripheral venous (PV) and coronary sinus (CS) blood samples were collected from 25 patients with heart failure (HF) at the time of CRT implantation, and PV blood samples were obtained from ten healthy controls. The serum samples were analyzed by liquid chromatography-mass spectrometry (LC-MS). As per the clinical and echocardiographic assessment at the 6-month follow-up, the HF patients were categorized as CRT responders and non-responders. RESULTS: HF patients had altered serum metabolomic profiles that were significantly different from those of the healthy controls. Differential metabolites were also observed between CRT responders and non-responders. A prediction model for CRT response (CRT-Re) was constructed using the concentration levels of the differential metabolites, L-arginine and taurine. The optimal cutoff value of the CRT-Re model was found to be 0.343 by ROC analysis (sensitivity, 88.2%; specificity, 87.5%; Area under curve (AUC) = 0.897, P = 0.002). The concentration levels of the differential metabolites, L-arginine and lysyl-gamma-glutamate, in PV serum were significantly correlated with that in CS serum (r = 0.945 and 0.680, respectively, all P < 0.001). CONCLUSIONS: Our results suggest that serum-based metabolic profiling may be a potential complementary screening tool for predicting the outcome of CRT.

The roles of the Q (q) wave in lead I and QRS frontal axis for diagnosing loss of left ventricular capture during cardiac resynchronization therapy.

INTRODUCTION: Loss of left ventricular (LV) capture may lead to deterioration of heart failure in patients with cardiac resynchronization therapy (CRT). Recognition of loss of LV capture in time is important in clinical practice. METHODS AND RESULTS: A total of 422 electrocardiograms were acquired and analyzed from 53 CRT patients at 8 different pacing settings (LV only, right ventricle [RV] only, biventricular [BV] pacing with LV preactivation of 60, 40, 20, and 0 milliseconds and RV preactivation of 20 and 40 milliseconds). A modified Ammann algorithm by adding a third step-presence of Q (q, or QS) wave-to the original 2-step Ammann algorithm and a QRS axis shift method were devised to identify the loss of LV capture. The accuracy of modified Ammann algorithm was significantly higher than that of Ammann algorithm (78.9% vs. 69.1%, P < 0.001). The accuracy of the axis shift method was 66.4%, which was significantly lower than the modified Ammann algorithm (P < 0.001) and similar to the original one (P = 0.412). However, in the ECGs with QRS axis shift, 96.8% were correctly classified. LV preactivation or simultaneous BV activation and LV lead positioned in nonposterior or noninferior wall could elevate the accuracies of the modified Ammann algorithm and the QRS axis shift method. CONCLUSIONS: The accuracy of the modified Ammann algorithm is greatly improved. The QRS axis shift method can help diagnose LV capture. The LV preactivation, or simultaneous BV activation and LV lead positioned in nonposterior or noninferior wall can increase the diagnostic power of the modified Ammann algorithm and QRS axis shift method.

Reduction of atrial fibrillation in remotely monitored pacemaker patients: results from a Chinese multicentre registry.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Three-dimensional speckle tracking echocardiography for the assessment of left ventricular function and mechanical dyssynchrony.

OBJECTIVE: Evaluation of left ventricular (LV) function and dyssynchrony is of vital importance. A newly-developed three-dimensional (3D) speckle tracking echocardiography (STE) has the potential to circumvent limitations of two-dimensional STE. Our study was to evaluate LV function and dyssynchrony by 3D-STE. METHODS AND RESULTS: Fifty-two non-ischaemic dilated cardiomyopathy patients (DCM) with complete left bundle-branch block and 55 healthy subjects were enrolled. Of these patients, 24 underwent cardiac resynchronization therapy (CRT). 3D-STE was performed before and 1 month after CRT. We measured 3D (3DS), longitudinal (LS), circumferential (CS) and radial (RS) strain of the LV. LV dyssynchrony was evaluated by the standard deviation of time to peak negative value of 3D strain (3DS-SD) and time to reach the minimum regional volume of 16 segments (SDI) related to the heart cycle. DCM patients had significantly lower global 3DS (-17.12 +/- 6.70% vs -38.38 +/- 4.28%, P < 0.01), significantly greater 3DS-SD (11.11 +/- 5.14% vs 4.04 +/- 1.43%, P < 0.01) and SDI (9.69 +/- 4.82% vs 4.23 +/- 1.33%, P < 0.01) than normal volunteers. 3DS, LS, CS, RS had an excellent correlation with LV ejection fraction (LVEF) (r2 = -0.94, -0.91, -0.93, 0.89, respectively, P < 0.01 for all). 3DS-SD correlated well with SDI (ICC = 0.85). For mild, moderate and severe systolic dysfunction, 3DS-SDs were 4.56 +/- 1.53%, 9.87 +/- 2.58%, and 14.55 +/- 4.71%, respectively (P < 0.01) and SDIs were 4.46 +/- 1.27%, 8.19 +/- 2.35%, and 12.83 +/- 4.87%, respectively (P < 0.01), but independently of QRS width. After CRT therapy, global 3DS (-13.12 +/- 2.63% to -14.06 +/- 2.53%, P = 0.025), 3DS-SDs (12.99 +/- 3.92% to 11.53 +/- 4.53%, P = 0.015) and SDIs (10.85 +/- 3.74% to 9.50 +/- 4.63%, P = 0.013) were markedly improved. CONCLUSION: When image quality is optimal, 3D STE seems to be a promising approach assessing LV function and dyssynchrony.