Acute and Chronic Changes and Predictive Value of Tpeak-Tend for Ventricular Arrhythmia Risk in Cardiac Resynchronization Therapy Patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Prolongation of the Tpeak-Tend (TpTe) interval as a measurement of transmural dispersion of repolarization (TDR) is an independent risk factor for chronic heart failure mortality. However, the cardiac resynchronization therapy's (CRT) effect on TDR is controversial. Therefore, this study aimed to evaluate CRTs acute and chronic effects on repolarization dispersion. Furthermore, we aimed to investigate the relationship between TpTe changes and ventricular arrhythmia.</p><p><b>METHODS</b>The study group consisted of 101 patients treated with CRT-defibrillator (CRT-D). According to whether TpTe was shortened, patients were grouped at immediate and 1-year follow-up after CRT, respectively. The echocardiogram index and ventricular arrhythmia were observed and compared in these subgroups.</p><p><b>RESULTS</b>For all patients, TpTe slightly increased immediately after CRT-D implantation, and then decreased at the 1-year follow-up (from 107 ± 23 to 110 ± 21 ms within 24 h, to 94 ± 24 ms at 1-year follow-up, F = 19.366,P< 0.001). No significant difference in the left ventricular reverse remodeling and ventricular tachycardia/ventricular fibrillation (VT/VF) episodes between the TpTe immediately shortened and TpTe immediately nonshortened groups. However, patients in the TpTe at 1-year shorten had a higher rate of the left ventricular (LV) reverse remodeling (65% vs. 44%, χ2 = 4.495, P = 0.038) and less VT/VF episodes (log-rank test, χ2 = 10.207, P = 0.001) compared with TpTe 1-year nonshortened group. TpTe immediately after CRT-D independently predicted VT/VF episodes at 1-year follow-up (hazard ratio [HR], 1.030; P = 0.001).</p><p><b>CONCLUSIONS</b>Patients with TpTe shortened at 1-year after CRT had a higher rate of LV reverse remodeling and less VT/VF episodes. The acute changes of TpTe after CRT have minimal value on mechanical reverse remodeling and ventricular arrhythmia.</p>

Optimized Fluoroscopy Setting and Appropriate Project Position Can Reduce X-ray Radiation Doses Rates during Electrophysiology Procedures / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Nonfluoroscopic three-dimensional electroanatomical system is widely used nowadays, but X-ray remains indispensable for complex electrophysiology procedures. This study aimed to evaluate the value of optimized parameter setting and different projection position to reduce X-ray radiation dose rates.</p><p><b>METHODS</b>From June 2013 to October 2013, 105 consecutive patients who underwent complex ablation were enrolled in the study. After the ablation, the radiation dose rates were measured by two different settings (default setting and optimized setting) with three projection positions (posteroanterior [PA] projection; left anterior oblique [LAO] 30° projection; and LAO 45° projection). The parameter of preset voltage, pulse width, critical voltage, peak voltage, noise reduction, edge enhancement, pulse rate, and dose per frame was modified in the optimized setting.</p><p><b>RESULTS</b>The optimized setting reduced radiation dose rates by 87.5% (1.7 Gy/min vs. 13.6 Gy/min, P < 0.001) in PA, 87.3% (2.5 Gy/min vs. 19.7 Gy/min, P < 0.001) in LAO 30°, 85.9% (3.1 Gy/min vs. 22.1 Gy/min, P < 0.001) in LAO 45°. Increase the angle of projection position will increase the radiation dose rate.</p><p><b>CONCLUSIONS</b>We can reduce X-ray radiation dose rates by adjusting the parameter setting of X-ray system. Avoiding oblique projection of large angle is another way to reduce X-ray radiation dose rates.</p>

Home monitoring system improves the detection of ventricular arrhythmia and inappropriate shock / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The impact of home monitoring system in the early detection of ventricular arrhythmia and inappropriate shock in daily work is not clear. The aim of this study was to investigate the impact of home monitoring system on the early detection of ventricular arrhythmia and inappropriate shock in daily clinical practice.</p><p><b>METHODS</b>Cases of implantable cardioverter defibrillator (ICD) implantation with or without the home monitoring system from June 2010 to October 2011 at our center were reviewed. Follow-up was scheduled after implantation. Data relating to the home monitoring ICD were retrieved using a remote transmitter system. Data relating to the other devices were obtained during scheduled follow-up or unscheduled visits.</p><p><b>RESULTS</b>Our study involved 69 patients (mean age (68.4 ± 17.6) years, 64.3% males, 26 in the home monitoring group vs. 43 in the non-home monitoring group). In all, 561 ventricular arrhythmia episodes were detected in 17 patients (39.5%) in the non-home monitoring group: 495 episodes were ventricular tachycardia and 66 episodes were ventricular fibrillation; among these, 476 episodes of ventricular tachycardia and 45 episodes of ventricular fibrillation were appropriately diagnosed (96.1% and 68.2%, respectively). In the home monitoring group, 389 ventricular arrhythmia episodes were transmitted by the home monitoring system in nine patients (34.6%): 348 ventricular tachycardia episodes and 41 ventricular fibrillation episodes. Device detection was appropriate in 348 ventricular tachycardia episodes (100.0%) and 36 ventricular fibrillation episodes (87.8%). The home monitoring group showed a higher appropriate detection rate of ventricular tachycardia (P < 0.01) and ventricular fibrillation (P = 0.02). The proportion of inappropriate shock was comparable in the two groups (6/11 in the non-home monitoring group vs. 1/7 in the home monitoring group; P = 0.08).</p><p><b>CONCLUSIONS</b>The home monitoring ICD was able to provide information relating to inappropriate detection and shock earlier than conventional devices. It proved to be a reliable tool and has a strong potential to provide greater reaction time in the case of inappropriate shock.</p>

Improvement of P-wave dispersion is associated with a lower incidence of atrial fibrillation after cardiac resynchronization therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>P-wave dispersion (PWD) is a useful predictor of paroxysmal atrial fibrillation (AF). The effect of cardiac resynchronization therapy (CRT) on PWD and the prognostic implications of the improvement in PWD remain undefined. The aim of the study was to explore the clinical significance of the improvement of PWD after CRT.</p><p><b>METHODS</b>Electrocardiographic studies were performed before and three months after CRT in 81 patients (57 men and 24 women; age (60.5 ± 11.2) years) with standard CRT indication but no history of AF. A significant improvement of PWD (PWD responder) was defined as a relative decrease ≥ 20% from baseline PWD. The primary endpoints were new-onset AF detected by electrocardiogram (ECG) or CRT.</p><p><b>RESULTS</b>After (30.6 ± 7.5) months of follow-up, PWD responders (n = 43) had a significantly lower incidence of AF than did PWD nonresponders, 12% vs. 29% (P < 0.001). In Cox proportional hazard analysis, PWD responders was the only predictor of lower risk of new-onset AF (HR 0.33, 95% confidence interval 0.12 - 0.96, P = 0.033).</p><p><b>CONCLUSION</b>Improvement of P-wave dispersion after CRT was associated with a lower incidence of AF, which may be related to the significant improvement in left ventricular systolic function and the reverse modeling of the left atrium.</p>

Improved approach to atrial septum puncture: experience in 539 cases / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The transseptal puncture technique has been widely used in therapeutic left atrium catheterization. But this technique may lead to some life-threatening complications. It can not be used widely because it is restricted by economy and deferring the transseptal puncture procedure. The aim of this study was to introduce a simple and safe transseptal puncture procedure.</p><p><b>METHODS</b>The distal of coronary sinus (CS) electrode was positioned close to the lateral margin of heart, which was about at 3 o'clock at left anterior oblique (LAO) 30° referred to whole cardiac profile. It was then used as the marker for the level of fossa ovalis at posterior-anterior projection to guide the pull of transseptal needle. The midpoint between the distal CS and the posterior margin of heart at right anterior oblique (RAO) 45° view was considered as the location of fossa ovalis. Once the puncture was succeeded, the guidewire was introduced to the left superior pulmonary vein via puncture sheath after the needle was retrieved. The end of outer sheath was introduced into left atrium with the protection of guidewire. It was applied in 539 patients (316 male, 223 female; (53 ± 16) years old) who underwent catheter ablation of atrial fibrillation or left-sided atrioventricular accessory pathway.</p><p><b>RESULTS</b>This transseptal approach reached 100.0% success and was succeeded in 98.9% with the first attempt. The first attempt puncture was aborted due to greater resistance to needle advancement or smaller needle curve in six patients. However, the second attempts were all succeeded after the needle curve was reshaped. There was no tamponade and embolism occurred.</p><p><b>CONCLUSION</b>The atrial septum puncture approach using the location of distal CS electrode as important marker and the guidewire for protection when sending outer sheath into left atrium is reliable and safe.</p>

Single center experience with intrathoracic impedance monitoring / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The Medtronic InSync Sentry is the first available cardiac resynchronization therapy defibrillator (CRT-D) which can monitor fluid status by measuring intrathoracic impedance. This study was designed to observe the effectiveness of intrathoracic impedance monitoring on detecting aggravation of heart failure.</p><p><b>METHODS</b>We retrospectively analyzed the clinical data of 14 consecutive patients. Patients were regularly followed up every 3 - 6 months after the implantation. At each visit, interrogation of the device was done. Patients were instructed to inform the researcher on hearing the device alert, and to take extra 40 milligrams of furosemidum if they had aggravated symptoms later. If the symptoms could not be relieved, they were asked to see a doctor. Data about heart failure hospitalization were collected from the medical record.</p><p><b>RESULTS</b>During 18 - 48 months follow-up, a total of 7 patients encountered 28 alert events. On one hand, alert events appeared before all deteriorated symptoms and heart failure hospitalizations. On the other hand, there were 23 alerts followed by deterioration of heart failure symptoms, and 2 alerts related to 2 hospitalizations caused by pulmonary infection in one patient. Only 5 patients were hospitalized 10 times for deterioration of cardiac function.</p><p><b>CONCLUSION</b>The function of intrathoracic impedance monitoring is reliable in predicting deterioration of heart failure.</p>

Potential predictors of non-response and super-response to cardiac resynchronization therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Although cardiac resynchronization therapy (CRT) is already an established treatment, the characteristics of patients who have an excellent response to CRT and those who get no benefit remain to be determined. The purpose of this study was to search for potential predictors of both non-response and super-response to CRT.</p><p><b>METHODS</b>Seventy-six consecutive patients who received CRT treatment were divided into group A (non-responders), group C (super-responders) and group B (responders exclusive of super-responders). Student's t test, Mann-Whitney test, Logistic regression and receiver operating characteristic curve were employed to identify potential predictors among the patients' demographic characteristics, clinical features, several electrocardiographic parameters before and after CRT implantation, and their pre-implant echocardiographic parameters.</p><p><b>RESULTS</b>Group A had the lowest 3-month left ventricular ejection fraction (LVEF). Group C had the smallest pre-implant left ventricular end-diastolic dimension (LVEDD), the shortest post-implant QRS duration, the smallest 3-month LVEDD and the highest 3-month LVEF. In addition, there was a trend of gradual change in percent of left bundle branch block, severity of pre-implant mitral regurgitation, pre-implant QRS dispersion, post-implant QRS duration as well as post-implant QRS dispersion from group A to group B and from group B to group C. Multivariable Logistic analysis revealed that only pre-implant LVEDD could predict CRT super-response. A pre-implant LVEDD of 68.5 mm was the cut-off value that identified super-responders with 87.5% sensitivity and 79.7% specificity. A pre-implant LVEDD of 62.5 mm identified super-responders with 50.0% sensitivity and 89.8% specificity.</p><p><b>CONCLUSIONS</b>Predictors of a CRT non-response remain unclear at present. But it is credible that patients with a smaller left ventricle would have a better chance to become super-responders to CRT.</p>

Usefulness of previsualization of the cardiac venous system by 64-slice computed tomography in patients with heart failure underwent cardiac resynchronization therapy / 中华心血管病杂志

<p><b>OBJECTIVE</b>To evaluate the value of 64-slice computed tomography (MDCT) in previsualization the cardiac veins anatomy before the implantation of cardiac resynchronization therapy (CRT).</p><p><b>METHODS</b>The 64-slice CT scans of 21 patients [10 men, age (61.6 ± 9.7) years] were obtained and analyzed before the implantation of CRT. Retrograde coronary venography was performed during intraoperational fluoroscopy. The coronary sinus (CS) and the main tributaries were measured.</p><p><b>RESULTS</b>Similar images to those obtained during the CRT implantation procedure were obtained by MDCT in 71% of the patients. The coronary sinus was clearly visible in all cases, the measured ostium was (12.1 ± 4.2) mm, and the angle between the CS and the vertical plane was (99 ± 12) degrees. In 90% of patients, at least one vein was clearly visible in the target area. Among the target veins, the posterolateral vein was visible in most cases (86%) and the lateral vein was visible in 48% of the patients.</p><p><b>CONCLUSION</b>MDCT is an effective and noninvasive method for previsualization of the cardiac venous system, which may facilitate optimal left ventricular lead positioning for CRT implantation.</p>

Decrease of plasma N-terminal pro beta-type natriuretic peptide as a predictor of clinical improvement after cardiac resynchronization therapy for heart failure / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>N-terminal pro beta-type natriuretic peptide (NT pro BNP) has been shown to predict the prognosis and could guide the treatment of heart failure. We aimed to investigate the values of NT pro BNP in predicting the clinical response to cardiac resynchronization therapy (CRT).</p><p><b>METHODS</b>A total of 44 patients with chronic heart failure (34 male and 10 female, mean age of (58 +/- 13) years, New York Heart Association (NYHA) class 3.3 +/- 0.5, QRS duration (150 +/- 14) milliseconds) who underwent successful implantation of a CRT system were enrolled in this study. Pharmacotherapy remained stable during the first 3 months of follow-up. Plasma levels of NT pro BNP were evaluated before and 3 months after implantation. Clinical, echocardiographic and exercise parameters were monitored at each clinical visit after CRT implantation. Receiver operating characteristic analysis and a paired t test were performed to analyze the data.</p><p><b>RESULTS</b>After a mean of (16.3 +/- 5.5) months of follow-up, 11 nonresponders were identified. CRT resulted in a significant reduction in NT pro BNP ((1.70 +/- 1.28) vs (1.07 +/- 0.88) pmol/ml, P < 0.001) in responders. Percentage change in NT pro BNP level (DeltaBNP%) was a statistically significant predictor of long term clinical improvement at 3 months of follow-up.</p><p><b>CONCLUSIONS</b>DeltaBNP% from baseline to 3 months of follow-up is a predictor of long term response to CRT. NT pro BNP may be a simple method for monitoring the effects of CRT.</p>