Yangang Su

Is Right Ventricular Outflow Tract Pacing Superior to Right Ventricular Apex Pacing in Patients with Normal Cardiac Function

Whether right ventricular outflow tract (RVOT) pacing is superior to right ventricular apex (RVA) pacing in terms of ventricular synchrony, cardiac function, and remodeling in patients with normal cardiac function is still unknown.

Meta-analysis of randomized controlled trials comparing isolated left ventricular and biventricular pacing in patients with chronic heart failure.

Cardiac resynchronization therapy (CRT) has been mostly achieved by biventricular pacing (BVP) in patients with chronic heart failure (CHF), although it can also be provided by left ventricular pacing (LVP). The superiority of BVP over LVP remains uncertain. The present meta-analysis of randomized controlled trials was performed to compare the effects of LVP to BVP in patients with CHF. Outcomes analyzed included clinical status (6-minute walk distance, peak oxygen consumption, quality of life, New York Heart Association class), LV function (LV ejection fraction), and LV remodeling (LV end-systolic volume). Five trials fulfilled criteria for inclusion in analysis, which included 574 patients with CHF indicated for CRT. After a midterm follow-up, pooled analysis demonstrated that LVP resulted in similar improvements in 6-minute walk distance (weighted mean difference [WMD] 11.25, 95% confidence interval [CI] -12.39 to 34.90, p = 0.35), quality of life (WMD 0.34, 95% CI -3.72 to 4.39, p = 0.87), peak oxygen consumption (WMD 1.00, 95% CI -0.84 to 2.85, p = 0.29), and New York Heart Association class (WMD -0.19, 95% CI -0.79 to 0.42, p = 0.54). There was a trend toward a superiority of BVP over LVP for LV ejection fraction (WMD 1.28, 95% CI -0.11 to 2.68, p = 0.07) and LV end-systolic volume (WMD -5.73, 95% CI -11.86 to 0.39, p = 0.07). In conclusion, LVP achieves similar improvement in clinical status as BVP in patients with CHF, whereas there was a trend toward superiority of BVP over LVP for LV reverse modeling and systolic function.

Relationships between paced QRS duration and left cardiac structures and function.

Background — In patients with congestive heart failure, QRS duration (QRSd) is correlated with left ventricular (LV) ejection fraction (LVEF), ventricular dyssynchrony and patients’ prognosis. However, little is known about the relationships between paced QRS duration (pQRSd) to cardiac structures and function and ventricular dyssynchrony in patients with chronic right ventricular apical (RVA) pacing, which were investigated in this study. Methods — Seventy patients implanted with DDD(R) pacemaker for high- or third-degree atrioventricular block were enrolled to study pQRSd and echocardiographic variables, including aortic root dimension (AO), left atrial dimension (LAD), LV end-systolic dimension (LVDs), LV end-diastolic dimension (LVDd), interventricular septum thickness (IVST), LV posterior wall thickness (LVPWT), LVEF, interventricular mechanical delay (IVMD), systolic asynchrony index (Ts-SD) and septal-tolateral delay.The relationships between pQRSd and such variables were examined. Results — The pQRSd correlated positively with LVDd (r = 0.3166, P < 0.05), LVDs (r = 0.3741, P < 0.05), LAD (r = 0.5848, P < 0.01), IVST (r = 0.2925, P < 0.05), and negatively with LVEF (r = – 0.3037, P < 0.05). No significant correlations were found between pQRSd and AO, LVPWT, IVMD, Ts-SD and septal-to-lateral delay (all P > 0.05). There was no significant correlation between LVEF and IVMD, Ts-SD, septal-to-lateral delay (P > 0.05). However, IVMD, Ts-SD and septal-to-lateral delay were greater in patients with low LVEF than in patients with normal LVEF (P < 0.05). A cut-off value for pQRSd of 180 ms had a sensitivity of 85.71% and a specificity of 66.67% to detect left atrial dilation. Conclusion — pQRSd is correlated with left cardiac structures and LV systolic function. pQRSd ≥ 180 ms indicates left atrial dilation.There is no correlation between pQRSd and ventricular dyssynchrony.

Value of the paced QRS duration.

BACKGROUND The value for paced QRS duration (pQRSd) to detect left ventricular (LV) dysfunction in right ventricular apex (RVA)-paced patients has not been evaluated. METHODS AND RESULTS A total of 272 RVA-paced patients, including 99 with LV systolic dysfunction (LVSD) and 173 without LVSD, were enrolled in this study. The pQRSd, echocardiographic variables, and plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were measured. Relationships between pQRSd and echocardiographic variables, NT-proBNP levels, and New York Heart Association (NYHA) functional classification were analyzed. pQRSd was correlated with LV end-diastolic and end-systolic dimensions (beta = 1.59 and 1.54, respectively; all P < .001), NT-proBNP levels (beta = 12.98, P < .001) and LV ejection fraction (beta = -109.25, P < .001). There was a stepwise increase in pQRSd with increasing NYHA Class (all P < .001). The pQRSd cutoff value of 200 ms, derived from the receiver operator characteristic curve, had sensitivity of 71.72% and specificity of 86.71% to detect LVSD. pQRSd >or= 240 ms gave a positive predictive value of 100%, whereas <180 ms excluded >97.3% of patients with LVSD. CONCLUSIONS In RVA-paced patients, pQRSd is correlated with left ventricular structures and function and pQRSd of 200 ms is a satisfactory cutoff value in terms of sensitivity and specificity for detecting LVSD.

Native and Paced QRS Duration in Right Ventricular Apex Paced Patients

BACKGROUND The value between paced QRS duration (pQRSd) and native QRS duration (nQRSd) in paced population has not been compared. The relation between nQRSd and pQRSd remains undefined now. METHODS AND RESULTS A total of 310 right ventricular apex (RVA) paced patients were enrolled. The correlation coefficients between nQRSd and pQRSd to left ventricular (LV) dimensions and ejection fraction (LVEF) were calculated and then compared. The association between pQRSd and nQRSd was examined. pQRSd was better correlated with LVDD, LVDS, and LVEF than nQRSd in all patients or patients with no intraventricular conduction block (NIVCB, n = 136) or complete right bundle-branch block (CRBB, n = 86) (all P < .01). pQRSd was positively correlated with nQRSd in NIVCB, CRBB, and complete left bundle-branch block (CLBB, n = 45) patients (r = 0.408, 0.465, and 0.766, respectively; all P < .001). However, pQRSd was not different between NIVCB, CRBB, and CLBB patients (P > .05) after adjusting for LVEF and LV dimensions. CONCLUSIONS pQRSd is superior to nQRSd in terms of reflecting LV structures and function in RVA-paced patients. Bundle branch block (BBB) has no significant effect on pQRSd and thus further studies are needed to clarify whether BBB is an independent risk factor for the development of heart failure after RVA pacing.

Effect of Cardiac Resynchronization Therapy on Myocardial Fibrosis and Relevant Cytokines in a Canine Model with Experimental Heart Failure

Though cardiac resynchronization therapy (CRT) has now proved to be effective on cardiac reverse remodeling, data on the underlying molecular changes are limited. The present study aims to investigate the expression of cytokines concerning myocardial fibrosis in dyssynchronous heart failure (HF) and the potential benefits of CRT.

A new score system for predicting response to cardiac resynchronization therapy

BACKGROUND The aim of this study was to establish a score system derived from clinical, echocardiographic and electrocardiographic indexes and evaluate its clinical value for cardiac resynchronization therapy (CRT) patient selection. METHODS Ninety-three patients receiving CRT were enrolled. A patient selection score system was generated by the clinical, echocardiographic and electrocardiographic parameters achieving a significant level by univariate and multivariate Cox regression model. The positive response to CRT was a left ventricular end systolic volume decrease of ≥ 15% and not reaching primary clinical endpoint (death or re-hospitalization for heart failure) at the end of follow-up. RESULTS Thirty-nine patients were CRT non-responders (41.94%) and 54 were responders (58.06%). A 4-point score system was generated based on tricuspid annular plane systolic excursion (TAPSE), longitudinal strain (LS), and complete left bundle branch block (CLBBB) combined with a wide QRS duration (QRSd). The sensitivity and specificity for prediction of a positive response to CRT at a score > 2 were 0.823 and 0.850, respectively (AUC: 0.92295% CI 0.691-0.916, p< 0.001). CONCLUSIONS A patient selection score system based on the integration of TAPSE, LS and CLBBB combined with a wide QRSd can help to predict positive response to CRT effectively and reliably.

Thromboembolic Events During the Perioperative Period in Patients Undergoing Permanent Pacemaker Implantation

Thromboembolism (TE) is one of the most serious complications after pacemaker implantation. It has been demonstrated that several patient characteristics and different pacing modes are related to an increased risk of TE events during long‐term follow‐up.

Electro-echocardiographic Indices to Predict Cardiac Resynchronization Therapy Non-response on Non-ischemic Cardiomyopathy

Cardiac resynchronization therapy (CRT) threw lights on heart failure treatment, however, parts of patients showed nonresponse to CRT. Unfortunately, it lacks effective parameters to predict CRT non-response. In present study, we try to seek effective electro-echocardiographic predictors on CRT non-response. This is a retrospective study to review a total of 227 patients of dyssynchronous heart failure underwent CRT implantation. Logistic analysis was performed between CRT responders and CRT non-responders. The primary outcome was the occurrence of improved left ventricular ejection fraction 1 year after CRT implantation. We concluded that LVEDV > 255 mL (OR = 2.236; 95% CI, 1.016–4.923) rather than LVESV > 160 mL (OR = 1.18; 95% CI, 0.544–2.56) and TpTe/QTc > 0.203 (OR = 5.206; 95% CI, 1.89–14.34) significantly predicted CRT non-response. Oppositely, S wave > 5.7 cm/s (OR = 0.242; 95% CI, 0.089–0.657), E/A > 1 (OR = 0.211; 95% CI, 0.079–0.566), E’/A’ > 1 (OR = 0.054; 95% CI, 0.017–0.172), CLBBB (OR = 0.141; 95% CI, 0.048–0.409), and QRS duration >160 ms (OR = 0.52; 95% CI, 0.305–0.922) surprisingly predicted low-probability of CRT non-response.

Impact of interlead distance on immediate and mid-term response to cardiac resynchronization therapy

Abstract Objectives. It is currently recommended that the left ventricular (LV) lead be placed at the posterolateral or lateral wall of heart during cardiac resynchronization therapy (CRT). The aim of our study is to evaluate the influence of interlead distance on immediate and mid-term response to CRT with altered right ventricular (RV) pacing site. Design. A total of 35 consecutive patients underwent CRT for standard indications. RV pacing site was altered from RV outflow tract (RVOT) to RV apex (RVA) in the course of implantation, permitting assessment of a “poorer response” and a “better response” site based on intraprocedural aortic velocity time integral (aVTI). LV–RV interlead distances were compared between these sites during operation. We also made a comparison of the interlead distances between responders and non-responders 6 months after CRT. Results. In the process of CRT implantation, the better response site showed significantly larger interlead distance (16.5 ± 4.4 cm vs.12.4 ± 5.6 cm, p = 0.001) as well as its vertical component (9.8 ± 4.8 cm vs. 4.3 ± 2.8 mm, p = 0.001) on lateral fluoroscopy view as compared with the poorer response site. Furthermore, RVA proved more likely to be the “better response” site than RVOT (91% vs. 9%, p = 0.001). At 6-month -up, responders demonstrated larger direct interlead distance (18.1 ± 4.5 cm vs. 14.8 ± 3.5 cm, p = 0.011) and horizontal interlead distance (14.1 ± 6.6 cm vs. 8.3 ± 6.1 cm, p = 0.004) on the lateral radiograph in comparison with non-responders with great significance. Conclusions. Larger interlead distance on lateral fluoroscopy view is associated with more favorable immediate and mid-term response to CRT. Use of these findings may help to maximize the benefit derived from CRT.