Right ventricular septal pacing preserves global left ventricular longitudinal function in comparison with apical pacing: analysis of speckle tracking echocardiography

The effect of right ventricle septal pacing versus apical pacing in dual-chamber pacemakers on patients' anxiety and depression: a one-year follow-up study

BACKGROUND

Anxiety and depression are potentially harmful outcomes of permanent cardiac pacemakers. Dual-chamber P.P.M. is frequently used to treat life threatening bradycardia. The study aims to estimate the effect of the right ventricular PM lead position on recipients' anxiety and depression before, 6 months, and 1 year after implantation.

RESULTS

A statistically significant correlation was discovered between the studied groups regarding HADS depression score after 6 months (p 0.013) and 1 year (p 0.013). A statistically non-significant difference was found among the studied groups at any point of time regarding baseline (p 0.063), after 6 months (p 0.054), or after 1 year (p 0.099). Significance was found between HADS anxiety score (p 0.015) or depression score after 1 year and the incidence of complications (p 0.001).

CONCLUSIONS

A strong relationship was found between the level of depression and the R.V. site of implantation, as patients with the apical group had higher levels of depression post-implantation. The septal position has less stress and depression on the patient's well-being than the apical one.

Mid-term outcomes of delivery catheter-based and stylet-based right ventricular septal pacing: Follow-up results from a multicenter, prospective, randomized study

Background

The Mt FUJI study was a multicenter, prospective, randomized, single-blind, controlled trial comparing delivery catheter-based and stylet-based right ventricular (RV) lead placement at the RV septum. This study extended the follow-up duration to 1 year after implantation.

Methods

Seventy patients with pacemaker indications for atrioventricular block were randomly assigned to the delivery catheter and stylet groups. We compared the mid-term efficacy and safety between the two groups at 1 year after implantation. The primary outcome was the change in the left ventricular ejection fraction (LVEF), and the secondary outcomes were changes in brain natriuretic peptide (BNP) levels, lead parameters, paced QRS duration, and the incidence of adverse events.

Results

At the 1-year follow-up, no significant differences were observed in the changes in the LVEF (+1.0% ± 8.6% vs. +3.1% ± 8.1%, p = .332), BNP levels (+8.0 [-11.1, 26.5] pg/mL vs. -8.7 [-15.3, 13.2] pg/mL, p = .193), or lead performance between the delivery catheter and stylet groups. The QRS duration was significantly shorter in the delivery catheter group than in the stylet group (128 ± 23 ms vs. 146 ± 17 ms, p < .001). All-cause death, hospitalization for heart failure, new development of atrial fibrillation, and pacing-induced cardiomyopathy occurred in seven patients in the delivery catheter group and five in the stylet group.

Conclusion

The delivery catheter system was similarly useful and safe compared to the stylet system in the mid-term follow-up from the Mt FUJI trial. Further long-term evaluations are warranted.

Impact of right ventricular lead position on left ventricular functions and early remodeling in permanent single- and dual-chamber pacemakers

BACKGROUND

Right ventricular (RV) apical pacing can induce both interventricular dyssynchrony and intraventricular dyssynchrony. Mechanical dyssynchrony after long-term RV apical pacing is associated with reduced left ventricular (LV) systolic function and deterioration in functional capacity.

AIM

We aimed to identify the short-term effects of the pacemaker RV lead position on remodeling of LV systolic functions.

PATIENTS AND METHODS

The study included 30 patients who presented with an indication of permanent pacing and who underwent permanent single- or dual-chamber pacemaker insertion: 15 patients with RV apical pacing (RV apex), and 15 patients with non-apical pacing (mid-septal). The two-dimensional (2D) speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and dyssynchrony evaluation before pacemaker implantation and after a 3-month follow-up.

RESULTS

At the 3‑month follow-up, post-pacing 2D speckle tracking echocardiography revealed impairment of global longitudinal strain in all patients and intraventricular dyssynchrony was significantly increased in the apical location compared with the non-apical location (radial dyssynchrony: 108.67 ± 11.68 ms vs. 80.53 ± 8.17 ms, p < 0.001) with a greater difference (50.53 ± 13.30 ms) in the apical location than in the non-apical location (29.87 ± 6.64 ms, p < 0.001).

CONCLUSION

In the short-term follow-up, 2D speckle tracking echocardiography showed more radial dyssynchrony in the apical location than in the non-apical location of RV lead. The RV septal pacing is a better alternative in terms of less dyssynchrony compared to RV apical pacing. Older age, higher percentage of pacing, and device type are prognostic factors for development of pacemaker-induced cardiomyopathy.

Comparison of delivery catheter-based and stylet-based right ventricular lead placement at the right ventricular septum under fluoroscopic guidance judged by cardiac CT (Mt. FUJI): a study protocol for the Mt. FUJI randomised controlled trial

INTRODUCTION

Pacing-induced cardiomyopathy occasionally occurs in patients undergoing pacemaker implantation. Although compared with right ventricular (RV) apical pacing, RV septal pacing can attenuate left ventricular dyssynchrony; the success rate of lead placement on the RV septum using the stylet system is low. Additionally, no randomised controlled trial has addressed the issue regarding the accuracy of RV lead placement on the RV septum using the stylet and delivery catheter systems. This study hypothesises that a newly available delivery catheter system can improve the accuracy of RV lead placement on the RV septum.

METHODS AND ANALYSIS

In a multicentre, prospective, randomised, single-blind, controlled trial, 70 patients with pacemaker indication owing to atrioventricular block will be randomised to either the delivery catheter or stylet group before the pacemaker implantation procedure. The position of the RV lead tip will be assessed using ECG-gated cardiac CT in all patients within 4 weeks after pacemaker implantation. Lead tip positions are classified into three groups: (1) RV septum, (2) anterior/posterior edge of the RV septal wall and (3) RV free wall. The primary endpoint will be the success rate of RV lead tip placement on the RV septum, which will be evaluated using cardiac CT.

ETHICS AND DISSEMINATION

This study will be conducted according to the stipulations of the Helsinki Declaration and the institutional review board of Hamamatsu University School of Medicine. The results of the study will be disseminated at several research conferences and will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

jRCTs042200014; Pre-results.

The usefulness of a delivery catheter system for right ventricular "true" septal pacing

Right ventricular (RV) septum is an alternate site for the placement of RV lead tip instead of RV apex. Recent studies have demonstrated that less than half of the RV leads targeted for septal implantation are placed on the RV septum using a conventional stylet system; new guiding catheter systems have become available for RV lead placement. This study aimed to investigate the usefulness of the delivery catheter system in lead placement on the RV septum when compared with the stylet system. We retrospectively evaluated 198 patients who underwent fluoroscopically guided pacemaker implantation with RV leads targeted to be placed in the RV septum and in whom computed tomography was incidentally and subsequently performed. A delivery catheter was used in 16 patients, and a stylet in 182 patients. The primary endpoint of this study was the success rate of RV lead placement on the RV septum. The proportion of RV lead placement on the RV septum was higher in the delivery catheter group than in the stylet group (100% vs. 44%; p < 0.001). In the stylet group, the lead tips were placed at the hinge in 92 cases (51%) and on the free wall in 9 cases (5%). Paced QRS duration was narrower in the delivery catheter group than in the stylet group (128 ± 16 vs. 150 ± 21 ms, p < 0.01). The delivery catheter system designated for pacing leads may aid in selecting RV septal sites and achieve good physiologic ventricular activation.

Determining the thresholds for abnormal left ventricular strains in healthy subjects by echocardiography: a meta-analysis

Background

Left ventricular global longitudinal strain (LVGLS), circumferential strain (LVGCS) and radial strain (LVGRS) are echocardiographic parameters with wide clinical applicability. However, the thresholds for abnormal left ventricular (LV) strains, particularly the lower limits of normal (LLN), are not well established. This meta-analysis determined the mean and LLN of two- (2D) and three-dimensional (3D) LV strain in healthy subjects and factors that influence strain measurements.

Methods

We searched PubMed, Embase and Cochrane databases until 31 December 2019 for studies reporting left ventricular (LV) global strain in at least 50 healthy subjects. We pooled means and LLNs of 2D and 3D LV strain using random-effects models, and performed subgroup and meta-regression analysis for LVGLS.

Results

Forty-four studies were eligible totaling 8,910 subjects. The pooled means and LLNs (95% confidence intervals) were -20.1% (-20.7%, -19.6%) and -15.4% (-16.0%, -14.7%) respectively for 2D-LVGLS; -21.9% (-23.4%, -20.3%) and -15.3% (-16.9%, -13.8%) respectively for 2D-LVGCS; and 48.4% (43.8%, 53.0%) and 25.5% (17.8%, 33.1%) respectively for 2D-LVGRS. All pooled analyses demonstrated significant heterogeneity, and means and LLNs of and 3D-LV strains differed marginally from 2D. Only vendor software was associated with differences in pooled means and LLN of 2D-LVGLS.

Conclusions

In conclusion, pooled means and LLNs of 2D- and 3D-LV global strain parameters in healthy subjects were reported. Based on the pooled LLNs, thresholds for abnormal, borderline and normal strains can be defined, such as less negative than -14.7%, between -14.7% and -16.0% and more negative than -16.0% respectively for 2D-LVGLS, and 2D-LVGLS values are only affected by vendor software.

His bundle pacing–is it the final frontier of physiological pacing ?–A single centre experience from the Indian sub–Continent

Background

Long term right ventricular pacing can have deleterious effects on left ventricular (LV) function. His bundle pacing (HBP), a novel procedure can probably circumvent this setback. We investigated if (1) HBP is associated with pacing induced LV dysfunction by using LV global longitudinal strain (GLS) and (2) intermediate term performance of the Select Secure (3830) lead in the His bundle location. This report is probably the first on HBP in the Indian population.

Methods

61 patients, with normal LV ejection fraction (EF) with a guideline based indication for permanent pacing underwent a HBP pacemaker implantation using the His Select Secure 3830 lead; with lead guided mapping for locating the His bundle. The patients underwent GLS assessment; evaluation of the His lead parameters - sensing, impedance and capture thresholds immediately after implantation and at 6 months in addition to the standard follow up.

Results

At 6 month follow up, the average GLS did not show significant variation from baseline in patients requiring ventricular pacing more than 40% and was similar, irrespective of selective or non selective His bundle pacing. All the patients had stable pacemaker parameters - with little change in capture threshold, lead impedance or sensing of the His bundle lead - implying electrical and mechanical stability on intermediate term follow-up.

Conclusion

HBP is a feasible procedure in the hands of an experienced operator, with stable lead performance. It does not appear to be associated with pacing mediated left ventricular dysfunction at intermediate term follow up. It should probably become the default method of permanent pacing.

Clinical Influence and Predictors of Pacing-Induced Mechanical Asynchrony in Patients with Normal Cardiac Function with Ventricular Lead Placed in Non-Apical Position

Right ventricular apical (RVA) pacing often causes left ventricular (LV) mechanical asynchrony, which is enhanced by impaired cardiac contraction and intrinsic conduction abnormality. However, data on patients with normal cardiac function and under RV non-apical (non-RVA) pacing are limited.We retrospectively investigated 97 consecutive patients with normal ejection fraction who received pacemaker implantation for atrioventricular block with the ventricular lead placed in a non-RVA position. We defined mechanical asynchrony as discoordinate contraction between opposing regions of the LV wall evaluated by echocardiography. Asynchrony was detected in 9 (9%) patients at baseline and in 38 (39%) under non-RVA pacing (P < 0.001). Asynchrony at baseline was significantly associated with complete left bundle branch block (CLBBB) [odds ratio (OR) = 20.8, P < 0.001]. Asynchrony under non-RVA pacing was significantly associated with left anterior fascicular block (LAFB) (OR = 7.14, P < 0.001) and CLBBB (OR = 13.3, P = 0.002) at baseline. New occurrence of asynchrony was significantly associated with LAFB at baseline (OR = 5.88, P = 0.001). During a median follow-up period of 4.8 years, the incidence of device-detected atrial fibrillation (AF) was more frequent in patients who developed asynchrony than in those who did not (53.3% versus 27.5%, hazard ratio = 2.17, 95% confidence interval = 1.02-4.61, P = 0.03).In patients with normal cardiac function, LAFB at baseline was significantly associated with new occurrence of mechanical asynchrony under non-RVA pacing. Abnormal contraction had a significant influence on the incidence of device-detected AF.

Electrocardiographic predictors of validated right ventricular outflow tract septal pacing for correct localization of transthoracic echocardiography

BACKGROUND

Electrocardiographic (ECG) characteristics of true right ventricular outflow tract (RVOT) septal pacing have not been clearly demonstrated.

HYPOTHESIS

We hypothesized that ECG parameters would help operators differentiate true RVOT septum from non-septal septum.

METHODS

We analyzed 151 patients who underwent pacemaker implantation with a ventricular lead in the RVOT. Transthoracic echocardiographic (TTE) determination of pacing sites was applied in all patients after implantation. A 12-lead ECG was recorded during forced ventricular pacing.

RESULTS

According to TTE orientation, pacing at the RVOT septum was achieved in 94 patients (62.3%). Compared with nonseptal pacing, septal pacing had significantly shorter QRS duration (139.2 ± 18.5 ms vs 155.5 ± 14.7 ms; P < 0.001). More frequent negative or isoelectric QRS vector in lead I (76% vs 32%; P < 0.001), lead II/III R-wave amplitude ratio < 1 (52% vs 25%; P = 0.001), and aVR/aVL QS-wave amplitude ratio < 1 (59% vs 32%; P = 0.001) were observed in septal pacing. Transitional zone (TZ) score (3.8 ± 0.96 vs 4.2 ± 0.90; P = 0.004) and TZ index (0.3 ± 0.5 vs 0.6 ± 0.7; P = 0.008) were significantly lower in septal pacing than in nonseptal pacing, respectively. In multivariate analysis, paced QRS duration and negative or isoelectric QRS vector in lead I independently predicted RVOT septal pacing (P < 0.001). At ROC curve analysis, paced QRS duration ≤145 ms identified RVOT septal pacing with 85.1% sensitivity and 78.9% specificity.

CONCLUSIONS

This study reveals the heterogeneity of lead placement within the RVOT. Narrower paced QRS duration and negative or isoelectric QRS vector in lead I independently predict RVOT septal pacing.

Incremental Value of Two Dimensional Speckle Tracking Echocardiography in the Functional Assessment and Characterization of Subclinical Left Ventricular Dysfunction

Subclinical left ventricular (LV) dysfunction refers to subtle abnormalities in LV function which typically precede a reduction in the left ventricular ejection fraction (LVEF). The assessment of myocardial function using LVEF, a radial metric of systolic function, is subject to load dependence, intra-observer and inter-observer variability. Reductions in LVEF typically manifest late in the disease process thus compromising the ability to intervene before irreversible impairment of systolic performance sets in. 2-Dimensional speckle tracking echocardiography (2D-STE), a novel strain imaging modality has shown promise as a sensitive indicator of myocardial contractility. It arms the clinician with a powerful and practical tool to rapidly quantify cardiac mechanics, circumventing several inherent limitations of conventional echocardiography. This article highlights the incremental utility of 2D-STE in the detection of subclinical LV dysfunction.

Functional characteristics of left ventricular synchronization via right ventricular outflow-tract pacing detected by two-dimensional strain echocardiography

BACKGROUND

Recently, due to the detrimental effects on the ventricular function associated with right ventricular apical (RVA) pacing, right ventricular septal (RVS) pacing has become the preferred pacing method. However, the term RVS pacing refers to both right ventricular outflow-tract (RVOT) and mid-septal (RVMS) pacing, leading to a misinterpretation of the results of clinical studies. The purpose of this study, therefore, was to elucidate the functional differences of RVA, RVOT, and RVMS pacing in patients with atrioventricular block.

METHODS

We compared the QRS duration, global longitudinal strain (GLS), and left ventricular (LV) synchronization parameters at the three pacing sites in 47 patients. The peak systolic strain (PSS) time delay between the earliest and latest segments among the 18 LV segments and standard deviation (SD) of the time to the PSS were also calculated for the 18 LV segments at each pacing site using two-dimensional (2D) strain echocardiography.

RESULTS

RVMS pacing was associated with a significantly shorter QRS duration compared with RVA and RVOT pacing (154.4±21.4 vs 186.5±19.9 and 171.1±21.5 ms, P<0.001). In contrast, RVOT pacing revealed a greater GLS (-14.69±4.92 vs -13.12±4.76 and -13.51±4.81%, P<0.001), shorter PSS time delay between the earliest and latest segments (236.0±87.9 vs 271.3±102.9 and 281.9±126.6%, P=0.007), and shorter SD of the time to the PSS (70.8±23.8 vs 82.7±30.8 and 81.5±33.7 ms, P=0.002) compared with RVA and RVMS pacing.

CONCLUSIONS

These results suggest that the functional characteristics of RVOT pacing may be a more optimal pacing site than RVMS, regardless of the pacing QRS duration, in patients with atrioventricular conduction disorders.

One-Month Global Longitudinal Strain Identifies Patients Who Will Develop Pacing-Induced Left Ventricular Dysfunction over Time: The Pacing and Ventricular Dysfunction (PAVD) Study

Background

Predicting which individuals will have a decline in left ventricular (LV) function after pacemaker implantation remains an important challenge. We investigated whether LV global longitudinal strain (GLS), measured by 2D speckle tracking strain echocardiography, can identify patients at risk of pacing-induced left ventricular dysfunction (PIVD) or pacing-induced cardiomyopathy (PICMP).

Methods

Fifty-five patients with atrioventricular block and preserved LV function underwent dual-chamber pacemaker implantation and were followed with serial transthoracic echocardiography for 12 months for the development of PIVD (defined as a reduction in LV ejection fraction (LVEF) ≥5 percentage points at 12 months) or PICMP (reduction in LVEF to <45%).

Results

At 12 months, 15 (27%) patients developed PIVD; of these, 4 patients developed PICMP. At one month, GLS was significantly lower in the 15 patients who subsequently developed PIVD, compared to those who did not (n = 40) (GLS -12.6 vs. -16.4 respectively; p = 0.022). When patients with PICMP were excluded, one month GLS was significantly reduced compared to baseline whereas LVEF was not. One-month GLS had high predictive accuracy for determining subsequent development of PIVD or PICMP (AUC = 0.80, optimal GLS threshold: <−14.5, sensitivity 82%, specificity 75%); and particularly PICMP (AUC = 0.86, optimal GLS threshold: <−13.5, sensitivity 100%, specificity 71%).

Conclusions

GLS is a novel predictor of decline in LV systolic function following pacemaker implantation, with the potential to identify patients at risk of PIVD before measurable changes in LVEF are apparent. GLS measured one month after implantation has high predictive accuracy for identifying patients who later develop PIVD or PICMP.

Radial left ventricular dyssynchrony by speckle tracking in apical versus non apical right ventricular pacing- evidence of dyssynchrony on medium term follow up

INTRODUCTION

To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony.

METHODS

This was retrospective prospective study. Fifteen patients each with right ventricular (RV) apical (RV apex and apical septum) and non-apical (mid septal and low right ventricular outflow tract [RVOT]) were programmed to obtain 100% ventricular pacing for evaluation by echo. Location and orientation of lead tip was noted and archived by fluoroscopy. Electrocardiography (ECG) was archived and 2D echo radial dyssynchrony was calculated.

RESULTS

The baseline data was similar between two groups. Intraventricular dyssynchrony was significantly more in apical location as compared to non-apical location (radial dyssynchrony: 108.2 ± 50.2 vs. 50.5 ± 24, P < 0.001; septal to posterior wall delay [SLWD] 63.5 ± 27.5 vs. 34 ± 10.7, P < 0.001, SPWD 112.5 ± 58.1 vs. 62.7 ± 12.1, P = 0.003). The left ventricular ejection fraction was decreased more in apical location than non apical location. Interventricular dyssynchrony was more in apical group but was not statistically significant. The QRS duration, QTc and lead thresholds were higher in apical group but not statistically significant.

CONCLUSION

Pacing in non apical location (RV mid septum or low RVOT) is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term.

Changes in Left Ventricular Global and Regional Longitudinal Strain During Right Ventricular Pacing

Background

Our study aimed to demonstrate the short-term impacts of right ventricular apical pacing (RVAP) and right ventricular septal pacing (RVSP) on left ventricular (LV) regional longitudinal strain (RLS) and global longitudinal strain (GLS) in patients with preserved ejection fraction (EF). LV strain and functions may be altered by RVAP. RVSP might be a better alternative. The detrimental effect of right ventricular (RV) pacing may be mediated by regional LV impairment.

Methods

Sixty-two patients indicated for permanent pacemaker implantation and preserved LV systolic function were included. Dual chamber pacemakers were implanted in all patients. Patients were divided into two groups according to RV lead position: group A (RVAP, n = 32) and group B (RVSP, n = 30). Patients were examined at baseline and after 6 months of implantation for LV systolic functions, global and regional strain by echocardiography and 2D speckle tracking echocardiography.

Results

Paced QRS duration was significantly shorter in group B compared to group A patients (P = 0.02). Regarding ventricular strain, there was no statistically significant difference between both groups at baseline measurements in comparisons of GLS, relative apical longitudinal strain (rALS) and RLS (P > 0.05). In contrast, there was statistically significant difference between both groups in results of GLS (P = 0.01) at 6 months. In addition, RLSs in septal, apical and rALS were affected after 6 months with P values of 0.02, 0.03 and 0.03, respectively.

Conclusion

RVAP appears to worsen GLS more than RVSP, and the resultant decrease in apical strain is most correlated region to decrease in GLS.

Effects of right ventricular pacing sites on blood pressure variation in upright posture: a comparison of septal vs. apical pacing sites

AIMS

Large variations in blood pressure (BP) in the upright position are a major cause of pacemaker syndrome, observed in up to 80% of patients paced non-physiologically at the right ventricular (RV) apex. We hypothesized that the magnitude of BP variations might be influenced by the RV pacing site. To assess this, we compared haemodynamic findings during supine and upright posture with RV apical vs. septal pacing.

METHODS AND RESULTS

The study population comprised a retrospective cohort of 24 dual-chamber pacemaker patients with advanced or complete atrioventricular block, in which 11 were randomly chosen from those with RV apical pacing, and 13 randomly chosen from those with septal pacing. Studies were performed during fixed rate VVI and DDD pacing modes with patients in both supine and passive head-up tilt positions. Continuous BP, stroke volume, cardiac index, and total peripheral resistance index were measured non-invasively. During RV apical pacing, there were significant differences of beat-to-beat BP variation after movement from supine to upright posture for both VVI and DDD pacing modes (P < 0.05); however, this was not the case for either mode during RV septal pacing. Further, comparing RV apical to RV septal pacing in the supine position, there were no BP variation differences for either DDD or VVI modes. Conversely, in the upright position BP variation was significantly greater during RV apical vs. RV septal VVI pacing (P = 0.017) but not during DDD pacing.

CONCLUSION

During VVI pacing, RV septal pacing exhibited lesser BP variation during upright posture compared with RV apical pacing.

A randomized comparison of fluoroscopic techniques for implanting pacemaker lead on the right ventricular outflow tract septum

Right ventricular outflow tract (RVOT) septal pacing is commonly performed under the standard fluoroscopic positions during procedure. The aim of the prospective, randomized study was to evaluate the accuracy of the combination of standard fluoroscopic and left lateral (LL) fluoroscopic views for determination of RVOT septal position compared with standard fluoroscopic views alone. We prospectively enrolled patients who had indications for implantation of a permanent pacemaker. Patients were randomly assigned into two groups based on intraoperative fluoroscopic views as follows: LL group (three standard fluoroscopic views + LL fluoroscopic view) or standard group (three standard fluoroscopic views). Transthoracic echocardiography (TTE) determination of pacing sites was applied in all patients 3 days after pacemaker implantation. The implantation success rate of RVOT septal pacing was compared between groups. A total of 143 patients (59 males, mean age 57.6 ± 16.3 years) with symptomatic bradyarrhythmia were studied, of whom, 72 patients were randomized to LL group and 71 to standard group. TTE determination of pacing sites was compared with two groups. In the LL group, 60 patients (83 %) were achieved in RVOT septal position. In the standard group, however, the position of RVOT septum was only observed in 48 patients (68 %). The success rate of RVOT septal position in LL group was significantly higher than standard group (p = 0.029). Comparing to traditional views, combining LL view in the procedure will approve the accuracy of RVOT septal pacing site.

Randomized placebo controlled blinded study to assess valsartan efficacy in preventing left ventricle remodeling in patients with dual chamber pacemaker--Rationale and design of the trial

BACKGROUND

Dual chamber pacing is known to have detrimental effect on cardiac performance and heart failure occurring eventually is associated with increased mortality. Experimental studies of pacing in dogs have shown contractile dyssynchrony leading to diffuse alterations in extracellular matrix. In parallel, studies on experimental ischemia/reperfusion injury have shown efficacy of valsartan to inhibit activity of matrix metalloproteinase-9, to increase the activity of tissue inhibitor of matrix metalloproteinase-3 and preserve global contractility and left ventricle ejection fraction.

PURPOSE

To present rationale and design of randomized blinded trial aimed to assess whether 12 month long administration of valsartan will prevent left ventricle remodeling in patients with preserved left ventricle ejection fraction (LVEF ≥ 40%) and first implantation of dual chamber pacemaker.

METHODS

A total of 100 eligible patients will be randomized into three parallel arms: placebo, valsartan 80 mg/daily and valsartan 160 mg/daily added to previously used drugs. The primary endpoint will be assessment of valsartan efficacy to prevent left ventricle remodeling during 12 month follow-up. We assess patients' functional capacity, blood plasma activity of matrix metalloproteinases and their tissue inhibitors, NT-proBNP, tumor necrosis factor alpha, and Troponin T. Left ventricle function and remodeling is assessed echocardiographically: M-mode, B-mode, tissue Doppler imaging.

CONCLUSION

If valsartan proves effective, it will be an attractive measure to improve long term prognosis in aging population and increasing number of pacemaker recipients. ClinicalTrials.org (NCT01805804).

The acute and chronic effects of different right ventricular site pacing on left ventricular mechanical synchrony as assessed by phase analysis of SPECT myocardial perfusion imaging

BACKGROUND

This study aimed to assess acute and chronic effects of right ventricular mid-septum (RVS) versus right ventricular apex (RVA) pacing on left ventricular (LV) mechanical dyssynchrony using phase analysis of gated single photon emission computed tomography myocardial perfusion imaging (MPI).

METHODS

Thirty-nine patients with complete atrioventricular (AV) block, who were indicated for permanent pacing, were recruited and randomized to receive RVA (n = 20) or RVS (n = 19) pacing. All patients underwent MPI at 1 week and 6 months after pacemaker implantation. LV dyssynchrony and cardiac function were assessed by MPI and compared between the two groups.

RESULTS

There were no significant differences in baseline characteristics between the RVS and RVA groups. The paced QRS duration was significantly longer in the RVA group than in the RVS group. LV dyssynchrony parameters were not significantly different between the groups at the 1-week follow-up, but they were significantly smaller in the RVS group than in the RVA group at the 6-month follow-up. LV dyssynchrony parameters significantly decreased in the RVS group from the 1-week follow-up to the 6-month follow-up, but were unchanged in the RVA group. No differences in LV function parameters were observed between the groups at the 1-week and 6-month follow-ups.

CONCLUSIONS

RVS pacing produces better electrical and mechanical synchrony than RVA pacing for patients with complete AV block.

[Right ventricular septal stimulation would produce similar bi-ventricular dyssynchrony as does apical stimulation in patients with normal ejection fraction]

OBJECTIVE

To determine in patients with normal ejection fraction, undergoing permanent VVI pacing, if medial septal stimulation has lower dyssynchrony than apical stimulation assessed by echocardiography.

METHOD

A prospective trial, 19 patients>70 years old, scheduled for VVI pacemaker implantation for complete degenerative atrioventricular block, ventricular frequency<50beat per minute and ejection fraction≥45%. Patients with atrial fibrillation, heart failure, left bundle branch block and QRS durations longer than 120milliseconds in surface electrocardiogram with sinus rhythm were excluded. Patients were randomized to apical implantation group A: 47% and septal implantation group B: 53%. Echocardiographic parameters were measured previous to the implant, 48h, 5 and 48 months after implantation.

RESULTS

No patients had diagnosis of ischemic cardiomyopathy or heart failure. Echocardiographic parameters for interventricular dyssynchrony between groups were A: 14.44±19.76msec vs. B: 9±36.45msec; A: 6.11±62.11msec vs. B: 13±38.31msec; A: 77±53.51msec vs. B: 24.29±80.90msec, P=NS). For interventricular dyssynchrony were A: 46.44±19.76msec vs. B: 42.20±29.56msec; A: 45.33±45.67msec vs. B: 29.80±44.66msec; A: 46,38±20 msec vs. B: 21±27.20msec, P=NS) at 48h, 5 and 48 months, respectively.

CONCLUSION

Apical site of stimulation does not increase ventricular dyssynchrony rate in patients with preserved ejection fraction. Septal stimulation showed decreased trend in interventricular dyssynchrony.

Medium-term effects of septal and apical pacing in pacemaker-dependent patients: a double-blind prospective randomized study

BACKGROUND

Pacing the right ventricle is established practice, but there remains controversy as to the optimal site to preserve hemodynamic function.

AIMS

To evaluate clinical and hemodynamic differences between apical and septal pacing in pacemaker-dependent patients.

METHODS

Patients receiving their first pacemaker for advanced atrioventricular block, with the atria in sinus rhythm, were randomized to receive apical (Group A) or septal (Group S) ventricular leads. After implant, with the device programmed VVI 70 beats/min fixed rate, patients underwent a 6-minute walk test and a transthoracic echocardiogram. Then, DDDR was programmed at nominal settings. The same tests were performed at 6 months and 12 months follow-up. If ventricular pacing was less than 98%, the patient was excluded.

RESULTS

A total of 142 patients were included in the study. During the study year, 71 (50%) were excluded for not fulfilling the condition of 98% ventricular pacing. Groups A and S had 34 and 37 patients, respectively. Age and gender were similar in the groups. At implant, QRS duration was significantly greater in Group A (158 ms) than Group S (146 ms; P = 0.018), and the QRS axis was different: -74.5° in Group A and 1° in Group S (P < 0.001). At 1 year, the 6-minute walk improved significantly in both groups: Group A 15% (P = 0.048) and Group S 24% (P = 0.001). Left ventricular ejection fraction (LVEF) increased from 0.57 to 0.61 (P = 0.008) in Group S, without significant change in Group A.

CONCLUSIONS

After 1 year, pacemaker-dependent patients with septal ventricular leads have better clinical and functional (LVEF) outcome.

Selective site pacing from the right ventricular mid-septum. Follow-up of lead performance and procedure technique

Pacing from the right ventricular (RV) apex is associated with adverse effects such as heart failure and atrial fibrillation. We attempted pacing from the RV mid-septum, which is theoretically a more physiological pacing site. A total of 172 consecutive patients with indications for permanent pacemaker implantation were studied. A screw-in lead and a curved stylet were used for lead positioning on the RV mid-septum. Pacemaker indices were evaluated at implantation and one year later. As an electrocardiographic parameter, QRS duration was measured in lead II. These data were compared to those of 66 patients subjected to conventional RV apical pacing. Lead placement was successful in all patients of RV mid-septal pacing. There were no technical problems during or after the procedure. The cumulative percentage of ventricular pacing at one year postimplantation was 85 ± 24 % in the SSP group. Sensing, pacing threshold, and lead impedance in the SSP group remained clinically stable over one year. When these measurements were compared between the SSP and AP groups, the pacing threshold and the lead impedance at one year postimplantation in the SSP group were higher (P < 0.05) and lower (P < 0.01), respectively, than those of the AP group. The mean QRS duration was markedly shorter (123 ± 16 versus 150 ± 18 msec, P < 0.0001). Selective site pacing from the RV mid-septum is feasible and results in less conduction delay compared to conventional RV apical pacing, and its procedure seems to be more physiological in permanent pacemaker implantation.