Long-term Right Ventricular Apical Pacing Research Articles

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

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. We aimed to identify the short-term effects of the pacemaker RV lead position on remodeling of LV systolic functions. The study included 30patients who presented with an indication of permanent pacing and who underwent permanent single- or dual-chamber pacemaker insertion: 15patients with RV apical pacing (RV apex), and 15patients 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 a3-month follow-up. At the 3‑month follow-up, post-pacing 2Dspeckle 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). In the short-term follow-up, 2Dspeckle tracking echocardiography showed more radial dyssynchrony in the apical location than in the non-apical location of RV lead. The RV septal pacing is abetter 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.

Preliminary study on left bundle branch area pacing in children: Clinical observation of 12 cases.

Left bundle branch area pacing (LBBAP) maintains electrical and mechanical synchronization of the ventricles. It is a relatively physiological pacing mode, with low and stable pacing threshold and wider indications. LBBAP in children has been rarely reported. This study observed 12 children attempted LBBAP from January 2019 to January 2021 in the department of pediatric cardiology of Anzhen Hospital prospectively. Clinical data, pacing parameters, electrocardiograms, intracardiac electrograms, echocardiographic measurements and complications were recorded at implant and during follow-up. The 12 patients aged between 3 and 14 years old and weighted from 13 to 48 kg. Eleven patients were diagnosed with third-degree atrioventricular block and 1 patient (case 4) suffered from cardiac dysfunction due to right ventricular apical pacing (RVAP). Left bundle branch area pacing was successfully achieved in all patients with narrow QRS complexes and V1 lead showed changes like right bundle branch block in the pacing electrocardiogram. Left ventricular ejection fraction in case 4 recovered on the 3rd day after LBBAP. The median of left ventricular end diastolic diameter Z score of the 12 patients decreased from 1.75 to 1.05 3 months after implantation (p < 0.05). The median of paced QRS duration was 103 ms. The median of pacing threshold, R-wave amplitude and impedance were 0.85 V, 15 mV and 717 Ω respectively and remained stable during follow-up. No complications such as loss of capture, lead dislodgement or septal perforation occurred. Left bundle branch area pacing can be performed safely in children with narrow QRS duration and stable pacing parameters. Cardiac dysfunction caused by long-term RVAP can be corrected by LBBAP quickly.

Permanent His bundle pacing: shaping the future of physiological ventricular pacing.

Conventional right ventricular (RV) pacing, particularly RV apical pacing, can have deleterious effects on cardiac function. Long-term RV apical pacing has been associated with increased risk of atrial fibrillation, hospitalization for heart failure, pacing-induced cardiomyopathy and associated death. His bundle pacing (HBP) results in physiological ventricular activation and has generated tremendous research interest and enthusiasm. By stimulating the His-Purkinje network directly, HBP results in synchronized ventricular activation, which might translate into improved clinical outcomes compared with dyssynchronous ventricular activation with RV apical pacing. HBP can also overcome bundle branch block patterns, and data are accumulating on the benefit of HBP for cardiac resynchronization therapy. In this Review, we summarize the anatomy of the His bundle and early clinical observations, implantation techniques and available outcome data associated with permanent HBP. We also highlight the challenges with HBP and the need for additional tools and more randomized data before widespread application of permanent HBP.

Right Ventricular Septal Pacing: A Paradigm Shift.

The right ventricular (RV) apex has been considered to be the primary site for ventricular lead implantation since the original descriptions of permanent pacing. However, long-term RV apical pacing has been shown to have negative effects on ventricular function and hemodynamics as a result of ventricular dyssynchrony. Alternative sites of ventricular pacing, particularly the RV septum and His bundle, have been evaluated for patients with a need for long-term ventricular pacing. In this article, we review the available data on the use of these alternative sites for RV pacing.

Impact of simple electrocardiographic markers as predictors for deterioration of left ventricular function in patients with frequent right ventricular apical pacing.

Several trials demonstrated that frequent right ventricular apical pacing (RVAP) was associated with cardiac dysfunction and an increased rate of heart failure hospitalization. However, there are few reports about the 12-lead electrocardiogram (12-ECG) parameters at the time of device implantation to predict deterioration of LVEF in patients with frequent RVAP. We retrospectively studied 115 consecutive patients undergoing pacemaker or implantable cardioverter-defibrillator implantation with RVAP, with rate of ventricular pacing≥40% and LVEF≥50% at the time of implantation. We compared the 12-ECG characteristics at the time of device implantation between patients with deterioration of LVEF (≥10% reduction) and those without. Twenty-nine patients (25%) had deteriorated LVEF with a decrease in mean LVEF from 59 to 40% during a median follow-up period of 8.9 [4.6-13.7] years. Multivariate logistic regression analysis showed that cumulative % of ventricular pacing [odds ratio (OR) 1.04 per 1% increase, 95% confidence interval (CI) 1.01-1.09, p=0.04], notching of baseline paced QRS in limb leads (OR 5.04, 95% CI 1.59-19.6, p=0.005) and the QS pattern in all precordial leads (OR 3.56, 95% CI 1.21-10.8, p=0.02) were independently associated with deterioration of LVEF. The QS pattern of baseline paced QRS in all precordial leads had 58% sensitivity, 93% specificity for the RV lead position at the tip of RV apex. In conclusion, considering OR by multivariate analysis, notching of baseline paced QRS in limb leads and the QS pattern in all precordial leads at device implantation may be simple and useful predictors to identify patients who are at risk for deterioration of cardiac function during long-term RVAP. 12-ECG monitoring at device implantation and avoidance of the RVAP site showing a QS pattern may be important to prevent deterioration of cardiac function in patients with frequent RVAP.

Relation of Right Ventricular Pacing Site to Left Ventricular Mechanical Synchrony

Transvenous pacing leads are regularly placed in the right ventricular (RV) apex. Pediatric patients can develop myopathic changes after long-term RV apical pacing. Left ventricular (LV) mechanical dyssynchrony, estimated with echocardiography, may explain the acute decrease in LV function and long-term histopathologic changes. Ts-4w is an established echocardiographic measurement of LV synchrony, using tissue Doppler imaging (TDI). The purpose of this study was to determine whether TDI could identify acute changes in LV synchrony during pacing from different RV sites. We prospectively measured Ts-4w and Doppler-derived cardiac output after 5 minutes of pacing in 19 subjects undergoing catheter ablation. Each subject underwent pacing at 4 sites in random order: high right atrium, high RV septum (septal), RV outflow tract, and RV apex. Ts-4w was measured during sinus rhythm and each pacing protocol, with a value >65 ms defining mechanical dyssynchrony. Ts-4w during high right atrial (32.6 +/- 17.6 ms) and septal (28.9 +/- 10.9 ms) pacing were not different from sinus rhythm (39.5 +/- 15.5 ms). RV apex (85.7 +/- 18.4 ms) and RV outflow tract (84.2 +/- 20.4 ms) pacing induced mechanical dyssynchrony (p <0.0001). In conclusion, TDI demonstrated significant differences in LV synchrony related to pacing site. Ts-4w may be useful to determine ideal lead placement because it correlates with acutely improved hemodynamics.

The Road to Right Ventricular Septal Pacing: Techniques and Tools

Prolonged right ventricular (RV) apical pacing is associated with progressive left ventricular dysfunction due to dysynchronous ventricular activation and contraction. RV septal pacing allows a narrower QRS compared to RV apical pacing, which might reflect a more physiological and synchronous ventricular activation. Previous clinical studies, which did not consistently achieve RV septal pacing, were not confirmatory and need to be repeated. This review summarizes the anatomy of the RV septum, the radiographic appearances of pacing leads in the RV, the electrocardiograph correlates of RV septal lead positioning, and the techniques and tools required for implantation of an active-fixation lead onto the RV septum. Using the described techniques and tools, conventional active-fixation leads can now be reliably secured to either the RV outflow tract septum or mid-RV septum with very low complication rates and good long-term performance. Even though physiologic and hemodynamic studies on true RV septal pacing have not been completed, the detrimental effects of long-term RV apical pacing are significant enough to suggest that it is now time to leave the RV apex and secure all RV leads onto the septum.

Is the left ventricle the preferred pacing site in all children with atrioventricular block?

This editorial refers to ‘Preserved cardiac synchrony and function with single-site left ventricular epicardial pacing during mid-term follow-up in paediatric patients’ by M. Tomaske et al., on page 1168 Cardiac pacing for the treatment of bradycardia has been applied in children of all age groups for many years. In the paediatric population, the most common indications for cardiac pacing are auto-immune-mediated congenital atrioventricular block (CAVB) and acquired CAVB after congenital heart surgery. Traditionally, the right ventricular (RV) apex has been used for transvenous ventricular pacing leads because it is easily accessible and allows a stable position and low pacing thresholds. In young children, many centres prefer to place epicardial ventricular pacing leads, which are usually attached to either the RV apex or the RV free wall. Although thousands of children have profited from pacing the RV, there is increasing evidence that long-term RV apical pacing (RVP) eventually can result in LV failure. In animal studies, it has been demonstrated that chronic RVP leads to decreased LV function, dilatation, and asymmetric septal hypertrophy. 1 Clinical studies in adults have demonstrated that RVP is associated with increased mortality and morbidity related to heart failure. 2 Reports in children have also shown that long-term RVP causes LV mechanical dyssynchrony, which is associated with decreased LV function. 3,4 The deleterious effect of permanent RV pacing has become an important topic in cardiac pacing in the paediatric population, since this group requires pacemaker therapy over many decades. This young pacemaker population also includes a significant number of children with complex congenital heart disease at high risk for future heart failure. Literature data indicate that in children with normal cardiac anatomy, long-term RVP will lead to LV failure in 7%. 4 A very recent study by Gebauer et al. 5 reported even higher percentage (13%) of LV dilatation in a retrospective cohort of 82 patients after a mean pacing period of 7.4 years. In this study, children with epicardial RV free wall pacing had a higher risk of LV dilatation and LV dysfunction compared with those with RVP. 5 Furthermore, small case series has demonstrated that children with congenital CAVB who developed RV pacing-associated cardiomyopathy showed impressive improvement of LV function after cardiac resynchronization therapy (CRT). These findings indicate that mechanical dyssynchrony induced by RV pacing appeared to be the key factor in the development of heart failure in this group of congenital CAVB. Also, the CRT data in children and patients with congenital heart disease from three large studies have shown that 45‐70% of children undergoing CRT for heart failure had pacing-induced ventricular dyssynchrony. 6 So, if the RV apex appears inappropriate for long-term ventricular pacing, what then should we use as an alternative? In the RV, selective pacing sites at the high RV septum and RV outflow tract region may produce more synchronous contraction patterns and better haemodynamics. Therefore, RV septal pacing could decrease the long-term detrimental effects of RV pacing. Advanced tools and lead technology nowadays allow for pacing these specific RV sites, also in paediatric patients. However, to date, long-term clinical studies have been conflicting, and large randomized trials are now expected to demonstrate the significance of selective site RV pacing in the protection of LV function. 7 LV pacing appears to be less harmful than RVP as shown in acute haemodynamic studies in patients with normal LV function. 8 Animal studies as well as an acute haemodynamic study in children have suggested that the LV apex is the optimal pacing site in the LV. 9 Trials in adult patients have shown that single-site LV free wall pacing (LVP), comparable with biventricular pacing, has beneficial haemodynamic effects in patients with heart failure and left bundle branch block. 10 Also, a small study in children with LV dysfunction and RVP or intrinsic left bundle branch block has demonstrated improvement of LV function 1 month after single-site LVP. 11

New‐Onset Heart Failure After Permanent Right Ventricular Apical Pacing in Patients with Acquired High‐Grade Atrioventricular Block and Normal Left Ventricular Function

Emerging data have suggested that right ventricular (RV) apical pacing results in progressive left ventricular (LV) dysfunction and contributes to the development of heart failure (HF). This study aimed to investigate the prevalence and clinical predictors for the development of new-onset HF after long-term RV apical pacing in patients with acquired atrioventricular (AV) block who require permanent pacing. We studied the clinical outcomes after long-term RV apical pacing for acquired AV block in 304 patients without a prior history of HF. All patients had >90% ventricular pacing as determined by device diagnostic data. After a median follow-up of 7.8 years, 79 patients (26.0%) developed new-onset HF after RV apical pacing. Univariate Cox-regression analysis revealed that older age at the time of pacemaker implantation (P < 0.001), the presence of coronary artery disease (CAD) (P < 0.001) or atrial fibrillation (P = 0.03), VVI pacemaker (P < 0.001), wider paced QRS duration (P < 0.001), and new-onset myocardial infarction (P < 0.001) were predictors for HF. Multivariate analysis revealed that older age at implantation (Hazard ratio [HR] 1.06, 95% confidential interval [CI] 1.04-1.09, P < 0.001), CAD (HR 1.98, 95% CI 1.12-3.50, P < 0.05), and a wider paced QRS duration (HR 1.27 for each 10 ms increment, 95% CI 1.11-1.45, P = 0.001) were independent predictors of HF. Furthermore, cardiovascular mortality was significantly increased in those with HF (36.7% vs. 2.7%, P < 0.001). After a median follow-up of 7.8 years, permanent RV apical pacing was associated with HF in 26% of patients. Elderly age at the time of implant, a wider paced QRS duration and the presence of CAD independently predicted new-onset HF. More importantly, HF after RV apical pacing was associated with a higher cardiovascular mortality.

Left ventricular dysfunction after long-term right ventricular apical pacing in the young

OBJECTIVESThe goal of this study was to assess long-term global left ventricular (LV) function in patients paced from the right ventricular (RV) apex at a young age.BACKGROUNDVentricular contraction asynchrony with short-term RV apical pacing has been associated with reduced LV pump function and relaxation. The long-term effect of RV apical pacing on global LV function in the young remains unknown.METHODSTwenty-four patients with normal segmental anatomy paced from the RV apex (follow-up 1 to 19 years) underwent noninvasive assessment of global LV function with automated border detection echocardiography-derived fractional area of change (FAC), coupled with the Doppler index of myocardial performance (MPI). Data were analyzed from 24 RV-paced patients (mean follow-up 9.5 years, age 19 years, body surface area [BSA] 1.6 m2, QRS duration 140 ms) and compared with 33 age- and BSA-matched control subjects (age 16.4 years, BSA 1.6 m2). Multiple linear regression analysis was performed to identify patient variables that can affect these indexes of LV function.RESULTSAssessment of LV function (median follow-up 10 years) in 24 paced patients demonstrated impaired area- and Doppler flow-derived indexes of LV systolic and diastolic function, compared with those indexes of control subjects (FAC: 52% vs. 60%, p < 0.01; MPI: 0.46 vs. 0.34, p < 0.01). Paced QRS interval and age were found to significantly influence global LV contraction in these patients (R2= 0.4, p < 0.05).CONCLUSIONSIn the presence of impaired LV function with long-term RV apical pacing, alternative sites of ventricular pacing that simulate normal biventricular electrical activation should be explored to preserve function in pediatric patients in need of long-term pacing.