Survival Analysis in Patients With Preserved Left Ventricular Function and Standard Indications for Permanent Cardiac Pacing Randomized to Right Ventricular Apical or Septal Outflow Tract Pacing

Abstract

he traditional site for ventricular lead placement-the right ventricular apex (RVA), produces an abnormal pattern of ventricular depolarization, and there is growing evidence that pacing from this site is associated with detrimental functional and structural changes in the heart which might lead to an adverse clinical outcome. [1][2][3] These observations have increased interest in pacing at sites alternative to the RVA, mainly in the area of the right ventricular outflow tract (RVOT). It has been hypothesized that pacing in the RVOT, owing to its proximity to the His-bundle, results in a more physiological depolarization pattern and better hemodynamics and might reduce detrimental effects of long-term ventricular pacing. Results of a meta-analysis comparing RVA to RVOT pacing have suggested acute benefit from pacing at the RVOT. 4 However, poor definition of the outflow tract area and the non-randomized character of most trials confound the data. Longterm evaluation of the effects of chronic pacing are limited, although some mid-term observations show equivalency between apical and outflow tract pacing. 5,6 Other studies indicate that, in contrast to RVA, RVOT pacing preserves left ventricular (LV) function. 7 However, it is still not clear whether RVOT pacing provides better long-term outcome than RVA pacing.In this study we investigated RVOT pacing in comparison to RVA pacing in patients with standard indications for permanent ventricular pacing and preserved LV systolic function to determine whether RVOT pacing would provide better all-cause and cardiovascular survival. MethodsThe present study was a single-center randomized study performed in a tertiary care university hospital. The first patient was enrolled on 7 th September 1995 and the last patient on 24 th November 1997. After the 10-year follow-up visit the long-term survival in the studied population was evaluated. PatientsPatients were eligible for the study if they were at least 21 years old, had preserved LV ejection fraction (LVEF) There were no differences in the all-cause or cardiovascular mortality between the pacing sites after adjustment for age, gender, arterial hypertension, atrial fibrillation, New York Heart Association class and left ventricular end-diastolic diameter. Conclusions:The RVOT provides no additional benefit in terms of long-term survival over RVA pacing. (Circ J

Permanent Cardiac Pacing in Adults with High Grade Atriovetricular Block and Preserved Left Ventricular Function: Optimal Mode and Site of Pacing

“…They concluded that these detrimental effects associated with RVS pacing might have resulted from the heterogeneity of the real pacing sites included under the umbrella of RVS pacing concept. These results are in accordance with other studies (Bourke et al, 2002;Dabrowska-Kugacka et al, 2009). Victor et al (Victor et al, 2006) found that in contrast to RVA pacing, RVS pacing preserved LVEF in patients with baseline LVEF ≤45%, but did not gain any advantage of LVEF in patients with baseline LVEF>45%.…”

“…The RV septal pacing also resulted in shorter isovolumic relaxation than RV apical pacing (Yu et al, 2007), implicating better diastolic function that has been invasively demonstrated by Kolettis et al (Kolettis et al, 2000) at the cardiac catheterization laboratory. In fact despite the beneficial features of reducing electrical and mechanical dyssynchrony , different studies failed to demonstrate a positive effect on indices of LV structure and 85 function and did not confirm the above mentioned clinical outcomes, at least during the 3-18 months after implantation (Bourke et al, 2002;Victor et al, 2006;Kypta et al, 2008;Dabrowska-Kugacka et al, 2009;Gong et al, 2009;Cano et al, 2010) Kypta et al (Kypta et al, 2008) randomized 98 patients with atrioventricular block (AVblock) undergoing pacemaker implantation to positioning the ventricular lead in the high or mid septum (n =53) or in the apex (n = 45) of the right ventricle. The Changes of N-terminal pro-brain natriuetic peptide (BNP) levels, LVEF, and exercise capacity from baseline to 18 months were statistically not different between septal and apical stimulation.…”

“…Right Ventricular Apical permanent pacing could have negative hemodynamic effects. Initially, attention was directed to RV outflow tract/septum pacing and His/para-Hisian pacing in patients with LV dysfunction ( Mera et al, 1999;Schwaab et al, 1999;Buckingham et al, 1997;Buckingham et al, 1998;de Cock et al, 1998) and latter in preserved LV function patients (Giudici et al, 1997;Karpawich & Mital, 1997;Kolettis et al, 2000;Bourke et al, 2002;Tse et al, 2002;Occhetta et al, 2006;Victor et al, 2006;Yu et al, 2007;Kypta et al, 2008;Flevari et al, 2009;Ng et al, 2009;Dabrowska-Kugacka et al, 2009;Takemoto et al, 2009;Gong et al, 2009;Rosso et al, 2010;Verma et al , 2010;106:806-9;Leong et al, 2010;Cano et al,. 2010;Yoshikawa et al, 2010) while subsequently biventricular stimulation began to emerge as an appealing alternative proposal (Yu et al, 2009;Simantirakis et al, 2009;Doshi et al, 2005).…”

“…A pacing site that is in closer proximity with the proximal portion of His bundle at the RV septum should lead to a narrower QRS which in turn might reflect a lesser degree of activation delay compared with RVA pacing (Mera et al, 199;Schwaab et al, 1999;Tse et al, 2002) and less dyssynchrony, as demonstrated by multiple echocardiographic techniques (Tse et, 2002;Flevari et al, 2009;Takemoto et al, 2009;Gong et al, 2009;Leong et al, 2010;Cano et al, 2010). Pacing on the right ventricular (RV) septum, at high (septal RVOT pacing) (Giudici et al, 1997;Kolettis et al, 2000;Bourke et al, 2002;Tse et al, 2002;Dabrowska-Kugacka et al, 2009;Gong et al, 2009;Leong et al, 2010;Yoshikawa et al, 2010), mid (Yu et al, 2007;Cano et al, 2010;Muto et al, 2007) or lower (Flevari et al, 2009) septal pacing position has been introduced as a potentially favorable alternative to RVA pacing to preserve a more physiologic ventricular activation. Previous investigations of alternative pacing sites have yielded inconsistent results (Mera et al, 1999;Giudici et al, 1997;Bourke et al, 2002;Victor et al, 2006;Kypta et al, 2008;Dabrowska-Kugacka et al, 2009;Tse et al Europace 2009;Victor et al, 1999) which may be attributable, in part, to the fact that the pacing site was determined on a topological rather than functional basis (Giudici & Karpawich, 1999).…”

“…Pacing on the right ventricular (RV) septum, at high (septal RVOT pacing) (Giudici et al, 1997;Kolettis et al, 2000;Bourke et al, 2002;Tse et al, 2002;Dabrowska-Kugacka et al, 2009;Gong et al, 2009;Leong et al, 2010;Yoshikawa et al, 2010), mid (Yu et al, 2007;Cano et al, 2010;Muto et al, 2007) or lower (Flevari et al, 2009) septal pacing position has been introduced as a potentially favorable alternative to RVA pacing to preserve a more physiologic ventricular activation. Previous investigations of alternative pacing sites have yielded inconsistent results (Mera et al, 1999;Giudici et al, 1997;Bourke et al, 2002;Victor et al, 2006;Kypta et al, 2008;Dabrowska-Kugacka et al, 2009;Tse et al Europace 2009;Victor et al, 1999) which may be attributable, in part, to the fact that the pacing site was determined on a topological rather than functional basis (Giudici & Karpawich, 1999). Many previous studies (Schwaab et al, 1999;Victor et al, 2006;Yu et al, 2007;Ng et al, 2009;Takemoto et al, 2009;Tse et al, Europace 2009, Gong et al, 2009Leong et al, 2010;Schwaab et al, 2001), have showed that septal pacing induced shorter paced QRS duration than RVA pacing did.…”