Adverse Consequences of Right Ventricular Apical Pacing and Novel Strategies to Optimize Left Ventricular Systolic and Diastolic Function

Abstract

Several studies have focused on the deleterious consequences of Right Ventricular Apical (RVA) pacing on Left Ventricular (LV) function, mediated by pacing-induced ventricular dyssynchrony. Therapeutic strategies to reduce the detrimental consequences of RVA pacing have been proposed, that includes upgrading of RVA pacing to Cardiac Resynchronization Therapy (CRT), alternative Right Ventricular (RV) pacing sites, minimal ventricular pacing strategies, as well as atrial-based pacing. In developing countries, single chamber RV pacing still constitutes a majority of cases of permanent pacing, and assessment of the optimal RV pacing site is of paramount importance. In chronically-paced patients, it is crucial to maintain as close and normal LV physiological function as possible, by minimizing ventricular dyssynchrony, reducing the chances for heart failure and other complications to develop. This review provides an analysis of the deleterious immediate and long-term consequences of RVA pacing, and the most recent available evidence regarding improvements in pacing options and strategies to optimize LV diastolic and systolic function. Furthermore, the place of advanced echocardiography in the identification of patients with pacing-induced LV dysfunction, the potential role of a new predictor of LV dysfunction in RV-paced subjects, and the long- term outcomes of patients with RV septal pacing will be explored.

Pacemaker-induced cardiomyopathy

“…3,10,11 The prevalence of PICM has been shown to be about 9% at 1 year after pacemaker implantation, but can occur within 6 months postoperatively. 3,10,12,13 Other studies have revealed that the risk of developing PICM is more prevalent in men and in patients who have a lower baseline LV ejection fraction, a history of AF, and a native QRS interval wider than 115 ms. 10 PATHOGENESIS PICM is caused by electrical and mechanical abnormalities secondary to the high demand of RV apical pacing. 10,12 During normal conduction, electrical impulses from the sinus node activate the right and left atria.…”

“…3,10 In addition, the LV septum contracts before the lateral wall: This phenomenon, called intraventricular dyssynchrony, manifests as a left bundle-branch block (LBBB) (Figure 1). 3,10,14 Ventricular dyssynchrony reduces the functional capacity of the heart, resulting in cardiomyopathy and heart failure.…”

“…3,10 RV apical pacing also has been implicated in the deterioration of valvular function. 3 Mitral regurgitation may worsen because LV dyssynchrony reduces mitral annular contraction. 11 Research also has revealed that RV apical pacing may induce new-onset tricuspid regurgitation and exacerbate existing tricuspid regurgitation in 25% to 50% of patients.…”

“…3 However, years of research and studies have revealed that RV apical pacing has deleterious effects on LV function and is associated with heart failure and increased rates of hospitalization, morbidity, and mortality. 3,10,11 The prevalence of PICM has been shown to be about 9% at 1 year after pacemaker implantation, but can occur within 6 months postoperatively. 3,10,12,13 Other studies have revealed that the risk of developing PICM is more prevalent in men and in patients who have a lower baseline LV ejection fraction, a history of AF, and a native QRS interval wider than 115 ms. 10 PATHOGENESIS PICM is caused by electrical and mechanical abnormalities secondary to the high demand of RV apical pacing.…”

“…5 Chronic right ventricular (RV) apical pacing has deleterious effects on the myocardium and results in the development of cardiomyopathy. 3 PICM has the following criteria:…”