Evaluation of the left ventricular ejection fraction post right ventricular pacing at Inkosi Albert Luthuli Central Hospital (IALCH), Durban, KwaZulu-Natal (KZN).

Abstract

Since the implantation of the first artificial pacemaker in 1958, these devices have become the treatment of choice in bradycardias. Despite its widespread use, only a few studies have looked at the effects of single chamber right ventricular(RV) pacing on left ventricular(LV) function in patients with sinus node dysfunction or atrioventricular node dysfunction. In addition, these studies have produced conflicting results with no consensus reached. Furthermore, the limitation to these studies were the small sample sizes and the absence of sequential echocardiographic monitoring of LV function in each patient. To the best of the authors’ knowledge, no such studies have been conducted in South Africa. This study reviewed data collected from Inkosi Albert Luthuli Central Hospital (IALCH), which is a government hospital in Durban, KwaZulu-Natal (KZN), South Africa. The objective of the study was to evaluate the effects of RV pacing on LV function in a setting where the majority of patients requiring a permanent pacemaker receive single chamber RV apical pacing. The focus of this study was to assess the effect of RV pacing on LV function by assessing the ejection fraction(EF), on echocardiography, pre and post pacemaker insertion. A retrospective chart review of 465 patients managed at the IALCH pacemaker clinic from 2003 up to 2012 was undertaken. Adult patients 18 years and older with a documented EF at the time of insertion of a pacemaker were included in the study. Patients were excluded from the study if they had coronary artery disease (CAD), unrepaired valvular heart disease, atrial fibrillation or dual chamber pacemakers. After enforcing the exclusion criteria, 430 patients were excluded and only 35 patients were eligible for the study. LV dysfunction was pre-defined as a left ventricular ejection fraction (LVEF) of < 50%. This study showed that RV pacing did not have a statistically significant effect on LV function post pacemaker insertion, based on the assessment of EF. The study was limited by the low number of eligible patients as it was a retrospective study and obtaining data was difficult as most patients who require a pacemaker do not routinely have a baseline echocardiograph done prior to insertion of the pacemaker. Another limiting factor in the study was that EF was the only modality of LV function that was assessed. Moreover, evaluation of the EF on echocardiography is subjective and user dependent. International studies have shown that the site of RV pacing has an impact on the degree of LV dyssynchrony and function. This factor could not be assessed in the current study as the site of RV pacing was not documented and was not standardised. Pacing in the correct clinical context is a necessity and is lifesaving. Current literature shows that RV pacing is a safe, relatively simple, convenient procedure that is well tolerated and is effective. This study showed no deterioration in LV function in patients post RV pacemaker insertion, which is important as the RV remains the most common site of lead placement especially in the resource limited state sector. Some studies have reported that RV pacing is associated with LV dysfunction. However, since there is a paucity of level 1 evidence regarding this aspect of RV pacing, the need for prospective studies on the long-term effects of RV pacing on LV function is required. In addition, the impact of alternative pacing sites on LV function should be explored.