Mechanism of Pacemaker-Induced Left Ventricular Dysfunction: Study Protocol

A permanent pacemaker (PPM) is currently the definitive treatment for patients with a total atrioventricular block (TAVB). The number of pacemaker implantation has been increasing every year. However, PPM implantation increases the risk of developing left ventricular (LV) dysfunction and becoming pacemaker-induced cardiomyopathy (PICM). There has never been a published study on the cellular mechanism of LV dysfunction caused by PPM implantation. The mechanism of pacemaker-induced left ventricular dysfunction (PILVD) study is a multi-center, quasi-experimental, etiognostic study with a time-series design. This etiognostic study aims to investigate the mechanism of cellular level changes in TAVB patients who had PPM implanted. In particular, the difference in serum miR-155 levels and plasma levels of IL-6, sTNFR-2, MMP-9, N-Cad, and ZO-1 in TAVB patients had LV dysfunction caused by right ventricular dysfunction septal PPM implantation measured by global longitudinal strain (GLS) obtained from echocardiography. Blood samples and echocardiographic examinations will be performed on patients who satisfied the inclusion criteria prior to pacemaker implantation, one month after, and three months following pacemaker implantation. The ELISA method will be used to assess IL-6, sTNFR-2, MMP-9, ZO-1, and N-Cad from plasma samples. MiR-155 levels in serum will be determined using the reverse-transcriptase polymerase chain reaction (RT-PCR) technique. The main findings are a decrease in serum miR-155 levels and increased plasma IL-6, sTNFR-2, MMP-9, N-Cad, and ZO-1 levels in TAVB patients who developed LV dysfunction due to right ventricular septal pacemaker implantation measured by GLS at 1 and 3 months.