The Effects of Right Ventricular Apical Pacing Frequency on Left Ventricle Function and Pulmonary Artery Pressure.

Objective: We studied the effect of the frequency of right ventricular (HV) pacing on left ventricle (LV) function pulmonary hypertension.

Background: The incidence of new or worsening pulmonary hypertension after permanent pacemaker (PPM) or implantable cardioverter defibrillator (lCD) lead placement has not been well investigated.

Methods: We reviewed the charts of all patients undergoing PPM or ICD lead placement in our electrophysiology laboratory from December 2007 to December 2012.

Results: Two hundred and six patients (120 with PPM and 86 with ICD) had baseline echocardiography within six months before, and a follow up study at least six months after lead insertion. The mean age was 74 ± 14 years; 56 percent were men. The follow-up period was 29 ± 19 months. RV pacing was associated with a worsening of left ventricular ejection fraction (LVEF) in patients with high frequency of RV (55 ± 16 vs. 44 ± 18; P = 0.001), but not with those with low frequency pacing (55 ± 16 vs. 54 ± 17; P = 0.87). Similarly, RV pacing was associated with a worsening in both right ventricular systolic pressure (RVSP) (42 ± 14 vs. 48 ± 15; P = 0.01) and Pulmonary Artery Systolic Pressure (PASP) (50 ± 17 vs. 56 ± 18; P = 0.005) in patients with high frequency RV, but not in those with low frequency RV pacing [RVSP (43 ± 12 vs. 46 ± 13; P = 0.06) and PASP (51 ± 15 vs. 54 ± 16; P = 0.11)].

Onclusion: PPM or IICD lead implantation worsens LV function and pulmonary hypertension in patients with high frequency of RV pacing frequency. This is probably caused by the mechanical dyssynchrony induced by RV pacing.