Left ventricular function and myocardial perfusion before and after cardiac resynchronization therapy in chronic right ventricular apical pacing by echocardiogram-gated myocardial perfusion single photon emission computed tomography

Abstract Introduction The aim of this study was to evaluate the changes in cardiac performance and myocardial blood perfusion by single photon emission computed tomography (SPECT) in patients upgrading to cardiac resynchronization therapy (CRT) from right ventricular apical pacing (RVAP). Methods Eleven patients (age, 70±7.7 years; pacing career, 95±48.8 months) with chronic RVAP were studied. Their baseline characteristics included New York Heart Association (NYHA) class ≥2, with left ventricular end-diastolic volume (LVEDV) >55mm or left ventricular ejection fraction (LVEF) Results Upgrading from RVAP to CRT resulted in an increase in LVEF and a decrease in LVEDV. The standard deviation of the time from the onset of QRS to end-systole in the 17 LV segments, which indicates LV dyssynchrony, showed the tendency to shorten from 98 to 70ms. Furthermore, the %uptake of blood perfusion was increased at the inferoseptal lesion. Conclusion Upgrading to CRT from RVAP improved cardiac function and increased %uptake of blood perfusion at the inferoseptal lesion, as demonstrated by SPECT.