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

IntroductionThe 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).MethodsEleven 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) >55 mm or left ventricular ejection fraction (LVEF) <50%, as shown by echocardiography. Cardiac function and cardiac blood perfusion of 17 segments were evaluated by SPECT. Cardio-GRAF (cardio Gated single photon emission computed tomography Regional Assessment for left ventricular Function), a left ventricular (LV) segmental time–volume analyzing program for SPECT, was used to assess dyssynchrony.ResultsUpgrading 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 70 ms. Furthermore, the %uptake of blood perfusion was increased at the inferoseptal lesion.ConclusionUpgrading to CRT from RVAP improved cardiac function and increased %uptake of blood perfusion at the inferoseptal lesion, as demonstrated by SPECT.