Thalium perfusion in patients with left bundle branch block in relation to left ventricular asynchrony

Epidemiological studies have identified LBBB as an independent factor for cardiac mortality.( Baladasseroni S ., et al 2002 ) . In general population LBBB has an incidence of 1-3 % this incidence increase to 30% in patients with heart failure. ( Baladasseroni S ., et al 2002 )This study was designed to assess if LBBB causes LV dilatation and /or septal hypo perfusion as detected by Echo-cardiography & stress Thallium perfusion imaging respectively in patients with LBBB & normal ( CA ) & their possible relation to LV asynchrony as detected by QRS duration.We studied 40 patients with complete constant LBBB in cardiology department of Zagzig university & National Heart Institute Perfusion Scan Unit . All patients were subjected to twelve lead ECG , stress Thallium-201 myocardial perfusion imaging with dipiridamole , CA and echocardiography .There was a significant number of patients who had reversible antro septal perfusion defect in stress Thallium-201 myocardial perfusion imaging in patients with LBBB.There was a significant increase in LVES diameter and S thickness with significant decrease in LV EF % and FS % as detected by echocardiography in patients with LBBB .Patients who had perfusion defects in stress Thallium-201 myocardial perfusion imaging showed more increase in LVES diameter and S thickness with more decrease in LV EF % and FS than those who did not have such defect.There was a significant correlation between increase in QRS duration & Dipiredamole stress imaging defect.There was a significant correlation between increase in QRS duration & LVES diameter , S thickness , LV EF % and FS %.LBBB causes hypoperfusion to the antroseptal region with no visible implications on CA and also causes LV dilatation which is related to the degree of LV asynchrony.