Myocardial blood flow assessment with (82)rubidium-PET imaging in patients with left bundle branch block

Author(s)

Falcao, Andrea ^[1] ; Chalela, William ^[1] ; Giorgi, Maria Clementina ^[1] ; Imada, Rodrigo ^[1] ; Soares, Jr., Jose ^[1] ; Do Val, Renata ^[1] ; Oliveira, Marco Antonio ^[1] ; Izaki, Marisa ^[1] ; Kalil Filho, Roberto ^[1] ; Meneghetti, Jose C. ^[1]

Affiliation

^[1] Univ Sao Paulo, Fac Med, Hosp Clin, Inst Coracao InCor, Serv Med Nucl & Imagem Mol, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Clinics; v. 70, n. 11, p. 726-732, 2015.
• Web of Science Citations: 0

Abstract

OBJECTIVES: Perfusion abnormalities are frequently seen in Single Photon Emission Computed Tomography (SPECT) when a left bundle branch block is present. A few studies have shown decreased coronary flow reserve in the left anterior descending territory, regardless of the presence of coronary artery disease. OBJECTIVE: We sought to investigate rubidium-82 (Rb-82) positron emission tomography imaging in the assessment of myocardial blood flow and coronary flow reserve in patients with left bundle branch block. METHODS: Thirty-eight patients with left bundle branch block (GI), median age 63.5 years, 22 (58%) female, 12 with coronary artery disease (>= 70%; GI-A) and 26 with no evidence of significant coronary artery disease (GI-B), underwent rest-dipyridamole stress Rb-82-positron emission tomography with absolute quantitative flow measurements using Cedars-Sinai software (mL/min/g). The relative myocardial perfusion and left ventricular ejection fraction were assessed in 17 segments. These parameters were compared with those obtained from 30 patients with normal (82) Rb-positron emission tomography studies and without left bundle branch block (GII). RESULTS: Stress myocardial blood flow and coronary flow reserve were significantly lower in GI than in GII (p<0.05). The comparison of coronary flow reserve between GI-A and GI-B showed that it was different from the global coronary flow reserve (p<0.05) and the stress flow was significantly lower in the anterior than in the septal wall for both groups. Perfusion abnormalities were more prevalent in GI-A (p=0.06) and the left ventricular ejection fraction was not different between GI-A and GI-B, whereas it was lower in GI than in GII (p<0.001). CONCLUSION: The data confirm that patients with left bundle branch block had decreased myocardial blood flow and coronary flow reserve and coronary flow reserve assessed by Rb-82-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block. (AU)