Key result
Left bundle branch block was associated with significantly lower stress myocardial blood flow and coronary flow reserve compared to controls without left bundle branch block (p<0.05).
Why the study?
Does 82Rb-PET imaging detect differences in myocardial blood flow and coronary flow reserve in patients with left bundle branch block compared to normal controls?
Observational (n=68)
Does 82Rb-PET imaging detect differences in myocardial blood flow and coronary flow reserve in patients with left bundle branch block compared to normal controls?
p-value: p=<0.05
Rubidium-82 PET imaging demonstrates that patients with left bundle branch block have decreased myocardial blood flow and coronary flow reserve, which may help identify concurrent coronary artery disease.
LBBB-associated reductions in stress MBF and CFR support microvascular involvement; leaves open prognostic and therapeutic implications.
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 (82Rb) 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 82Rb-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 82Rb-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 82Rb-positron emission tomography imaging may be useful in identifying coronary artery disease in patients with left bundle branch block.
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Falcão et al. (2015) conducted an observational in Left bundle branch block (n=68). Left bundle branch block vs. Normal 82Rb-PET studies without left bundle branch block was evaluated on Stress myocardial blood flow and coronary flow reserve (p=<0.05). Left bundle branch block was associated with significantly lower stress myocardial blood flow and coronary flow reserve compared to controls without left bundle branch block (p<0.05).
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