title: Prediction of cardiac events in patients having left bundle-branch block with/without chest pain using dipyridamole technetium-99m-sestamibi myocardial perfusion imaging.
abstract: OBJECTIVE
  To determine the prognostic value of myocardial perfusion scintigraphy with dipyridamole stress in patients with preexisting left bundle-branch block (LBBB) with or without chest pain.
  
  
  METHODS
  Seventy-six patients, mean age 53 +/- 10 years, with preexisting LBBB underwent technetium-99m-sestamibi perfusion imaging with dipyridamole infusion protocol (0.56 mg/kg). Stress and rest single photon emission computed tomography (SPECT) images were interpreted by consensus of 2 experienced nuclear medicine physicians and classified as low-risk scans (normal myocardial perfusion scan, small reversible/small fixed defect) and high-risk scans (large, severe, fixed or reversible defect and dilated left ventricle cavity). The patients were followed up for 24 +/- 8 months and occurrences of hard cardiac events (infarction or cardiac death) were noted.
  
  
  RESULTS
  Of the 76 patients, 52 (68%) had low-risk scans and the remaining 24 (32%) had high-risk scans. In the low-risk group, 1 (1.9%) cardiac death and 2 (3.8%) cases of nonfatal myocardial infarction occurred, while in the high-risk group, 5 (20.8%) suffered cardiac death, and 3 (12.5%) nonfatal myocardial infarction. Overall survival rate was 98.1% in the low-risk group compared with 79.2% in the high-risk group with a significant difference of p = 0.034. Negative predictive value of normal myocardial perfusion scintigraphy for the occurrence of death was 100%. No significant difference in survival rate among patients with or without chest pain (p = 0.31) was observed.
  
  
  CONCLUSIONS
  Myocardial perfusion imaging with dipyridamole provided important prognostic information in patients with LBBB; it was useful in stratifying the patients according to cardiovascular morbidity and mortality, and would thus allow the clinician to provide early treatment especially in the high-risk category.
authors.affiliation: Department of Nuclear Medicine, Karachi Institute of Radiotherapy and Nuclear Medicine, Karachi, Pakistan. dr_shajji@yahoo.com
authors.forename: Sharjeel
authors.initials: S
authors.lastname: Usmani
authors.forename: Haider Ali
authors.initials: HA
authors.lastname: Khan
authors.forename: Maseeh-Uz
authors.initials: MU
authors.lastname: Zaman
authors.forename: Kashif
authors.initials: K
authors.lastname: Niyaz
mesh_terms: D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000150:complications / Q000000981:diagnostic imaging*; D002637:Chest Pain / Q000150:complications*; D003326:Coronary Circulation; D004176:Dipyridamole; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D018570:Risk Assessment; D012307:Risk Factors; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi