Usefulness of myocardial perfusion SPECT in patients with left bundle branch block and previous myocardial infarction.
BACKGROUND
The diagnostic value of myocardial perfusion scintigraphy in patients with left bundle branch block (LBBB) and previous acute myocardial infarction has not been evaluated.


OBJECTIVE
To determine the utility of single photon emission computed tomography (SPECT) in patients with LBBB and previous acute myocardial infarction.


METHODS
Seventy two consecutive patients with permanent LBBB and previous acute myocardial infarction were studied with stress-rest SPECT using 99mTc compounds. The same stress procedures were followed in all patients: (1) exercise alone when it was sufficient; (2) exercise plus simultaneous administration of dipyridamole if exercise was insufficient.


RESULTS
In 26 of 28 patients (93%) who had a Q wave acute myocardial infarct before the development of LBBB, there was concordance between abnormal Q waves and rest SPECT in the localisation of myocardial necrosis (kappa = 0.836; p = 0.0001). In 48 patients who had coronary angiography, the positive predictive value of exercise (+dipyridamole) myocardial SPECT for the diagnosis of left anterior descending coronary artery stenosis was 93%, for left circumflex coronary artery stenosis, 96%, and for right coronary artery stenosis, 89%. Specificity values were 83%, 91%, and 69%, respectively. However, sensitivity (69%, 64%, and 89%) and negative predictive values (48%, 46%, and 82%) were suboptimal.


CONCLUSIONS
Rest myocardial perfusion SPECT with technetium compounds is useful for localising healed myocardial infarction in patients with LBBB, and exercise (+dipyridamole) SPECT has a high positive predictive value and specificity for the diagnosis of coronary stenosis in these patients.
Candell-Riera
J
J
Department of Cardiology, Hospital Universitari Vall d'Hebron, Barcelona, Spain. jcandell@hg.vhebron.es
Oller-Martínez
G
G
Pereztol-Valdés
O
O
Castell-Conesa
J
J
Aguadé-Bruix
S
S
Soler-Peter
M
M
Simó
M
M
Santana-Boado
C
C
Soler-Soler
J
J
D000368:Aged; D000704:Analysis of Variance; D002037:Bundle-Branch Block / Q000000981:diagnostic imaging*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014665:Vasodilator Agents
D009943:Organophosphorus Compounds; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; C078700:technetium tc-99m tetrofosmin; D004176:Dipyridamole