Myocardial viability assessment by endocardial electroanatomic mapping: Comparison with metabolic imaging and functional recovery after coronary revascularization

OBJECTIVES The objective of this study was to compare electroanatomic mappi ng for the assessment of myocardial viability with nuclear metabolic imagin g using positron emission computed tomography (PET) and with data on functi onal recovery after successful myocardial revascularization. BACKGROUND Animal experiments and first clinical studies suggested that ele ctroanatomic endocardial mapping identifies the presence and absence of myo cardial viability. METHODS Forty-six patients with prior (greater than or equal to2 weeks) myo cardial infarction underwent fluorine-18 fluorodeoxyglucose (FDG) PET and T c-99m sestamibi single-photon emission computed tomography (SPECT) before m apping and percutaneous coronary revascularization. The left ventricular en docardium was mapped and divided into 12 regions, which were assigned to co rresponding nuclear regions. Functional recovery using the centerline metho d was assessed in 25 patients with a follow-up angiography. RESULTS Regional unipolar electrogram amplitude was 11.0 mV +/- 3.6 mV in r egions with normal perfusion, 9.0 mV +/- 2.8 mV in regions with reduced per fusion and preserved FDG-uptake and 6.5 mV +/- 2.6 mV in scar regions (p < 0.001 for all comparisons). At a threshold amplitude of 7.5 mV, the sensiti vity and specificity for detecting viable (by PET/SPECT) myocardium were 77 % and 75%, respectively. In infarct areas with electrogram amplitudes >7.5 mV, improvement of regional wall motion (RWM) from -2.4 SD/chord +/- 1.0 SD /chord to -1.5 SD/chord +/- 1.1 SD/chord (p < 0.01) was observed, whereas, in infarct areas with amplitudes <7.5 mV, RWM remained unchanged at follow- up (-2.3 SD/ chord +/- 0.7 SD/chord to -2.4 SD/chord +/- 0.7 SD/chord). CONCLUSIONS These data suggest that the regional unipolar electrogram ampli tude is a marker for myocardial viability and that electroanatomic mapping can be used for viability assessment in the catheterization laboratory. CT Am Coil Cardiol 2001;38:91-8) (C) 2001 by the American College of Cardiolog y.