IACC February 1996 • Influence of Coronary Micravascular Dysfunction on Left Ventdcufar Contractile Response to Cathecholamine in Dilated Cardiomyopathy Makoto Onishi, Tomohiro Kondo, Masato Mefita, Tohru Adi, Negao Yasutomi, Tadaaki Iwasald. Hyogo College of Medicine, Nishinomiya, Japan We attempted to clarify the influence of coronary microvascular dysfunction on left vantdcular contractile response to dobutamine (DOB) administration in 12 patients with dilated cardiomyopathy (DCM) using DOB stress 201 thallium-SPECT (DOB-TI) and myocardial contrast echocardiography(MCE). Methods: 1 ) The echocardiographic assessment of left ventricular contractility was done by contedine method before and after DOB(10F) administration at mfd-papillary muscle level. 2) MCE: The sonicated 5=/0 human serum albumin (2 ml) was injected into left coronary artery, and the background subtracted peak intensity (API) and the washout half-time 0"1/2) of contrast enhancement were measured at the same level. 3) DOB-TI (DOB: 10),) .'1"1 uptake was scored from 0 (defect) to 3 (normal). Total TI uptake score of left venfdcle in which was divided into 9 segments was calculated before and after DOB infusion. Results: 1) The contractility responded normally to DOB in 7 of 12 patients (Group 1). The remaining 5 patients (Group 2) showed impairment of response to DOB, However, no significant difference was found between the 2 groups in left vehicular contractility before DOB infusion. 2) MCE: The higher ApI and the shorter T1/2 were observed in Group 1 compared with those in Group 2 (p < 0.01). 3) TI uptake scorn immediately after DOB stress was significantly lower in Group 2 than in Group 1(22 ± 4 vs. 16 =1: > 0.01). TI uptake scorn did not differ between the 2 groups before DOB infusion. Conclusion: These results suggest that myocardial ischemia based on microvascular dysfunction is involved in reduced responseto cathecholamine in DCM. ~'----~ The Relation Between Thallium-201 Uptake and Contractile Reserve Elicited With Isolated or Combined Adranergic and Adenosinerglc Stimulation in Viable Myocurdium Albert Verge, Miedrag Ostojio, Rosa S~..ad,Alessandro P~ngitore, Alassta Gimalli, Ana Djordjevic-Dikic, Ivana Nedeljkovic, Marco Tones, Panto Marzullo. Eugenio Picano. CNR, Institute of Clinical Physiology. Pisa, Italy We have pmviousty shown that infra-low (0.28 mg/Kg) dipyddamole (DIP) added to low dose (up to 10 mcg/Kg/min) (DOB) recruits an inotropic reserve in asynergic segments which were non-msponder either after DOB or DIP alone and destined to recover following revaseuladzation. In order to investi- gate the relationship between radioisetopic and echocardiographic markers of myocardial viability, 24 patients (mean age 60 4- 9 years) with previ- ous myocardial infarction (> 3 months), angiographically assessed coronary artery disease (5 with 1 -, 10 with 2- and 9 with 3-vaseel disease) and resting dysfunction (mean ejection fraction 37 ± 12%) underwent rest-redistdb~on planar 201-Thallium scintigraphy (Th), and low dose pharmacological stress echo with DOB, DIP and combined DIP and DOB (DIDO). Critsda for via- bility in a 13 segment model were: percentage peak activity < 55=/= for Th; decrease in wall motion scorn >_ 1 grade (1 = normal to 4 = dyaldnefi¢)for stress echo. A regional resting dyssynergy was observed in 167 segments; of these, 128 were viable by Th (78=/=) 93 by DOB (56%; p < 0.001 vs Th), 65 by DIP (51%; p < 0.001 vs Th), and 120 by DIDO (72%, p = ns vs Th). The rate of agreement between Th and stress echo was 71% for DIP, 73% for DOB and 86% for DiDO (p < 0.001 vs DiP and vs DOB). In conclusion DIDO recruits an inotropic reserve in a significant proportion of segments with resting dysfunction which were non-msponders either after DIP or DOB alone and pmsen/ed Th uptake. ~"~'~ Akineeis Becoming Dyskinesis at High-Does Dobutamlne Stress Echocardlography: A Marker of Poor FunctionalRecoveryAfter Myocardial Revescularlzation Abdou Ethandy, Jan H. Cornel, Jos R.T.C. Roalandt, Ron T. van Domburg, Galal M. El-Said, Mohammed M. Ibrahim, Panlo M, Fioretti. Thoraxcenter, Rotterdam, The Netherlands Aldnesis becoming dyskinesis at high dose dobutamine has been disre- garded as a marker of myocardial iscbemia. However, the relation between this pattern and myocardial viability has not been studied. 42 patients with old myocardial infarction underwent dobutamine stress echocardiography (up to 40/zg/kg/min) before coronary artery bypass surgery, and resting echocm'- diogram 3 months after surgery.Viability in akinetio segments was considered if systolic thickening occurred at low-dose dabutamine (LDD). During high dose dobutamine, dyskinesis occurred in 35 of the 164 akinetic segments ABSTRACTS- Poster 99A (group A). The remaining 129 segments comprised group B. Segments of group B had a higher prevalence of viability pattom at LDD (18=/= vs 0%, p < 0.01) and functional improvement (20% vs 0%, p < 0.005) compared to group A. In absence of viability paftem at LDD, postoperative improvement occurred in 10% of segments in group B and in none in group A, msulti'~g in a higher negative predictive value of LDD in group A versus B (100°/= vs 90%, p < 0.05). Conclusion: Akinesis becoming dyskincsis at high dose dobutamine echo- cardiography is associatedwith poor functional outcome after revesculadza- lion. Observation of this pattsm provides additional data to those obtained at LDD and improves the value of dobutamine echocerdiography for prediction of functional improvementof akinetio segments. Low Does_. Dobutamine Stress Echocurdiography uan Predict Improvement in Left Ventrlcular Ejection Fraction After Reveecularization David A. Cusick, Gorsv Ailawedi, James W. Frsdefickson, Michael J. Vooesh, Robert O. Bonow, Farooq A. Chaudhry. Noffhwestem University, Chicago, IL Low dose dobutaminestress echocardiography (DSE) can identify potentially viable myocardium in pts with coronary artery disease and LV dysfunction. In such pts, LV dysfunction may improve after coronary artery bypass surgery (CABG). However,whether ~is translates into meaningfutincrease in overall LV ejection fraction (LVEF), and whether pestup LVEF can be predicted, has not been demonstrated.We therefore studied 15 consecutive lOtS (mean age 65 yrs; range 47-81; 13 males, 2 females) with coronary artery disease and LV dysfunction who underwent DSE pdor to CABG. LVEF was measured using a biplane aree-langth method at baseline, dudng low dose DEE, and after CABG (mean days after CABG 65). Two pts died pedoparativaly and thus pest CABG LVEF is not available. Results: No Mean LVEFL(%) Baseline LowDose DSE Post CABG '~3 32+5 45 :E7" 43±6* Them was no significant dilfemnce in mean LVEF between low dose DSE and pest CABG. Low dose DSE correlated with post CABG LVEF (r = 0.87, p <: 0.001), and the mean difference between low d,~seDSE and pest CABG LVEF was -2.5 4- 3 5. Conclusion: These data indicate that low dose DSE can predict not only the recovep/of LV segmental function but also whether a clinically relevant change in global LVEF will occur following CABG. [•-• The Timing of .O.obutamine Echocardiography After Acute Myocaraial Infarction Does Not Alter the Accuracy for Detecting Reversible Dysfunction Stovan c, Smart, Thomas Knickelbine, John Wynsen, Kiran B. Sagar. Medical College of Wisconsin. Milwaukee, Wl Regional mycoardia func~on has been shown to change dudng the first week after acute myocmdial infarction(MI). To investigate if the liming of dobutamine echcoardiegruphy(DE) affects accuracy for mvers~le dysfunc- tion, 115 patients (age 57:1:13 yrs, 17 woman/98 men, 66 withth Q-wave infarction, 64 anterior infarction, and 80 treated with thmmbelysts) undenvent low dose DE (rest, 5 and 10 mg/kg/min in 5-10 rain stages) at 5 ± 2 days (range 2-7) after acute MI. Follow-up echsoan:liogrsphywas performed at 2 4-1 months after infarction. All echocardiograms were analyzed according to the standard model and sconeg system. Reversible dysfunction was defined as improved infarction zone wall thickening at follow-up and dobutamine responsive as improved thickening during low dose infusion. Infarction zone dysfunction reversed at follow-up in 65 (57°/o) patients and responded to low dose dobutomine in 65 (57%). The sansilivity and specifcity of DE for reversible dysfunction were 91% (50/65) and 86% (43/50), respectively. The interval between MI and DE was 2 days in 16 patients, 3 days in 24, 4 days in 24, 5 days in 12, 6 days in 16, and 7 days in 23. Hemodynamics were similar in each subset. The number of patients with reversible and fixed dysfunction and the sensitivity and specificity of DE asco~ng to the interval were as follows" Interval (days) 2 3 4 5 6 7 Reversible (n) 11 15 12 7 6 14 Rxecf (n) 5 9 12 5 10 9 Sensitivity (%) 82 93 92 1CO 83 93 Spe~flc~y (%) 80 100 67 80 100 89 Them were no differences in sensitivity and specificityrelated to the interval to DE. In conclusion, the timing of DE after acute MI does not affect its sensitivity or specificity for reversible dysfunction.