Prognostic significance of cardiac (123)I metaiodobenzylguanidine imaging for mortality and morbidity in patients with chronic heart failure: a prospective study.

OBJECTIVE: To determine whether cardiac iodine-123 metaiodobenzylguanidine ((123)I MIBG) imaging is useful in predicting the prognosis of patients with chronic heart failure. DESIGN: Cardiac (123)I MIBG imaging was done on entry to the study. The cardiac MIBG washout rate was calculated from anterior chest view images obtained 20 and 200 minutes after injection of the isotope. Study patients were divided into two groups with washout rates above and below 27% (the mean value + 2 SD obtained in 20 normal subjects), and were then followed up. SETTING: Tertiary referral centre. PATIENTS: 79 patients with chronic heart failure in whom the left ventricular ejection fraction was less than 40%. RESULTS: There were 37 patients in group 1 (washout rate of >/= 27%) and 42 in group 2 (< 27%). During a follow up period of between 1 and 52 months, eight patients died suddenly and five died of worsening heart failure in group 1, while none died in group 2; 13 patients in group 1 and four in group 2 were admitted to hospital for progressive heart failure. Kaplan-Meier analysis showed that group 1 had a significantly higher mortality and morbidity (p = 0.001 and p < 0.001, respectively) than group 2. CONCLUSIONS: Cardiac (123)I MIBG washout rate seems to be a good predictor of prognosis in patients with chronic heart failure.

Abnormal myocardial free fatty acid utilization deteriorates with morphological changes in the hypertensive heart.

The left ventricle's morphological adaptation to high blood pressure is classified into 4 patterns based on mass and wall thickness. The geometric changes caused by maladaptation to pressure overload possibly relate to progression of contractile dysfunction with abnormal energy metabolism. The present study assessed whether the geometric adaptation of the left ventricle (LV) to high blood pressure relates to changes in myocardial energy metabolism, especially free fatty acid (FFA) utilization. Thirty-five patients with essential hypertension underwent echocardiography and dual isotopes myocardial scintigraphy using iodine-123 labeled 15-p-iodophenyl-3-(R,S)-methylpentadecanoic acid (BMIPP, an analogue of a FFA) and thallium-201 (Tl-201). Systolic (endocardial fractional shortening; %FS) and diastolic indices (the ratio of early to atrial filling waves; E/A) of LV function were also assessed. Quantitative myocardial BMIPP uptake was evaluated by the BMIPP/TI-201 myocardial uptake ratio (B/T). The subjects were divided into 4 groups based on LV mass and wall thickness: (1) concentric hypertrophy (CH), (2) eccentric hypertrophy (EH), (3) concentric remodeling (CR), and (4) normal geometry (N). The %FS was lower in the EH group than in the other groups. The mitral E/A ratio in the CH group was lowest. B/T was significantly decreased in the EH group compared with the N group (p < 0.05). B/T correlated with the mitral E/A ratio significantly (p < 0.05, r = 0.42), whereas there was no relationship between %FS and B/T. These results indicate that the geometric changes occurring in hypertensive hearts strongly correlate with alternations in cardiac function and with abnormal myocardial FFA metabolism, and that the latter is associated with diastolic abnormality, but not with systolic function.

Identification of sinus node dysfunction by use of P-wave signal-averaged electrocardiograms in paroxysmal atrial fibrillation: a prospective study.

BACKGROUND: In patients with paroxysmal atrial fibrillation (Paf), the identification of the coexistence of sinus node dysfunction (SND) has therapeutic implications. This study sought to prospectively determine whether SND in patients with Paf would be identified by use of atrial early potential (EP), low-amplitude potentials early in signal-averaged P wave. METHODS: The study population consisted of 149 patients with Paf. Signal-averaged electrocardiography was recorded with the P-wave-triggering technique. The root mean square voltage for the initial 30 MS and the duration of initial low-amplitude signals < 4 microV of signal-averaged P wave were measured in the vector magnitude. The criteria of EP were defined as "the root mean square voltage for the initial 30 MS < 3.0 microV and the duration of initial low-amplitude signals < 4 microV >22 MS." SND was diagnosed by use of the conventional 12-lead electrocardiography, 24-hour Holter monitoring, and bedside electrocardiographic monitoring. RESULTS: Thirty-eight of 149 patients with Paf had EP. Eighteen (47%) of 38 patients with Paf and EP had SND, whereas SND was found in only 5 (5%) of the other 111 patients with Paf without EP (P <.0001). EP gave a sensitivity of 78% and a specificity of 84% for the detection of SND in patients with Paf. CONCLUSION: EP would be useful for the identification of SND in patients with Paf.

Prediction of paroxysmal atrial fibrillation in patients with congestive heart failure: a prospective study.

OBJECTIVES: We sought to prospectively determine whether patients with congestive heart failure (CHF) at risk for paroxysmal atrial fibrillation (PAF) could be identified by clinical and study variables including the P-wave signal-averaged electrocardiogram (P-SAECG). BACKGROUND: Although it is important to assess the risk of developing PAF in patients with CHF, it still remains difficult to predict the PAF appearance in patients with CHF clinically. METHODS: The study group consisted of 75 patients in sinus rhythm without a history of PAF, whose left ventricular ejection fraction, as measured by radionuclide angiography, was <40%. These patients underwent P-SAECG, echocardiography and 24-h Holter monitoring; in addition, the plasma concentration of atrial natriuretic peptide (ANP) was measured at study entry. RESULTS: An abnormal P-SAECG was found at study entry in 29 of 75 patients. In the follow-up period of 21 +/- 9 months, the PAF attacks documented on the ECG significantly more frequently occurred in patients with (32%) rather than without an abnormal P-SAECG (2%) (p = 0.0002). The plasma ANP level was significantly higher in patients with rather than without PAF attacks (75 +/- 41 vs. 54 +/- 60 pg/ml, p = 0.01), although there were no significant differences in age, left atrial dimension or high grade atrial premature beats between the groups. The multivariate Cox analysis identified that the variables significantly associated with PAF development were an abnormal P-SAECG (hazard ratio 19.1, p = 0.0069) and elevated ANP level > or =60 pg/ml (hazard ratio 8.6, p = 0.018). CONCLUSIONS: An abnormal P-SAECG and elevated ANP level could be predictors of PAF development in patients with CHF.

Dispersion of signal-averaged P wave duration on precordial body surface in patients with paroxysmal atrial fibrillation.

AIMS: This study sought to investigate whether the spatial dispersion of signal-averaged P wave duration would be increased in patients with paroxysmal atrial fibrillation, by use of precordial mapping of the P wave signal-averaged ECG. METHODS AND RESULTS: The P wave signal-averaged ECG was recorded by the P wave-triggering method from 16 precordial leads in 55 patients with paroxysmal atrial fibrillation and 57 control subjects. As an index of the dispersion of signal-averaged P wave duration, we obtained the difference between the maximum and minimum in 16 recording sites. The dispersion was significantly greater in the patients with paroxysmal atrial fibrillation than the controls (26.6 +/- 9.5 vs 14.8 +/- 6.7 ms, P<0.0001). In 25 patients with symptomatic attacks of paroxysmal atrial fibrillation, the signal-averaged ECG was repeated 1 h after a single dose of orally administered pilsicainide, a new class Ic drug. These patients were prospectively followed-up for 10 +/- 11 months with pilsicainide. The rate of freedom from recurrence of paroxysmal atrial fibrillation attacks was significantly (P<0.0001) higher in patients with whom dispersion was decreased by the single dose (54%[7/13]) than in those in whom dispersion increased (8%[1/12]). CONCLUSION: Increased dispersion of signal-averaged P wave duration would play an important role in generating paroxysmal atrial fibrillation and would be useful in the prediction of drug efficacy to evaluate the change in dispersion by a single administration of pilsicainide.

Mechanism of impaired left ventricular wall motion in the diabetic heart without coronary artery disease.

OBJECTIVE: To elucidate whether impairment of the myocardial free fatty acid (FFA) metabolism and small vessel abnormalities in the myocardium are etiologic or contributory factors of myocardial dysfunction in patients with NIDDM without any significant coronary artery disease. RESEARCH DESIGN AND METHODS: We performed myocardial imaging with 123I-labeled beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a branched analog of FFA, and dipyridamole-infusion 201thallium scintigraphy (Dip) in nine patients who demonstrated left ventricular wall motion abnormalities without any significant coronary artery disease and in fifteen control cases. As an index of myocardial FFA metabolism, the heart-to-mediastinum count ratio (H/M) of BMIPP was calculated from the mean count in the regions of interest at the heart and the upper mediastinum. RESULTS: Nine patients with reduced wall motion documented by left ventriculography (LVG), (hypokinetic group) demonstrated significantly lower BMIPP uptake (2.1 +/- 0.2, mean +/- SD) than fifteen patients with normal wall motion (normokinetic group) (2.3 +/- 0.2, P < 0.05). Regional ventricular wall motion observed by LVG, regional BMIPP uptake, and regional redistribution phenomenon (RD) were evaluated for five regions of the left ventricle: anterior, septal, apical, lateral, and inferoposterior regions. Wall motion was abnormal in 24 out of 120 regions. Regional BMIPP uptake was reduced in 47 regions. RD in Dip was observed in 23 regions. In regional analysis, the existence of defect in the BMIPP image showed significant correlation with wall motion abnormality (P < 0.01), but there was no significant relationship between the RD in Dip and regional wall motion abnormality (P = 0.16). Myocardial biopsy specimens obtained from the right ventricle of 20 patients showed no pathologic changes, with the exception of two patients. CONCLUSIONS: Our findings suggest that impairment of myocardial FFA metabolism rather than small vessel abnormalities in the myocardium is responsible for modest left ventricular dysfunction in patients with diabetes.

Metabolic changes in hibernating myocardium after percutaneous transluminal coronary angioplasty and the relation between recovery in left ventricular function and free fatty acid metabolism.

To elucidate the changes in oxidative metabolism in hibernating myocardium after coronary revascularization, we performed myocardial single-photon emission computed tomography with a free fatty acid analog, I-123 beta-methyliodophenylpentadecanoic acid (BMIPP), and thallium-201 before and 1 month after percutaneous transluminal coronary angioplasty (PTCA) in 11 patients with angina pectoris caused by single artery stenosis. All patients had improvement in wall motion after PTCA at the region with coronary stenosis; the wall motion abnormality score evaluated by left ventriculography decreased from 5.5+/-0.8 (mean +/- SE) to 2.1+/-0.9, p <0.01) after PTCA. The defect score of I-123 BMIPP images was significantly larger than that of thallium-201 images either before (14+/-1.3 vs 8.9+/-1.1, p <0.01) or 1 month after (7.4+/-1.5 vs 3.7+/-0.8, p <0.01) PTCA. The decrease in the defect score of both images was significant (p <0.01). Changes in the wall motion abnormality score showed a significant correlation with both the change in the defect score of thallium-201 images (r = 0.58, p < 0.01) and that of I-123 BMIPP images (r = 0.75, p <0.01). These results indicate that the metabolism of free fatty acid is impaired in hibernating myocardium, and that improvement in left ventricular function after successful PTCA is strongly associated with the recovery of oxidative metabolism.

Myocardial glucose metabolism in patients with hypertrophic cardiomyopathy: assessment by F-18-FDG PET study.

In an investigation of myocardial metabolic abnormalities in hypertrophic myocardium, the myocardial glucose metabolism was evaluated with F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in 32 patients with hypertrophic cardiomyopathy, and the results were compared with those in 9 patients with hypertensive heart disease. F-18-FDG PET study was performed in the fasting and glucose-loading states. The myocardial regional %dose uptake was calculated quantitatively. The average regional %dose uptake in the fasting state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was significantly higher than that in the patients with hypertensive heart disease (0.75 +/- 0.34%, 0.65 +/- 0.25%, and 0.43 +/- 0.22%/100 g myocardium, respectively). In contrast, the average %dose uptake in the glucose-loading state in the patients with asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy was not significantly different from that in patients with hypertensive heart disease (1.17 +/- 0.49%, 0.80 +/- 0.44% and 0.99 +/- 0.45%, respectively). The patients with apical hypertrophy had also low %dose uptake in the fasting state (0.38 +/- 0.21%) as in the hypertensive heart disease patients, so that the characteristics of asymmetric septal hypertrophy and dilated-phase hypertrophic cardiomyopathy are considered to be high FDG uptake throughout the myocardium in the fasting state. Patients with apical hypertrophy are considered to belong to other disease categories metabolically. F-18-FDG PET study is useful in the evaluation of the pathophysiologic diagnosis of patients with hypertrophic cardiomyopathy.

Prediction of the effectiveness of long-term beta blocker treatment for dilated cardiomyopathy by signal averaged electrocardiography.

OBJECTIVE: To determine whether the effectiveness of long-term beta blocker treatment for idiopathic dilated cardiomyopathy can be predicted by signal averaged electrocardiography (ECG). PATIENTS: 31 patients with dilated cardiomyopathy and without bundle branch block were included in a retrospective study and 16 in a prospective study. METHODS: A signal averaged ECG was recorded before beta blocker treatment, and three variables were measured from the vector magnitude: QRS duration, root mean square voltage for the last 40 ms (RMS40), and duration of the terminal low amplitude signals (< 40 microV) (LAS40). In the retrospective study, these variables were compared among good responders (showing > or = 0.10 increase in ejection fraction 12 months after start of beta blocker treatment) and poor responders without such improvement. The validity of the signal averaged ECG criteria for prediction of the response to beta blocker treatment was examined in the prospective study. RESULTS: In the retrospective study, good responders (n = 16) had a shorter QRS duration (mean (SD): 122.9 (11) v 138 (14.4) ms, p < 0.005) and LAS40 (33.1 (8.9) v 42.5 (7.8) ms, p < 0.005), and a higher RMS40 (31.6 (16.3) v 19.0 (10.3) microV, p < 0.02) than poor responders (n = 15). Signal averaged ECG criteria for good response were defined as two or more of the following: QRS duration < 130 ms, RMS40 > 20 microV, LAS40 < 40 ms (sensitivity 81%, specificity 73%). In the prospective study, six of seven patients who met these criteria showed a good response to the beta blocker treatment, while eight of nine who did not showed a poor response (chi 2 = 6.1, p < 0.02). The signal averaged ECG criteria gave a sensitivity of 86% and a specificity of 89% for predicting the effectiveness of beta blocker treatment. CONCLUSIONS: A signal averaged ECG might be useful in predicting the effectiveness of beta blocker treatment for dilated cardiomyopathy.

Prediction of transition to chronic atrial fibrillation in patients with paroxysmal atrial fibrillation by signal-averaged electrocardiography: a prospective study.

BACKGROUND: It is well known that paroxysmal atrial fibrillation (PAF) often precedes the establishment of chronic atrial fibrillation (CAF). However, there have been no definite methods to predict the transition from PAF to CAF. The purpose of this report was to determine prospectively whether P-wave-triggered signal-averaged ECG (P-SAE) is useful for the prediction of the transition to CAF in patients with PAF. METHODS AND RESULTS: One hundred twenty-two consecutive patients with PAF were prospectively followed after P-SAE, echocardiography, and 24-hour Holter monitoring at study entry. The duration (Ad) and root-mean-square voltage for the last 30 ms (LP30) of the filtered P wave were measured in P-SAE. The abnormality of P-SAE for the prediction of transition to CAF was defined as Ad > or = 145 ms and LP30 < 3.0 microV. Twenty-three (19%; group 1) of the patients had the abnormality of P-SAE, whereas the others (group 2) did not. During the follow-up period (mean, 26+/-12 months), 10 patients (43%) in group 1 acquired CAF, whereas the transition to CAF was observed in only 4 patients (4%) in group 2. Kaplan-Meier analysis revealed that the transition to CAF was significantly observed more often in group 1 than in group 2 (log-rank test, P<.0001). The Cox proportional hazards regression model identified that the variables most significantly associated with the transition to CAF were Ad (chi2=8.6, P=.003) and LP30 (chi2=5.1, P=.02), although significant differences in the left atrial dimension (40.8+/-5.3 versus 37.3+/-5.5 mm, P<.01) and the number of atrial premature contractions (3641+/-4524 versus 1489+/-2895 beats/d, P<.05) were observed between groups 1 and 2. CONCLUSIONS: These results indicate that P-SAE could be useful to identify patients at risk for the transition from PAF to CAF.

A case of hypertensive-diabetic cardiomyopathy demonstrating left ventricular wall motion abnormality.

We report a case of hypertensive-diabetic cardiomyopathy demonstrating left ventricular regional wall motion abnormality, with a normal coronary artery documented on coronary arteriography. Dipyridamole-infusion 201Tl scintigraphy demonstrated transient perfusion defects in the infero-posterior wall of the left ventricle, where reduced wall motion was demonstrated on contrast left ventriculography. Myocardial SPECT (single photon emission tomography) imaging with [123I] beta-methyliodophenylpentadecanoic acid (BMIPP) and 201Tl demonstrated reduced [123I]BMIPP uptake compared with 201Tl uptake in the infero-posterior wall of left ventricle. These results suggest that the impairment of myocardial free fatty acid metabolism is an etiologic or contributory factor for regional wall motion abnormality, together with small-vessel coronary artery disease, in this patient.

Zero flow pressure in human coronary circulation.

UNLABELLED: Coronary pressure flow (P/F) relationship has been investigated mainly from the viewpoint of coronary resistance. However, recent experimental evidence suggests that the zero flow pressure intercept (Pzf) provides important characteristics of coronary circulation. Although Pzf is likely to provide meaningful information about characteristics of coronary circulation, no data are available about Pzf in humans. The authors attempted to determine Pzf in humans by analyzing P/F relationship during long cardiac pause. This relationship, provoked by intracoronary adenosine triphosphate (ATP) infusion, was analyzed in 9 patients (8 men, 1 woman) with coronary heart disease (ages: fifty-six +/- six years). After the diagnostic cardiac catheterization, ATP, 0.6 mg/3 mL, was administrated by bolus intracoronary injection during measurements of coronary blood flow velocity. Coronary blood flow velocity in the left anterior descending artery was measured with a 0.018-inch Doppler angioplasty guide wire (FloWire, Cariometrics, Inc., Mountain View, Calif.). The dynamic P/F relationship was obtained by correlation of the instantaneous aortic pressure and flow velocity with each other at constant intervals. The least square linear regression analysis was applied to the P/F data to yield the extrapolated Pzf axis. Immediately after intracoronary injection of ATP, long pause (5320 +/- 1498 msec) appeared and coronary blood flow velocity decreased to 11 +/- 8 cm/sec. Pzf calculated with P/F relationship was 14 +/- 7 mmHg. CONCLUSIONS: Thus, the results clearly demonstrate that Pzf is higher than right atrial and left ventricular end-diastolic pressure in humans, indicating the complexity of the determinants of the Pzf.

Scintigraphic assessment of silent myocardial ischaemia after early infarction using myocardial SPET imaging with 201Tl and 123I-MIBG.

To test the hypothesis that myocardial sympathetic denervation reflects silent myocardial ischaemia early after infarction, 12 patients with myocardial infarction but without post-infarction angina pectoris underwent single photon emission tomography (SPET) at rest with 201Tl and 123I-metaiodobenzylguanidine (MIBG) shortly after and 3 months after infarction. Short-axis SPET images at the basal, mid-ventricular and apical portions of the left ventricle were selected, and each short-axis image was divided into eight segments. Tracer uptake in each of the 24 segments was scored using a 4-point scale. The total score in each segment was calculated as the defect score for each image, and the difference between the total defect score for the 201Tl and 123I-MIBG images was calculated as the delta defect score. All 12 patients underwent exercise stress 201Tl scintigraphy 1 month after infarction, and they were divided into two groups: those patients with (Group A, n = 7) and those patients without (Group B, n = 5) transient perfusion defects in the peri-infarcted region without chest pain. For the 123I-MIBG defect score, a marked reduction at 3 months was observed in Group A (24 +/- 12 vs 13 +/- 6; P < 0.01), whereas the defect score remained unchanged in Group B (25 +/- 7 vs 23 +/- 8; N.S.). The delta defect score was significantly reduced in Group A (10 +/- 5 vs 6 +/- 4; P < 0.05), whereas it remained unchanged in Group B. The 123I-MIBG defect score early after infarction was higher than the exercise-induced 201Tl defect score (24 +/- 12 vs 20 +/- 9; P < 0.01), whereas at 3 months post-infarction it was lower than the exercise-induced 201Tl defect score (13 +/- 6 vs 20 +/- 9; P < 0.05). Moreover, effort chest pain during daily activities was noted in 5 of the 7 (71%) patients in Group A within 3 months post-infarction. The results of this study suggest that viable but denervated myocardium (mismatched 123I-MIBG defects) is present in peri-infarcted regions, and that myocardial sensory nervous disturbance, which may co-exist with sympathetic nervous denervation, may induce silent myocardial ischaemia in patients with myocardial infarction.

Usefulness of dipyridamole-thallium imaging in 257 patients with atherosclerotic vascular disease.

We evaluated the usefulness of dipyridamole-thallium imaging for the detection of ischaemic heart disease in 257 patients with atherosclerotic vascular disease (80 patients with arteriosclerosis obliterans, 81 patients with aneurysm of the abdominal aorta, 60 patients with aneurysm of the thoracic aorta and 36 patients with dissecting aortic aneurysm). Clinical evidence of ischaemic heart disease was found in 69 of 257 (27%) patients, including 32 patients with arteriosclerosis obliterans, 23 with aneurysm of the abdominal aorta, 9 with aneurysm of the thoracic aorta and 5 with dissecting aortic aneurysm. Dipyridamole-thallium imaging identified myocardial ischaemia in 49 of 69 (71%) patients with clinical evidence of ischaemic heart disease. Dipyridamole-thallium imaging showed positive results in 67 of 81 (83%) patients with aneurysm of the abdominal aorta. In patients with no clinical evidence of ischaemic heart disease, the results of dipyridamole-thallium imaging were positive in 39 of 188 (21%) patients. Dipyridamole-thallium imaging was positive in 90 of the 257 (35%) patients as a whole. When we combined the patients with positive dipyridamole-thallium imaging with those with negative dipyridamole-thallium imaging but who had clinical evidence of ischaemic heart disease, 42% of all patients had evidence of ischaemic heart disease. Our findings suggest that atherosclerotic vascular disease is strongly associated with ischaemic heart disease and that dipyridamole-thallium imaging is useful for the detection of ischaemic heart disease.

A technique for changing a PTCA balloon catheter over a regular-length guidewire.

In 100 patients who underwent coronary angioplasty with more than one balloon catheter for a lesion, these over-the-wire balloon catheters were changed by using a regular-length guidewire. In order to change to another balloon, the inflation device was connected to the central guide wire lumen of the catheter after pulling back the catheter until the proximal end of the regular length guide wire disappeared. By pulling back the balloon catheter from the guiding catheter by applying a pressure with the inflation device, the balloon was taken out of the guiding catheter leaving the wire in the coronary artery. One hundred forty-nine of 163 attempted procedures were completed successfully. Our technique helped in performing a fast, safe, and reliable changing procedure compared to the procedure with an extended guidewire.

[Myocardial washout of 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) at exercise myocardial scintigraphy in patients with ischemic heart disease].

Myocardial washout of the new myocardial perfusion imaging agent, 99mTc-hexakis-2-methoxy isobutyl isonitrile (99mTc-MIBI) was studied in 23 patients with coronary artery disease. These patients were divided into three groups; 8 patients with effort angina pectoris (AP group), 6 with myocardial infarction who had reversible defect (MI-RD (+) group) and 9 with myocardial infarction who had not reversible defect (MI-RD (-) group). Regional radioactivities were determined with postexercise 1- and 3-hour myocardial planar images. In AP group, 99mTc-MIBI washout rate in ischemic area was smaller than in normal area (3.8 +/- 7.5% vs. 8.3 +/- 5.6%, p < 0.05), however, in the remaining two groups, there were no difference in washout between normal and infarct areas. Defect/normal ratios from postexercise 1 hour to 3 hours were slightly increased in AP and MI-RD (+) groups. Our results indicate that 99mTc-MIBI showed slight and incomplete myocardial redistribution in ischemic areas. These data showed to be considered in the interpretation of 99mTc-MIBI myocardial imaging.

Clinical results with beta-methyl-p-(123I)iodophenylpentadecanoic acid, single-photon emission computed tomography in cardiac disease.

This study was undertaken to evaluate the relationships, between myocardial perfusion and metabolism. Simultaneous beta-methyl-p(123I)iodophenylpentadecanoic acid (123I-BMIPP) and thallium 201 myocardial single-photon emission computed tomography (SPECT) were performed in 25 patients with myocardial infarction (group A) and 16 patients with hypertrophic cardiomyopathy (group B). The severity scores of 123I-BMIPP and 201Tl myocardial SPECT images were evaluated semiquantitatively by segmental analysis. In Group A, dissociations between thallium- and 123I-BMIPP-imaged defects were frequently observed in patients with successful reperfusion compared with those with no reperfusion and those with reinfarction. In four patients with successful reperfusion, repeated 123I-BMIPP and 201Tl myocardial SPECT showed gradual improvement of the 123I-BMIPP severity score compared with the thallium severity score. In group B, dissociations between thallium- and 123I-BMIPP-imaged defects were also demonstrated in hypertrophic myocardium. In addition, nonhypertrophic myocardium also had decreased 123I-BMIPP uptake. In groups A and B, 123I-BMIPP severity scores correlated well with left ventricular function compared with thallium severity scores. These findings indicate that 123I-BMIPP is a suitable agent for the assessment of functional integrity, because left ventricular wall motion is energy dependent and 123I-BMIPP may reflect an aspect of myocardial energy production. This agent may be useful for the early detection and patient management of various heart diseases as an alternative to positron emission tomographic study.

[Simultaneous assessment of exercise-induced abnormalities in myocardial perfusion and regional wall motion by using 99mTc-tetrofosmin].

To clarify the usefulness of the combined assessment of exercise (EX)-induced abnormalities in myocardial perfusion and regional wall motion for detecting coronary artery disease (CAD), we carried out first-pass radionuclide angiography and myocardial perfusion imaging during EX and at rest by 99mTc-tetrofosmin. Twenty-four patients with angiographically proven CAD, 9 (Gp A) with single and 15 (Gp B) with multivessel disease, were studied. The sensitivity for the detection of CAD was 78% of Gp A, 73% of Gp B in planar image and 78%, 87% in SPECT image, respectively. When left ventricular ejection fraction and regional ejection fraction (rEF) were combined with the result of myocardial perfusion, sensitivity increased up to 89% of Gp A, 100% of Gp B. Diagnostic accuracy of LAD, LCX and RCA was 79%, 88% and 83%, respectively. Regional EF in ischemic areas decreased during EX in both Gps, particularly in Gp B. Regional EF in relatively normal perfusion areas did not significantly change in Gp A, but decreased in Gp B. These results suggest that 99mTc-tetrofosmin contributes to the improvement of sensitivity for CAD by combined assessment of EX-induced wall motion and myocardial perfusion abnormalities.

Discrepancies between myocardial perfusion and free fatty acid metabolism in patients with hypertrophic cardiomyopathy.

To test the hypothesis that there are discrepancies between 201Tl- and 123I-beta-methylpentadecanoic acid (BMIPP) distribution in the left ventricular myocardium and to assess whether BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy (HCM), myocardial single photon emission computed tomography (SPECT) was performed with 201Tl and BMIPP in five normal subjects and 12 patients with asymmetric septal hypertrophy. Tracer uptake in the left ventricular myocardium was scored using a four-point grading system. A homogenous distribution of the tracer with no discrepancy between 201Tl and BMIPP uptake in the left ventricular myocardium was observed in each normal subject. In contrast, BMIPP uptake was reduced compared to 201Tl in 58 segments (40%) of the 144 myocardial segments in patients with HCM. Such discordant BMIPP uptake was observed in 15 segments (42%) of the septal segments, in 19 segments (53%) of the anterior segments, in eight segments (22%) of the lateral segments, and in 16 segments (44%) of the inferior segments. There was no significant correlation between 201Tl perfusion score and left ventricular ejection fraction, whereas there was a significant correlation between BMIPP perfusion score and left ventricular ejection fraction (r = 0.748; P < 0.01). The results indicated that there were discrepancies between 201Tl and BMIPP uptake in a significant proportion of myocardial segments, suggesting the impairment of fatty acid metabolism and that BMIPP is a useful tracer agent for the assessment of left ventricular function in hypertrophic cardiomyopathy.