The efficacy of steroid therapy for active myocarditis is controversial, so a new scoring system was constructed based on 6 clinical parameters: (1) the mode of onset of the disease; (2) complications of immune-related systemic disorders; (3) evidence of viral infection; (4) the population of infiltrating inflammatory cells; (5) the appearance of multinucleated giant cells in endomyocardial biopsy specimens; and (6) the duration of active myocarditis. Points from -2 to +2 were assigned to each parameter and the total score was calculated from the 6 parameters. Twenty-one patients with clinically suspected myocarditis, who had been admitted to hospital from 1987, were retrospectively analyzed by this scoring system. Sixteen patients were treated without corticosteroids at presentation, and 5 patients were treated by conventional methods with adjunctive use of corticosteroids. In 10 patients of the non-steroid group myocarditis improved and their mean score was -4.8 at presentation. In 6 patients of the non-steroid group, myocarditis and cardiac symptoms persisted after initial therapy, and their score at presentation was -0.8. In 2 patients of the steroid group myocarditis improved after initial therapy and their score was +2. In 2 other patients of the steroid group, myocarditis and cardiac symptoms persisted and their score was +3. Another patient of the steroid group died from congestive heart failure and his score was -5 at presentation. In 8 of 9 patients with persistent myocarditis, the secondary phase therapy was challenged. Seven patients were treated with corticosteroids and 6 patients improved. Their score at the secondary phase was +2.5. Overall, non-steroid conventional treatment was successful in patients with the scores from -5 to -4, and steroid therapy succeeded in patients with scores from 0 to +6. Although this is a retrospective study, this scoring system is able to predict the efficacy of steroid therapy in patients with clinically suspected active myocarditis. (Jpn Circ J 1998; 62: 715 - 720)

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The relationship between autonomic nervous system activity (ANA) and coronary vasoreactivity during transient myocardial ischemia was determined in patients with vasospastic angina (VA). ANA was measured by power spectral analysis of heart rate variability and humoral factors following intravenous infusion of insulin in 24 patients with VA and 6 control patients. Nine (38%) of the VA patients had significant ST segment depression (STD), and 4 of these patients had symptomatic STD. The frequency of anginal episodes in the 9 patients with VA and STD was significantly greater than that in the 15 VA patients without STD (3.4±3.1 vs 0.5±0.8 episodes/week, p<0.05). The increase in the LF/HF ratio 30 min after insulin injection in patients with STD was significantly greater than that in patients without STD (34±31% vs 4±34%, p<0.05). All of the patients with VA and STD had significant coronary vasospasm in response to the infusion of ≤20 μg of acetylcholine, higher levels of nocturnal parasympathetic activity, and greater norepinephrine production in response to insulin stimulation than the VA patients without STD. These findings suggest that increased vagal tone and hyperreactivity to adrenergic stimulation may trigger vasospasm in patients with VA. (Jpn Circ J 1998; 62: 721 - 726)

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The purpose of this study was to determine the efficacy of long-term pharmacological therapy selected on the basis of a head-up tilt test (HUT) in patients in whom reproducibility of the HUT response was demonstrable in the initial study. The HUT (80° upright) was performed for 15 min with or without an infusion of isoproterenol (0.01-0.03 μg/kg per min) in 54 patients with recurrent unexplained syncope. When vasovagal syncope was induced (positive response), the HUT was repeated to examine the test reproducibility. Vasovagal syncope was induced in 24 patients during HUT alone, and in 30 patients during the HUT with isoproterenol. Acute reproducibility was observed in 49/54 (91%) patients. In the tilt-positive patients, HUT was repeated after an intravenous administration of propranolol (0.1 mg/kg) or disopyramide (1 mg/kg) (acute test). Propranolol proved effective in 21 (80%) of 26 patients, and disopyramide in 13 (56%) of 23 patients. Thereafter, evaluation was done on the long-term clinical follow-up of the pharmacological intervention selected on the basis of the acute test in the 34 patients in whom the HUT could not induce vasovagal syncope after the oral administration of the pharmacological agent (propranolol 60 mg/day, disopyramide 300 mg/day). Thirty-two of 34 patients (94%) did not develop syncopal attacks during a 44±12-month period. Thus, in patients with unexplained syncope, HUT appears to have a high degree of acute reproducibility, and the acute drug response guided by HUT may be used to develop an effective long-term pharmacological therapy. (Jpn Circ J 1998; 62: 727 - 732)

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Holter ECG was used to evaluate changes in heart rate variability (HRV), indicators of the autonomic nervous system, and arrhythmia before and after radiofrequency (RF) catheter ablation in patients with symptomatic supraventricular tachycardia. Ablation targets in 43 patients included the atrioventricular (AV) nodal pathway (AVNRT, n=17), a right free wall accessory pathway (n=10), a septal accessory pathway (n=6), and a left free wall accessory pathway (n=10). The High freguency component (0.15 - 0.40 Hz) or pNN50 of HRV analysis, indicating parasympathetic activity, significantly decreased immediately after RF ablation in the AVNRT and septal accessory pathway groups, but not in the right or left wall groups. In contrast, in all four groups, ventricular premature contractions (VPCs) significantly increased in most of the patients, and ventricular tachycardia occurred in a few of the patients immediately after RF ablation. There was no serious arrhythmia. These alterations in HRV analysis and arrhythmia returned to the control level after 1 week or more. VPCs after RF ablation did not consistently increase as a result of the reduced parasympathetic tone activity, but at the lesion near the conduction system, the increase in VPCs was inhibited by higher parasympathetic tone activity, because the parasympathetic nerve fibers and receptors were distributed in these lesions. (Jpn Circ J 1998; 62: 733 - 740)

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In heart failure with low cardiac output, exercise tolerance is reduced despite modulated regional blood distribution and oxygen extraction. However, low cardiac output does not necessarily lead to reduced exercise tolerance especially during mild exercise. In the present study, in order to understand the mechanisms regulating exercise tolerance in heart failure, we measured oxygen consumption (V·O₂) and cardiac output (CO) during both mild and intense exercise. Patients with heart failure were divided into 2 groups; group L (n=8) consists of patients with low anaerobic threshold (AT) <13 ml/min per kg and group H (n=7) consisting of patients with AT >13 ml/min per kg. At rest, V·O₂ was similar between groups L and H, whereas CO was lower in group L than in group H (3.5+0.3 vs 4.8+1.4 ml/min, p<0.01). Increase in V·O₂ during warm-up exercise was not significant between the 2 groups (7.40.5 (group L) vs 6.20.3 ml/min per kg (group H), ns), but increase in CO was lower in group L than in group H (2.50.6 vs 3.40.4 ml/min, p<0.01). After warm-up to the AT point, however, the increase in not only V·O₂ but also CO was markedly reduced in group L than in group H (V·O₂: 0.50.4 vs 3.70.8 ml/min per kg, p<0.01, CO: 0.20.3 vs 1.10.3 L/min, p<0.01). Based on these measurements, we calculated the arteriovenous oxygen difference (c(A-V)O ₂ difference) during exercise in individual patients using Fick's equation. The c(A-V)O₂ difference was markedly increased in severe heart failure during the warm-up stage, but between the end of warm-up and the AT point, it remained at the same level as that of group H. These results suggest the presence of a unique mechanism regulating the c(A-V)O₂ difference in severe heart failure patients, activation of which may, at least during mild exercise, contribute to efficient oxygen delivery to the peripheral tissues thus compensating for the jeopardized exercise tolerance in those patients. (Jpn Circ J 1998; 62: 741 - 744)

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Ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) has been reported to be induced by exercise or isoproterenol and is considered to be related to catecholamines. This study was designed to examine the role of autonomic tone in spontaneous episodes of VT originating from RVOT. High frequency (HF; peak power of 0.20 - 0.40 Hz) and low frequency (LF; peak power of 0.05 - 0.15 Hz) spectral components of heart rate variability were calculated from RR intervals in a 30-min period before 33 episodes of VT during 24-h Holter monitoring in 8 patients. One VT episode was sustained, 20 were incessant and 12 were nonsustained. The ratio of LF and HF power and heart rate increased significantly from 8 min before the onset of VT, whereas the HF power gradually decreased but this decrease did not reach the statistical significance. In conclusion, an increase of the ratio of LF and HF power preceding VT suggests that activation of sympathetic tone plays an important role in the occurrence of VT originating from the RVOT. (Jpn Circ J 1998; 62: 745 - 749)

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Several studies have shown that combining the change in the ST-segment with another exercise variable improves the predictive value of stress testing. However, no method has been able to combine many stress test variables with the ST-segment change simultaneously and help the clinician better predict future cardiac events. Fuzzy Cluster Analysis (FCA) was used to combine 5 stress test variables with ST-segment deviation to classify each of 232 positive outpatient stress tests as mildly, moderately, or severely abnormal. Cardiac events were recorded in these 3 patient groups up to 96 months (mean 65 months) after the stress tests. Coronary angiography was performed on 159 of these patients within 1 month of their stress tests. FCA better separated the 3 event-free survival curves than classifying the stress tests by three ST-segment (0.5-1.5 mm, 2-2.5 mm, >3 mm) groups (p<0.05). At 2 years, 90% of the FCA mild group were compared with 70% for the 0.5-1.5 mm group (p<0.01). Moderate and severe tests by FCA separated patients with an intermediate from those with a poor prognosis while the 2-2.5 mm and 3 mm or more ST-segment curves did not (p<0.05). FCA showed overall better correlation with coronary score (r=0.71) than did the graded ST-segment groups (r=0.48). FCA predicted both mild and high-grade (triple-vessel and left main) coronary disease better than ST-segment alone. Thus FCA better predicts future cardiac events in patients with positive stress tests than the ST-segment alone. This combined with its usefulness in predicting the extent of coronary disease provides the basis of a clinical strategy for managing patients with positive stress tests. (Jpn Circ J 1998; 62: 750 - 754)

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Previous reports have indicated that echocardiography with automatic boundary detection (ABD) is useful for the noninvasive estimation of left ventricular volume. However, few data exist regarding the measurement of left atrial (LA) volume, which also provides pivotal information in the clinical setting. Therefore, the feasibility of LA volume measurement by ABD in comparison with the manual tracing using modified Simpson's method (SM) was evaluated. Fifty-nine patients with coronary artery disease with sinus rhythm were examined. Using ABD, a region of interest was set around the LA border and mitral annulus from an apical four-chamber view. The maximal and minimal LA volume (Vmax and Vmin) were measured from the volume waveform. Using the SM, the maximal and minimal LA volume were measured by the manual tracing on frozen frames at the apical four-chamber view. The ABD displayed a curve of LA volume change that consisted of passive emptying, diastasis, and active emptying phases during the left ventricular diastolic period. Under these conditions, the Vmax and Vmin were 43.7±11.2 ml and 21.1±7.6 ml, respectively, yielding the volume change of 22.6±6.0 ml. By the SM, Vmax and Vmin were 43.1±9.9 ml {r=0.94, p<0.0001, y (ABD) = 0.91x (SM) + 3.6} and 22.0±9.0 ml (r=0.91, p<0.0001, y = 0.94x + 0.7), respectively, and the volume change was 22.8±6.1 ml (r=0.82, p<0.0001, y = 0.84x + 3.8). These results indicate that the ABD from the apical four-chamber approach could provide an accurate estimation of LA volume change, suggesting the potential value of this method in assessing LA function, although some technical difficulties need to be further overcome. (Jpn Circ J 1998; 62: 755 - 759)

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A case of Wolff-Parkinson-White (WPW) syndrome with several interesting electrophysiologic findings is presented. Although manifest preexcitation had not been documented in clinical routine check-ups for the 2 years before the ablation session, an intermittent preexcitation emerged after an initial unsuccessful radiofrequency current delivery directed at the subvalvular mitral annulus 1 cm distal from the subsequent successful ablation site. During intermittent manifestation of preexcitation, the following observations were made: (1) during manifest preexcitation, a possible Kent potential was recorded at the successful ablation site; (2) during non-preexcited impulse propagation, a local slow potential preceding the QRS complex (pre-QRS potential) was clearly observed at the same site; (3) the pre-QRS potential disappeared during orthodromic atrioventricular reciprocating tachycardia, spontaneous atrial premature contraction and after the subsequent successful ablation; and (4) when the pre-QRS potential was obvious, a small change in QRS morphology of the body-surface ECG was appreciable, compared with that during beats of negative pre-QRS potential. A comparable preceding component was also detected in a signal-averaged ECG. It is considered that the pre-QRS potential might be related to the anterograde concealed conduction through the accessory pathway. (Jpn Circ J 1998; 62: 760 - 764)

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This study was performed to evaluate whether beta-blocker therapy was effective in patients with nonischemic dilated cardiomyopathy (DCM) and bradyarrhythmias supported by pacemaker implantation. Beta-blocker therapy is useful for some patients with DCM, especially those with rapid heart rate or residual nonfibrotic myocardium in the left ventricle, but no data exist on whether beta-blocker therapy is useful in patients with DCM and bradyarrhythmias. The effectiveness of beta-blocker therapy was prospectively evaluated in patients with DCM and bradyarrhythmias supported by pacemaker implantation and compared with those without these arrhythmias. Beta-blocker therapy was started in 63 patients (45 men, 18 women, aged 11 - 83 years) with DCM, in whom 7 had bradyarrhythmias and 56 did not. These bradyarrhythmias were atrioventricular block, sick sinus syndrome and atrial fibrillation with slow heart rate. Of the 56 patients without bradyarrhythmias, 42 (75%) (group 1) responded to beta-blocker therapy, but 5 of the 7 with bradyarrhythmias (71%) (group 2) also responded. Left ventricular end-diastolic dimension was reduced (6.5±0.6 cm to 5.6±0.5 cm; p < 0.0001 in group 1; 6.6±0.8 cm to 5.5±0.2 cm; p<0.02 in group 2) and left ventricular fractional shortening was improved (13±4% to 27±7%; p < 0.0001 in group 1; 12±4% to 29±10%; p < 0.05, in group 2) to the same degree in both groups. These results indicate that beta-blocker therapy for DCM is effective not only in patients without bradyarrhythmias but also in those with bradyarrhythmias supported with pacemaker implantation. (Jpn Circ J 1998; 62: 765 - 769)

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It is assumed that the low-frequency power (LF) of heart rate variability (HRV) increases with progress of congestive heart failure (CHF), therefore positively correlating with cardiac ¹²³I-metaiodobenzylguanidine (MIBG) washout. It is demonstrated here that HRV, including normalized LF, correlated inversely with MIBG washout and positively with the ratio of heart-to-mediastinum MIBG activity in controls and CHF patients, whereas these correlations were not observed within CHF patients. Thus MIBG washout may increase and HRV including normalized LF may decrease with CHF, although the HRV and MIBG measures may not similarly change in proportion to the severity of the cardiac autonomic dysfunction in CHF. (Jpn Circ J 1998; 62: 770 - 772)

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This study focused on the role of the baroreceptor-mediated control during the compensatory process after acute left ventricular overloading induced by aortic regurgitation (AR). Baroreceptor-heart rate sensitivity was measured using a phenylephrine-induced increase in blood pressure according to the steady state method before, 1 day, 1 week and 4 weeks after production of AR in 7 rabbits, and compared with 6 other rabbits that underwent a sham operation. Blood pressure was monitored noninvasively using Finapres in the unanesthetized state. Four weeks after the procedure, the left ventricular diameters of both end-diastole and end-systole were larger in the rabbits with AR than in the sham-operated rabbits. There was no difference in the left ventricular end-diastolic pressure or cardiac output. Left ventricular weight was higher in the rabbits with AR than in the sham-operated rabbits. Myocardial β-adrenergic receptor density and norepinephrine content were comparable between the two groups. Baroreceptor-heart rate sensitivity significantly decreased 1 week after production of AR, and this alteration in sensitivity was partially restored 4 weeks after production of AR. These findings suggested that the altered baroreceptor-heart rate sensitivity was reversible, relating to the compensatory process after acute left ventricular overloading, and that these changes had some role in its pathophysiology. (Jpn Circ J 1998; 62: 773 - 778)

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Two cases of acute myocardial infarction due to an occlusion of the left main coronary artery (LMCA) are presented. Their cardiogenic shock was successfully treated with percutaneous cardiopulmonary support (PCPS), in addition to reperfusion therapy and an intraaortic balloon pump. The 2 patients were able to be weaned from PCPS and discharged from hospital. It is suggested that the early use of PCPS may be life-saving in patients with myocardial infarction due to the occlusion of the LMCA who have progressed to cardiogenic shock. (Jpn Circ J 1998; 62: 779 - 782)

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A 49-year-old woman presented with bilateral coronary fistulas with multiple sites of drainage. She had been referred to hospital for evaluation of a cardiac murmur, and a coronary arteriogram revealed multiple coronary fistulas. One fistula originated from the proximal part of the left anterior descending coronary artery and connected to the main pulmonary artery. Three coronary artery fistulas arised from a conal branch of the right coronary artery and drained into the main pulmonary artery, the right atrium and the great cardiac vein. This is the first reported case of bilateral coronary fistulas with multiple sites of drainage. (Jpn Circ J 1998; 62: 783 - 784)

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A patient with variant angina showed similar findings on both the rest and matched exercise ²⁰¹Thallium (²⁰¹Tl) myocardial perfusion scintigrams. The 65-year old man was admitted to hospital because of rest angina. His electrocardiogram during the attack disclosed ST segment elevation on inferior leads. However, emergency coronary arteriogram showed no fixed stenosis. Intracoronary injection of acetylcholine induced a spasm on the distal right coronary artery, but not in the left coronary artery. In the rest ²⁰¹Tl study, septal perfusion was low on the early image, although partial redistribution of this site was observed on the delayed image without the appearance of chest pain or electrocardiographic ischemic change. Similary, in the ²⁰¹Tl exercise study undergone 2 weeks later, septal redistribution was diagnosed because the early image had decreased septal perfusion. Both the exercise ¹²³I-metaiodobenzylguanidine study and the rest ¹²³I-betamethyl-p-iodophenyl-pentadecanoic acid study showed inferior abnormalities on the early and delayed images. Although a coronary spasm was not induced in the left anterior descending artery with the acetylcholine test, septal redistribution was observed on the delayed image of both the rest and exercise ²⁰¹Tl studies. The mechanism of the redistribution on the rest ²⁰¹Tl study was unclear. (Jpn Circ J 1998; 62: 785 - 787)

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A family with sick sinus syndrome is presented: a mother and her 2 daughters affected with sinus node dysfunction. Electrophysiological studies revealed abnormal atrioventricular conduction in the 2 daughters. All 3 individuals were implanted with a permanent pacemaker to relieve their symptoms. Endomyocardial biopsy from the right ventricle of one daughter showed disarrangement, degeneration, myocyte necrosis and interstitial fibrosis suggestive of myocardial disease. (Jpn Circ J 1998; 62: 788 - 790)

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A 15-year-old female with Ebstein's anomaly was referred to hospital for radiofrequency (RF) current catheter ablation of her refractory paroxysmal supraventricular tachycardia (PSVT) after tricuspid valve replacement. A surface ECG showed ventricular preexcitation of type B Wolff-Parkinson-White (WPW) syndrome. In a baseline electrophysiological study, two types of PSVT with left and right bundle branch block (LBBB and RBBB) configurations were induced. The LBBB type was antidromic and the RBBB type was orthodromic atrioventricular reciprocating tachycardia (AVRT) with a right posterolateral accessory pathway. RF current was successfully delivered at the posterolateral site above the prosthetic valve (V-delta interval = -30 msec). The patient has been free from arrhythmias during a follow-up period of 9 months. RF current ablation seems to be useful for AVRT patients with corrected Ebstein's anomaly. (Jpn Circ J 1998; 62: 791 - 793)

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