Randomized clinical trials have demonstrated that coronary stenting is more successful than balloon angioplasty in improving short- and long-term outcomes. However, it remains unknown whether those results can be generalized to broad-based practice. This study aimed to determine whether the outcome for patients with acute myocardial infarction (AMI) undergoing coronary stent placement would be better than those undergoing balloon angioplasty. The risk-adjusted mortality and subsequent revascularization rates were compared for 2,185 patients from a nationwide Japanese registry during 1997. A total of 1,349 patients were treated with balloon angioplasty alone and 836 had stent placement. There were no statistically significant differences in the prevalence of demographic, clinical, and angiographic variables, except that the angioplasty group had a greater proportion of female patients and those with a left circumflex lesion. Unadjusted in-hospital mortality was comparable (7.6 vs 6.3%; p=0.28), despite higher angiographic success rate for the stent group (89.7 vs 97.7%; p<0.01). Adjusted odds ratio for in-hospital mortality was 0.75 (p=0.19). The same-admission bypass surgery rate was also similar. The 1.9-year post-discharge mortality rate was similar. The need for subsequent revascularization procedures was also similar, but restenosis was significantly lower in the stent group (34 vs 45%; p<0.01). The superiority of clinical outcome for stenting rather than balloon angioplasty could not be demonstrated in broad-based registry patients, despite technically successful results. (Circ J 2003; 67: 369 - 374)

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Earlier studies have shown that administration of beraprost sodium (BPS), an orally active prostacyclin analogue, improves hemodynamics in patients with primary pulmonary hypertension (PH), but it is not known whether BPS has beneficial effects in secondary precapillary PH. The present study investigated the hemodynamic and hormonal parameters of 18 patients with secondary precapillary PH (8 patients with chronic thromboembolic PH, 7 with collagen vascular disease, and 3 with residual PH after surgery for atrial septal defect). Hemodynamics were repeatedly measured by right heart catheterization. Treatment with BPS improved New York Heart Association (NYHA) functional class in 10 of the 18 patients and significantly decreased pulmonary vascular resistance by 17% (12.9±1.1 to 10.7±1.2 Wood units, p<0.01). Circulating brain natriuretic peptide and uric acid significantly decreased from 246±61 to 215±65 pg/ml and from 6.5±0.6 to 5.3±0.3 mg/dl, respectively. In summary, BPS therapy improved NYHA functional class, hemodynamics, and hormonal parameters in patients with secondary precapillary PH. Thus, oral administration of BPS may be a new therapeutic strategy for the treatment of secondary precapillary PH. (Circ J 2003; 67: 375 - 378)

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Angiotensin-converting enzyme (ACE) inhibitors have cardioprotective effects in animals, but whether that occurs in humans is still controversial. The effect of myocardial ACE activity on coronary vascular resistance during coronary artery bypass surgery and on serum brain natriuretic peptide (BNP) concentration after surgery was studied in myocardial tissue sampled from the right atrium of patients during cardiac surgery (n=20). Tissue enzyme activity (nmol/min per mg protein) was measured using a photometric technique, and the flow rate and pressure upon antegrade infusion of a crystalloid cardioplegic solution was measured for calculating the coronary vascular resistance (mmHg · ml^-1 · min^-1). Serum BNP concentration (pg/ml) was measured on days 0 and 5 after the surgery. Linear regression between tissue ACE activity and coronary vascular resistance (y = 0.46x + 0.56, r=0.85) as well as serum BNP concentration on days 0 (y = 129x + 30, r=0.59) and 5 (y = 347x + 180, r=0.73) after the surgery was significant (x: ACE activity; y: coronary vascular resistance/serum BNP concentration). The results indicate that inhibition of myocardial ACE activity might improve coronary circulation during surgery and hence, cardiac function after surgery. (Circ J 2003; 67: 379 - 383)

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The effect of torasemide and furosemide therapy was compared in 50 patients who had chronic heart failure and symptoms [NYHA class II-III] despite long-term therapy with both low-dose furosemide and angiotensin-converting enzyme inhibitors. In this randomized 6-month, open-label trial, baseline and follow-up echocardiograms and neurohumoral assays were obtained in 25 group F patients (continued same dose of oral furosemide at 20-40 mg/day) and in 25 group T patients (received torasemide at 4-8 mg/day in place of furosemide). At 6 months, parameters were unchanged in group F whereas the group T patients had a lower left ventricular end-diastolic diameter (p<0.005) and left ventricular mass index (p<0.005) with improved Doppler filling parameters, decreased plasma B-type natriuretic concentration (p<0.001) and increased plasma concentrations of active renin (p<0.005) and aldosterone (p<0.001). The magnitude of these changes appeared dose dependent and it is suggested these favorable effects of switching from furosemide to torasemide may be related to aldosterone receptor blockade. (Circ J 2003; 67: 384 - 390)

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The aim of this study was to investigate the mechanism of spontaneous termination of atrial fibrillation (AF) by comparing it with drug-induced termination on the basis of changes in fibrillation cycle length (FCL). Fast Fourier transform analysis was carried out on the electrocardiogram (ECG) records of 27 patients with paroxysmal AF without organic heart disease. In 8 patients with drug-induced termination of AF, spectral analysis of the data from surface ECG lead V1 was performed before and after class I antiarrhythmic drug infusion for 10 min. In 19 patients with spontaneous termination of AF, the analysis used the Holter ECG recordings at 10 min before the spontaneous termination and at the termination. FCL was calculated from the peak frequency of each epoch and the mean FCL and the coefficient of variation (CV) of FCL were determined from the data of 20 epochs. In the 8 episodes of drug-induced AF termination, the mean FCL increased significantly with class I drugs (from 151±17 to 203±21 ms, p<0.001), whereas in the 19 episodes of spontaneous termination, the mean FCL and CV of FCL at termination did not differ from those at 10 min before the termination. Of the 19 episodes, 10 episodes terminating in the morning showed a significant increase in the FCL of the last epoch of the termination period (from 158 ±22 to 172±17 ms, p<0.05). In the 9 episodes terminating in either the afternoon or the evening, the FCL of the last epoch did not change significantly. Although drug-induced termination of paroxysmal AF may depend on a gradual increase in FCL, the pattern of spontaneous termination may depend on the time of day. Spontaneous termination in the morning may be caused by an abrupt increase in FCL related to vagolytic autonomic balance. (Circ J 2003; 67: 391 - 395)

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The present study examined the influence of the extent of the ischemic area on right ventricular (RV) systolic function and the relation between the RV global and regional systolic function in patients with anteroseptal myocardial infarction (MI). Biplane right ventriculography was performed in 15 subjects as the control group, and 46 patients with anteroseptal MI as the MI group. Three dimensions of the RV (the long axis dimension [LA], the anterior-posterior dimension [AP] and the septum-free wall dimension [SF]) were examined to assess regional function The MI group had a larger right ventricular end-systolic volume index and lower right ventricular ejection fraction than the control group. The more proximal the coronary lesion, the lower was the ejection fraction of the RV in the MI group. The MI group had lower percent shortening (%shortening) of the SF than the control group, but there were no significant change in the %shortening of AP and LA between the groups. The results suggest that the degree of impairment of RV systolic function depends on the extent of the infarcted area, and that the impairment is mainly from a reduction in the %shortening of the SF. (Circ J 2003; 67: 396 - 400)

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The present study was designed to investigate the accuracy of multislice spiral computed tomography (MSCT) in detecting coronary artery disease, compared with coronary angiography (CAG), using a new retrospectively ECG-gated reconstruction method that reduced cardiac motion artifact. The study group comprised 54 consecutive patients undergoing MSCT and CAG. MSCT was performed using a SOMATOM Volume Zoom (4-detector-row, Siemens, Germany) with slice thickness 1.0 mm, pitch 1.5 (table feed: 1.5 mm per rotation) and gantry rotation time 500 ms. Metoprolol (20-60 mg) was administered orally prior to MSCT imaging. ECG-gated image reconstruction was performed with the reconstruction window (250 ms) positioned immediately before atrial contraction in order to reduce the cardiac motion artifact caused by the abrupt diastolic ventricular movement occurring during the rapid filling and atrial contraction periods. Following inspection of the volume rendering images, multiplanar reconstruction images and axial images of the left main coronary artery (LMCA), left anterior descending artery (LAD), left circumflex artery (LCx) and right coronary artery (RCA) were obtained and evaluated for luminal narrowing. The results were compared with those obtained by CAG. Of 216 coronary arteries, 206 (95.4%) were assessable; 10 arteries were excluded from the analysis because of severe calcification (n=4), stents (n=3) or insufficient contrast enhancement (n=3). The sensitivity to detect coronary stenoses ≥50% was 93.5% and the specificity to define luminal narrowing <50% was 97.2%. The positive predictive value and the negative predictive value were 93.5% and 97.2%, respectively. The sensitivity was still satisfactory (80.6%) even when non-assessable arteries were included in the analysis. The new retrospectively ECG-gated reconstruction method for MSCT has excellent diagnostic accuracy in detecting significant coronary artery stenoses. (Circ J 2003; 67: 401 - 405)

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Experimental studies have postulated the ischemic cascade and the present study was designed to elucidate whether it can be observed in the clinical setting. Fifty-three patients suspected of having coronary artery disease were studied. Myocardial perfusion abnormalities (MPA) and wall motion abnormalities (WMA) were assessed simultaneously by infusion of Levovist during dobutamine stress echocardiography. Time - intensity data of myocardial opacification were fitted for Y=A (1-e^{-β t}) from which the rate of increase (β) of intensity were derived both at rest and during stress. Wall motion was also given a score. Bright opacification was observed in 50 patients: 25 showed significant stenosis (>50%) in the left anterior descending artery (group II) on coronary angiography and 25 did not (group I). Significant differences were found in the β ratio (stress/rest) between the 2 groups at a low-dose (2.0±0.3 vs 1.5±0.5, p<0.05) and at a high-dose of dobutamine (2.7±1.0 vs 1.1±0.5, p<0.001), whereas the wall motion score differed only at a high-dose. Of the 25 patients in group II, MPA preceded WMA in 12, both occurred at the same stage in 12, and neither MPA nor WMA was seen in 1. These data prove the ischemic cascade clinically, using contrast echocardiography, by demonstrating that MPA precede WMA during dobutamine stress in patients with coronary stenosis. (Circ J 2003; 67: 406 - 410)

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The purpose of this study was to determine the rate of participation of patients after acute myocardial infarction (AMI) in phase II cardiac rehabilitation with exercise training (ie, exercise cardiac rehabilitation, ECR) in Japan. Forty-six hospitals treating patients with AMI were surveyed for their implementation of phase II ECR after AMI in 1996-98. Of the 46 hospitals, 19 were approved and 27 were not approved for health insurance payment for ECR. A total of 13,685 patients with AMI were admitted to the 46 hospitals. There were no differences between approved and non-approved hospitals in the annual number of patients with AMI (Approved, 117+61 vs Non-approved, 86+71 patients per hospital, NS), the rate of performance of emergency coronary angioplasty (63+16 vs 65+20%, NS), or the rate of emergency coronary stenting (31+16 vs 34+22%, NS). However, ECR was performed routinely in 84.2% (16/19 hospitals) of the approved hospitals, but in only 22.2% (6/27 hospitals) of the non-approved hospitals (p<0.001). Although the participation rate of AMI patients in ECR was 21.0% (2,875/13,685 patients) overall, it was markedly lower in the non-approved hospitals (8.0%, 557/6,999 patients) than in the approved hospitals (34.7%, 2,318/6,686 patients, p<0.0001). Based on the present result, the overall rate of participation of AMI patients in ECR in Japan was estimated at 4.8-11.7%. Despite similar patient volumes and acute phase interventional treatment of AMI between the hospitals approved and not approved for health insurance payment for ECR, ECR was markedly underused in the non-approved hospitals in Japan. To promote ECR for all AMI patients in Japan, the number of hospitals approved for ECR should be substantially increased. (Circ J 2003; 67: 411 - 415)

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The myocardial velocity profile (MVP) and gradient (MVG) between the endocardium and epicardium of the left ventricular (LV) wall measured by color-coded tissue Doppler imaging (TDI) are new indices for evaluating regional LV myocardial function. However, accurate recording and measurement of the MVP is difficult using conventional methodology because of the stochastic nature of the ultrasound signal; that is, the effect of speckled noise. The aim of this study was to validate the accuracy and establish the validity of a newly developed method for measuring the MVP and MVG using 10 clinically normal controls and 10 patients with a hypertensive hypertrophied LV posterior wall. A non-isotropic, averaging algorithm was developed that was capable of obtaining a stable MVP (averaged MVP). Averaged MVP was recorded using parasternal, LV short-axis, color-coded TDI, placing regions of interest along the LV posterior wall with the reference point for angle-correction being at the center of LV contraction. The velocity from epicardium to endocardium within the region of interest was automatically angle-corrected to calculate the velocity component radially relative to the LV cavity and was spatially averaged along the circumference within the region of interest. Inter- and intraobserber variabilities of measurements were lower in the averaged MVP and MVG than in the conventional MVP and MVG. The correlation coefficients of the linear regression lines of systolic and early diastolic MVPs in the LV posterior wall were higher in all controls and hypertensive patients with the averaged method than with the conventional TDI procedures. The mean peak systolic and early diastolic MVGs were lower in the hypertensive group than in the controls. In conclusion, the newly developed averaged MVP provides a stable and reproducible index for the quantitative assessment of regional LV myocardial function. (Circ J 2003; 67: 416 - 422)

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Constrictive remodeling occurs in significant atherosclerotic lesions of the diabetic patient, but the impact of diabetes mellitus (DM) on the angiographically normal coronary artery is still unclear. Morphometric analysis using intravascular ultrasound (IVUS) prior to intervention evaluated 54 sites in 33 DM patients and 106 in 62 non-diabetic patients. Vessel area (VA) and lumen area (LA) were measured at angiographically normal sites in the vessel. Plaque area (PA) was calculated as VA - LA. Percentage plaque area (%PA) was calculated as PA VA. Even in the angiographically normal site, mild coronary atherosclerosis was detected by IVUS in both groups. In the patients with DM, VA and LA were significantly smaller than in the non-diabetic patient (15.5 vs 17.8 mm², p<0.01; and 10.1 vs 12.2 mm², p<0.01 respectively), whereas %PA was similar (34.5 vs 31.6%). At angiographically normal sites where mild coronary atherosclerosis is detected by IVUS, the coronary artery of diabetic patients is smaller than that of the non-diabetic. These results suggest impaired compensatory enlargement or some other constrictive mechanism has already occurred in the early stages of coronary atherosclerosis in patients with DM. (Circ J 2003; 67: 423 - 426)

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In patients with Kawasaki disease (KD), serial evaluation of coronary artery aneurysms (CAAs) and luminal narrowing is essential for risk stratification and therapeutic management. Therefore, non-invasive assessment of the status of the coronary artery is of utmost importance in patient management. Multislice spiral computed tomography (MSCT) permits non-invasive visualization of the entire coronary artery system and was used in the evaluation of 4 patients with KD. CAAs and high-grade coronary artery stenoses were detected by MSCT and corroborated the findings of coronary angiograms performed within the previous 2 years. MSCT has the potential to be the standard diagnostic tool in adolescents with KD. (Circ J 2003; 67: 427 - 430)

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The study was designed to characterize patients with chronic heart failure (CHF) in Japan in terms of the etiologies and prognosis. CHF was defined by ejection fraction (EF ≥50%), left ventricular diastolic dimension (LVDD ≥55 mm) or a past history of congestive heart failure. Among the 721 recruited patients, the most frequent etiology for CHF was dilated cardiomyopathy (DCM) in patients aged less than 59 years, and valvular heart disease (VHD) in those aged 70 years or more. The 1-year crude mortality was 8% overall and 12% in patients with myocardial infarction (MI). Sudden death accounted for 40% of the total deaths among all patients, and 60% in patients with MI. Multivariate logistic regression analysis showed that brain natriuretic peptide (BNP) was a consistent prognostic marker in CHF patients with a variety of etiologies. Total death and hospitalization because of heart failure were significantly less frequent in patients with BNP less than 100 pg/ml. In conclusion, the etiologies of Japanese CHF appear to be more diverse than those of other Western countries, but BNP is an excellent prognostic marker despite the etiological diversity. Sudden, unexpected death in CHF patients is also a serious problem in Japan. A nation-wide epidemiologic study should be done to characterize Japanese CHF. (Circ J 2003; 67: 431 - 436)

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The aims of this study were to evaluate the changes in the electrophysiological characteristics of the right atrium after the administration of flecainide and to clarify whether flecainide has a selective effect on human atrial tissue. Electrophysiological measurements were made in 38 patients, before and after intravenous administration of flecainide (2 mg/kg per 10 min). The effective refractory period of the right atrium (ERP-A), maximum conduction delay (Max.CD), repetitive atrial firing zone (RAFZ), fragmented atrial activity zone (FAAZ), and conduction delay zone (CDZ) were studied in the patients who were divided into 2 groups based on whether repetitive atrial firing (RAF) was induced in the baseline study. Flecainide significantly prolonged the ERP-A (202±22 to 238±33 ms, p<0.001) and shortened Max.CD (77±17 to 63±32 ms, p<0.05) in the patients with RAF, but not in those without RAF in the baseline study. After flecainide administration, there were significant reductions in the RAFZ (43±22 to 13±19 ms, p<0.0001), FAAZ (51±22 to 28±26 ms, p<0.001) and CDZ (70±21 to 48±30 ms, p<0.01) in the patients with RAF. However, atrial fibrillation (AF) was induced by stimulation after flecainide in 2 patients without RAF in the baseline study. There was a significant negative correlation between the ERP-A in the baseline study and the change in the ERP-A upon flecainide administration (r=0.45, p<0.01). Flecainide may preferentially activate the substrate for AF and RAF, but that action is mainly based on the electrophysiological characteristics found in the baseline study. (Circ J 2003; 67: 437 - 442)

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To evaluate the effects of synthetic human atrial natriuretic peptide (hANP) on myocardial reperfusion injury and left ventricular remodeling, 19 patients within 12 h of a first attack of anterior myocardial infarction (AMI) underwent intracoronary injection of 25 μg of hANP immediately after coronary angioplasty, combined with intravenous infusion of 0.025 μg · kg^-1 · min^-1 of hANP initiated on admission for 1 week (hANP group); 18 similar patients had saline administered (control group). The incidences of premature ventricular contraction, ventricular tachycardia and/or fibrillation in the hANP group were significantly less than in the control group after coronary angioplasty. Left ventricular ejection fraction was significantly greater and left ventricular end-diastolic volume index was significantly smaller 6 months after coronary angioplasty. Left ventricular regional wall motion of the infarcted segments significantly increased. Thus, hANP remarkably suppressed reperfusion phenomena and preserved left ventricular function through improvement of regional wall motion of the infarcted segments after coronary angioplasty. (Circ J 2003; 67: 443 - 448)

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There are M cells in the canine, rabbit, guinea pig, and human left ventricle (LV), but it is not known if they are present in the feline LV. Arterially perfused feline LV preparations were used for the recording of transmembrane action potentials from the epicardium (Epi), midmyocardium (M) and endomyocardium (Endo) under control conditions (n=12) and in the presence of I_Ks blocker (chromanol 293B: 10 μmol/L, n=6) or I_Kr blocker (E-4031: 2 μmol/L, n=6). The steady-state action potential duration at 90% repolarization and cycle length (APD90/CL) relation was obtained and fitted by the hyperbolic function APD₉₀ = CL/[(a × CL) + b]. In control, the shortest and longest action potential duration (APD) were observed in Epi and M, respectively, and the APD₉₀/CL-relation curve was steeper in the M or Endo than in the Epi. Chromanol 293B prolonged APD in Epi, but not in M or Endo, resulting in no significant difference of the APD₉₀/CL-relation curve among the 3 regions. E-4031 markedly, but homogeneously, prolonged APD in all regions, giving rise to decreased transmural dispersion of repolarization. In conclusion, there exists an M cell layer with a longer APD than the Epi and Endo layers and there is transmural electrical heterogeneity in the feline LV; however, the response to I_Kr blocker is different from that of the canine LV probably because of species differences in the I_Kr and I_Ks. (Circ J 2003; 67: 449 - 454)

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Three-dimensional visualization of cardiac activation has become important for providing further insights into the pathophysiological mechanisms of arrhythmias and to increase the efficacy of catheter ablation. The noncontact mapping system enables a single-beat analysis of the reconstructed geometry of the cardiac chamber. In 8 patients with various kinds of arrhythmias (3 with atrial flutter, 2 with right ventricular outflow tract ventricular tachycardia, 1 with idiopathic left ventricular tachycardia, 1 with atrioventricular nodal reentrant tachycardia and 1 with concealed Wolff-Perkinson-White syndrome), non-contact mapping using an EnSite 3000 system was performed for the guidance of catheter ablation. The optimal sites for successful ablation were detected and all of these arrhythmias were successfully eliminated with the radiofrequency energy applications without any adverse effects. The computerized EnSite 3000 mapping system described here computes accurate isopotential maps that are a useful guide for catheter ablation. (Circ J 2003; 67: 455 - 460)

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Spontaneous nontraumatic rupture of the ascending aorta occurred in a hypertensive patient. The clinical findings suggested acute aortic dissection, and echocardiography showed a large pericardial effusion. Computed tomography scanning did not indicate aortic dissection, but aortography in 3 projections revealed an area of intimal disruption similar to the niche of an ulcer. The patient underwent replacement of the ascending aorta and proximal aortic arch, and the postoperative course was uneventful. (Circ J 2003; 67: 461 - 463)

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Atherosclerotic disease of the coronary artery may simultaneously involve the subclavian artery, and a significant stenosis of the left subclavian artery may result in recurrent myocardial ischemia in patients with patent left internal mammary artery (LIMA) grafts because of `coronary steal' through the LIMA. Isometric exercise of the left arm may improve myocardial perfusion through vertebral - subclavian steal by flow reversal in the ipsilateral vertebral artery because of the change in the pressure gradient between the circle of Willis and the distal subclavian artery. The present patient had coronary steal through a LIMA after coronary artery bypass surgery and a transient vertebral - subclavian steal with improved myocardial perfusion as a result of exercise of the left arm. (Circ J 2003; 67: 464 - 466)

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A 16-year-old female with a family history of coronary artery disease was referred to hospital because of recurrent chest oppression unrelated to exertion. Although a selective coronary angiogram showed no atherosclerotic lesions, coronary spasm was provoked by acetylcholine in the left coronary artery, accompanied by chest pain and depression of blood pressure. This is the youngest healthy young female to be diagnosed with coronary vasospasm by provocation test. Because there are no risk factors, the vasospasm must be related to unknown hereditary factors. (Circ J 2003; 67: 467 - 469)

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A 26-year-old man had been diagnosed with a cardiac murmur from birth. In 1998, he was admitted to hospital because of slight fatigue. A grade 5/6 continuous murmur was audible near the right sternal border at the second intercostal space. Doppler echocardiography detected an abnormal flow that suggested that an aneurysm of the right coronary sinus of Valsalva had ruptured into the right ventricular inflow tract. Blood tests showed a 19% step-up in oxygen saturation value between the right atrium and right ventricle, indicating a ventricular septal defect with left to right shunt. Coronary angiography revealed a single coronary artery. Surgical repair was carried out and the patient made an uneventful recovery. This rare combination of a ruptured aneurysm of the sinus of Valsalva coexisting with a ventricular septal defect and a single coronary artery has not been reported previously. (Circ J 2003; 67: 470 - 472)

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