There has been increased interest in the beneficial effects of atrio-ventricular (AV) pacing over ventricular (V) pacing. This study attempted to evaluate the changes in cardiac output and left ventricular filling dynamics when the pacing mode was switched from V pacing to AV pacing. Study population consisted of 26 patients with multiprogrammable AV pacemakers. Cardiac output was determined as a product of echocardiographically determined cross sectional area of the aortic annulus and Doppler-determined velocity integral of left ventricular outflow over systole. Left ventricular peak rapid filling rate (PFR) and peak atrial filling velocity to peak rapid filling velocity ratio (A/R) were determined from measurements at the mitral annulus. Cardiac output showed a significant improvement when the pacing mode was switched from V to AV pacing, and the percent change ranged from 3 to 73% (average 26%). The improvement in cardiac output brought about by AV synchrony was greater in patients with smaller PFR (r = -0.71, p < 0.01) and larger A/R ratio (r= 0.77, p < 0.01). On the other hand, PFR was greater with V pacing than with AV pacing. Greater increment of the PFR was produced by the loss of atrial contraction in patients with smaller PFR (r= -0.82, p < 0.01) and larger A/R ratio (r=0.76, p < 0.01). Thus, AV pacing provides a great improvement in left ventricular filling, i. e., cardiac output, which cannot be obtained with V pacing even with the compensatory enhancement of left ventricular rapid filling. These beneficial effects of AV pacing seemed to be greater in patients with impaired left ventricular rapid filling.

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For statistical analysis of 24-hour recordings of arterial pressure (AP) and heart rate (HR), it is necessary to establish a theoretical probability density function of the distributions. In the present study, 24-hour recordings of direct AP and HR were performed in 15 normotensives (NT) and 39 patients with essential hypertension (EH) by means of a new portable device with a digital memory for analyzing frequency histograms. In both NT and EH, frequency histograms of AP(systolic and diastolic AP) and HR during a 24-hour period showed bi-modal curves, whereas those made during sleep and waking produced asymmetrical patterns resembling Gamma distribution. From the AP and HR histograms made fro each subject during sleep and waking, such parameters as mean (M), standard deviation, mode(Mo), skewness (Sk), kurtosis (K) and minimum values (Mi) were calculated. The Sk and M minus Mo were positive, and K was greater than 3 in both HR and AP histograms ; the AP and HR histograms during sleep can be more correctly analyzed with Gamma distribution (mean parameter errors were less than 7.3%) than with Gaussian distribution (in this : S=0, M minus Mo=0, K=3). The Mi would accord with the location parameter of the Gamma distribution.

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We aimed to study 1) the agreement of estimates of the pulmonary blood volume by the double indicator dilution method and the direct destructive method and 2) the fluid volume balance between the pulmonary intravascular and extravascular spaces. We employed the double indicator dilution method using heat and indocyanine green, with a single injection (into the right atrium) and double sampling technique, that is from the pulmonary artery trunk (PAT) and the aortic root (Ao). With this method, we simultaneously determined the pulmonary extravascular water volume (PEWV), defined as the extravascular lung thermal volume estimated in Ao (LTV_Ao), and the pulmonary blood volume (PBV) from PAT to the left atrium (LA) (PBV _PAT-LA). Dogs were divided into groups : a group without intervention (n=16), a group loaded with dextran (n=12) and a group loaded with alloxan (n=7). 1) When all groups were included, PBV _PAT-LA (ml/kg) =1.02 × PBV_direct(g/kg) + 0.96, n=35, r=0.83 where PBV_direct means the blood contents from the pulmonary artery bifurcation to the pulmonary vein measured by the direct destructive method. We substantiated the validity of the use of the double indicator dilution method. 2) In studying the fluid volume balance, based on the results of the direct destructive method, the pulmonary intravascular-extravascular fluid volume ratio (intra/extra) was 1.3 ± 0.3 (mean ± SD) in the control state, implying that the interstitium in the lung is relatively "dry". As overt pulmonary edema developed by dextran infusion, the ratio exponentially decreased to 1.0 ± 0.1 (p < 0.01). The behavior of the fluid volume balance in question (intra/extra), studied with the double indicator dilution method, was essentially similar to that analyzed by the direct destructive method.

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We investigated the morphologic changes in the sarcoplasmic reticulum (SR) in acute myocardial ischemia, induced by occlusion of the coronary artery in the canine heart, by freeze-fracture of SR in situ and in vitro, and they were compared to the alterations in Ca⁺⁺-stimulated ATPase activity and protein composition of the isolated SR. Both SR in situ and the isolated SR exhibited typical intramembranous particles with diameters of 70 to 90 Å in freeze-fracture replicas. The intramembranous particle density of the P face in SR in situ was 3, 319 ± 75 (mean ± SE) per μm² and that in the isolated SR was 2, 667 ± 60 ; particles were more numerous on the concave (P) face than on the convex (E) face. In ischemia for 30 to 60 min a significant decrease in the number of particles was found in SR in situ, and the corresponding change was noted in the isolated SR. Simultaneous decreases in Ca⁺⁺-stimulated ATPase activity and the major ATPase protein of the SR were recognized. The close correlation of the changing pattern between the reduction in Ca⁺⁺-ports the suggestion that a large part of the intramembranous particles represent ATPase protein itself. Decrease in the SR membrane particles strongly suggests the degradation of ATPase protein in the process of ischemic myocardial injury.

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We reported the case of a 46-year-old man with thymolipoma whose chest X-ray initially suggested cardiomegaly. Computed tomography (CT) clearly demonstrated the existence of a large mass adjoining the left ventricular wall in the mediastinum. CT also allowed estimation of the character of the mass including its size, extent, and consistency. At thoracotomy, the tumor was excised and thymolipoma was diagnosed histopathologically.

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late results were studied in 63 patients who underwent complete repair of tetralogy of Fallot. Mild pulmonary stenosis (PS) was present in 73%, moderate PS in 17% and severe PS in 10 of the patients. When a transannular patch was used, wider enlargement of the pulmonary annulus did not always relate to a decrease in right ventricular pressure and right ventricular to pulmonary artery pressure gradient in the late postoperative period. Pulmonary regurgitation (PR) of grade 2 or less did not relate to the late postoperative hemodynamics and cardiac function. PR of grade 3 or over led to right ventricular and pulmonary artery hypertension, and to increases in right ventricular end-diastolic volume and CTR. PR of grade 4 impaired left ventricular function. PR of grade 3 or over with moderate PS led to elevation in right ventricular end-diastolic pressure. In patients with mild PS and PR of grade 2 or less, late postoperative hemodynamics and cardiac function were excellent. To maintain excellet postoperative hemodynamics and cardiac function, it is imperative to obtain PR of grade 2 or less and to use a procedure which will lead to excellent development of the pulmonary annulus. In conventional procedures using a transannular patch, a CSAI of less than 2.5 cm²/m² and precise coaptation between the original pulmonary cusp and the cusp mounted on the patch will aid in avoiding significant PR.

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The importance of conduction disturbances and tachyarrhythmias as the determining factors of the late results of postoperative patients with ventricular septal defect and tetralogy of Fallot was reconfirmed in this follow-up study. It was found, however, that the incidences of complete heart block, bilateral bundle-branch block, and ventricular tachyarrhythimia have decreased significantly since the establishment of cold cardioplegia. This has certainly contributed to the remarkable improvement in late follow-up results of postoperative patients with ventricular septal defect or tetralogy of Fallot.

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From 1965 to 1984, 279 patients with tetralogy of Fallot underwent corrective surgery at Niigata University Hospital, and 228 patients were closely followed postoperatively. Late deaths occurred in 12 cases (5.3%), and overall event-free rate at 20 years postoperatively was 76.9%. The most common events were heart failure due to residual cardiac anomaly and symptomatic ventricular arrhythmias. Treadmill test by Ellestad protocol was performed on 74 postoperative patients, 49% of whom could not complete the protocol. These patients had higher RVEDP and lower PVEF than completing patients. Holter ECG was done on 48 long-term postoperative patients, 48% or whom showed complex ventricular arrhythmias. The age at operation was older and postoperative elapsed time was longer in patients with complex ventricular arrhythmias. Although most postoperative TF patients are able to enjoy a normal social life, the treadmill test and Holter ECG revealed that many patients had latent RV dysfunction and complex ventricular arrhythmias with or without significant symptoms. Since the number of symptomatic patients increases after 15 years postoperatively, a regular check-up with cautious observation is important for the patients' care.

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We studied hemodynamic response to exercise in eight patients who had undergone Rastelli operation 2 to 6 years before this study. Endurance time for the treadmill test was below the low limit of two standard deviations of our normal value in 5 out of 7 patients. On bicycle ergometer exercise test during catheterization, cardiac output increased from 3.8 ± 0.96 liter/min/m² to 6.5 ± 1.7 liter/min/m² when heart rate increased 81 ± 10 to 123 ± 17, the latter reaching 71% of the maximum value. Right ventricular pressure increased from 85 ± 38 mmHg to 114 ± 45 mmHg, along with elevation of the enddiastolic pressure (+5 ± 4 mmHg). Right-sided ventricular ejection fraction increased in 3 out of 6 patients, while left-sided ventricular ejection fraction increased in 4 out of 7 patients. Thus, ventricular pump function does not respond normally to physical activity in many patients after Rastelli operation.

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Twenty-one patients with tetralogy of Fallot following intracardiac repair underwent a treadmill test for evaluation of their exercise capacity. They were divided into two groups according to their post-operative hemodynamic status, the good results group and the poor result group. The maximum oxygen consumption during exercise was significantly decreased in the poor result group, but that of the good result group showed no significant difference from the control group. However, the maximum heart rate in both the good and the poor result groups was significantly lower than that of the control group. Thus, the exercise tolerance in post-operative tetralogy patients was found to be within the normal range as long as their hemodynamic operative result was satisfactory, but the limited capability of increasing heart rate with exercise could present a potential problem in the long-term prognosis.

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This study aims to evaluate the different surgical procedures used in 358 patients undergoing mitral commissurotomy. 89 patients underwent closed mitral commissurotomy by finger fracture (CMCF) and 162 by transventricular dilator (CMCD). 107 patients underwent open mitral commissurotomy (OMC). The following conclusions can be made : 1) Commissurotomy is one of the better palliative procedures for mitral stenosis (MS). 2) It is logical to continue the use of CMCD for selected patients with MS. 3) A careful follow-up study of patients with mitral commissurotomy is necessary, and reoperation should be carried out positively when indicated. 4) It has been confirmed in the survey that 7 patients out of 358 succumbed to sudden death. It is one of the goals of future work to determine the causes of sudden death and to develop an effective method of prevention. 5) It can be expected that a patient with MS who undergoes a flawless operation at the right time will survive and recover full strength.

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Marked improvements have been achieved in the results of valve replacement due to recent developments in cardiac valve prostheses, surgical procedures, myocardial protection methods, and supportive techniques. Since 1974, the aortic valve has been replaced with mechanical valves and the mitral valve with biological valves at our institution. During a cumulative follow-up of 1024 patient-years after 306 valve replacements (126 AVR, 148 MVR and 32 AVR + MVR), the 10-year survival rates were 88% for AVR, 72.6% for MVR and 77.5% for AVR+MVR. The cardiac function of 90% of the survivors was evaluated as Class I or II according to NYHA Functional Classification. As for valve-related postoperative complications, thromboembolism was observed in 2.3%/pt-yr, hemorrhage in 5%/pt-yr, prosthetic valve endocarditis in 1.3%/pt-yr, perivalvular regurgitation in 1.3%/pt-yr and valve malfunction in 1.1%/pt-yr. Of the causes of late deaths, 62.5% were related to valve complications. Re-replacement of the prosthesis was necessary in 17 patients due to valve-related complications, and early death occurred in 1 (5.9%) of these 17. While cardiac valve replacement contributes to improvements in the quality of the patients' long-term postoperative life, currently employed artificial valves are still not ideal with regard to their materials and design, and re-replacement may become necessary in the late postoperative period. Therefore, in addition to selection of the appropriate valve prosthesis for different disorders and optimal prevention of valve-related complications, early diagnosis by non-invasive techniques and early treatment of these complications if they have occurred are of particular importance for the long-term management of patients following cardiac valve replacement.

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Reoperation is one of the most seriously problematical events in postoperative follow-up of patients undergoing open mitral commissurotomy (OMC) for mitral stenosis. In 217 patients with pure mitral stenosis, even when associated with severe subvalvular changes, the actuarial rate of freedom from reoperation was 94% 12 years after OMC. In contrast, in 85 patients with MS combined with regurgitation, the rate was 66%. In postoperative management of patients undergoing OMC, it is mandatory to know preoperative anatomical findings of the stenosed mitral valve.

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To reveal the process of primary failure of the Hancock porcine bioprosthetic heart valve, a real-time two-dimensional echocardiography was undertaken. there were 75 cases (84 valves) with 26 in the aortic valve position, 39 in the mitral valve position, 9 in both the aortic and mitral valve positions, and 1 in the tricuspid valve position. The subjects comprised 35 males and 40 females, whose ages ranged from 18 to 65 years with a mean of 44.7 years. Valvular changes such as thickened valve cusps or abnormal valve movement were observed in 27 (32%) of the 84 valves ; more specifically, in 5 (14.3%) of the 35 aortic valves and in 22 (45.8%) of the 48 mitral valves, indicating that valvular changes occurred most frequently in the mitral valve position (p < 0.01). In the period changes, no significant difference was noted between aortic and mitral valve bioprostheses. The duration ranged from 14.5 to 74.5 months with a mean of 50.2 months. Valvular changes were evident in more than 50% of the valve bioprostheses implanted 6 or more years ago. In the mitral valve position, valve cusp changes appeared more frequently at the anterior cusp than at the inner and outer cusps. The frequency was 17 cases at the anterior cusp, 6 at the inner and 9 at the outer. In 7 of the 11 cases followed up after the appearance of valvular changes, an increase in the changes was recognized 7.5 to 29.5 months (a mean of 16.4 months) later. Thus, chronological observation by real-time two dimensional echocardiography is useful in understanding thickening and abnormal movements, suggesting valve dysfunction of the Hancock porcine bioprosthesis.

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When the incidence of thromboembolism (TE) as a complication was investigated in 171 patients with prosthetic heart valves using pyrolytic carbon, 10 cases were identified i a mean follow-up period of 2.43 years. Of these 10, two patients had died. The incidence of TE as a percentage per patient- year was 2.41 on the whole, 2.15 in patients with aortic valve replacement (AVR), 2.48 in patients with mitral valve replacement (MVR) and 2.52 in patients with double valve replacement (DVR). It is evident that TE is still an important complication following prosthetic heart valve surgery and the patient's return to society. TE tended to occur somewhat more often in cases of MVR and DVR than in those of AVR. TE was apt to appear early in the postoperative period, often within a year, and was often seen in the brain. To prevent TE, it is necessary to carefully control blood coagulation by the administration of anticoagulants.

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Between 1970 and 1985, 221 patients with coronary artery occlusive disease underwent aorto-coronary bypass (A-C bypass) and other procedures. Among these patients, 187 had A-C bypass alone and A-C bypass in addition to correction of valvular lesions or arterialization of the coronary vein, myocardial puncture by laser. The remaining 34 had surgical corrections for myocardial infarction and its complications. Subjects were 100 patients who underwent A-C bypass alone over 6 months ago and whose follow-up study could be performd. Subsequently, 94% of the patients have met the criteria for grade I of NYHA functional capacity and have returned to normal work at a mean of 4 years and 2 months after surgery. Improved left ventricular function has been maintained postoperatively in the patients with complete revascularization. Improved operative technique, in addition to intraoperative balloon angioplasty and onlay patch grafting, have increased the patency rate (78% in 1 mm, 94% in 2 mm of coronary diameter) of the grafts with postoperative anticoagulant therapy. on the basis of our long-term observations, coronary bypass surgery, particulary in complete revascularization, provides for significant improvement in both the quality and life expectancy of patients with severe coronary heart disease. Treadmill exercise test and magnetic resonance image (MRI) were useful, non-invasive and acceptable examinations in long-term follow up.

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We studied 272 patients undergoing coronary artery bypass surgery (CABS) to clarify the long-term effects of CABS and to identify problems in long term management. Data on patients' pre and postoperative medical status were obtained from hospital files. A specially designed questionnaire was sent to all patients to assess residual angina, return to work, non-work physical activity and improvement in the quality of life after a mean follow-up of 29 months. Multivessel disease accounted for 89% of all patients and complete revascularization was achieved in 55%. A total of 131 events of complications associated with CABS occurred in 112 patients ; post-transfusion hepatitis was the most frequent complication (26%). Graft patency rate was 89% at the time of hospital discharge. Bypass grafts were patent in 95% of 243 grafts which were restudied at a mean period of 19 months after the first study. There was no significant difference in the patency rate between patients with well controlled, poorly controlled or discontinued anticoagulant therapy. Patients who were relieved from angina, returned to gainful work and had no limitation in non-work physical activity accounted for 74%, 79% and 73%, respectively. By subjective assessment, the quality of life improved in 76% of all patients. Objectively, contributing factors preventing improvement in the life quality were residual angina and post-transfusion hepatitis. There were 13 patients who were readmitted because of cardiac events. Three patients died from these events including two from sudden death during follow-up. We conclude that the beneficial effects of CABS are actually attainable. New approaches shoud be considered for increasing graft patency rate to an angina-producing artery and in preventing post-transfusion hepatitis. In this study, the benefits of the long-term use of anticoagulant therapy is questionable.

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Postoperative clinical findings from 25 patients with surgical A-V block and 12 with SSS following surgery for ASD who received permanent pacemakers were analyzed in order to consider the long-term management of postoperative bradyarrhythmias. (1) Surgical A-V block : Episodes of Adams-Stokes were observed in 11/25 patients before pacemaker implantation, and in 6 of these (55%) the onset of episodes occurred more than a year after open heart surgery. Of 8 cases for which ECG's during Adams-Stokes were available, 2 had bifascicular or trifascicular block which progressed to complete A-V block below the His bundle. The 6 others (75%) had ventricular tachycardia or ventricular flutter-fibrillation during Adams-Stokes. 2 of these had blocks above the His bundle. 4/25 had improvement of complete A-V block within a month. Following pacemaker implantation, 3 died of heart failure and 3 of sudden death. 5 year survival was 70%. Therefore, surgical A-V block requires careful long-term management, and the presence of ventricular tachyarrhythmias as well as the location of block are important predictors of patient risk. (2) SSS after surgery for ASD : 10/12 patients had Adams-Stokes, of which 6 (60%) had initial onset over 5 years after surgery, and 9 had paroxysmal atrial flutter and fibrillation which coincided with the onset of Adams-Stokes. 3 of 7 patients (42%) for whom preoperative ECG's were available had sinus bradycardia. Thus, SSS after ASD surgery maybe preceded by preoperative deterioration of sinus node function and succeeded by late onset of Adams-Stokes, necessitating pre- and postoperative assessment of sinus node function. The presence of atrial tachyarrhythmias also serves as an important indicator of the severity of SSS after ASD surgery. The onset of Adams-Stokes varied by patient over a wide range of time, emphasizing the need for careful long-term follow-up. Clinical symptoms and prognosis were affected by tachyarrhythmias as well as the severity of the bradycardia. Therefore, the presence of ventricular/atrial tachyarrhythmias is an important factor in the long-term management of postoperative bradyarrhythmias.

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For young female patients with cardiac diseases, to be married, pregnancy and delivery are serious problems. Ninety-two post-operative patients (138 deliveries) and 57 non-surgical patients (86 deliveries) were subjected to analysis of their cardiac and obstetric conditions. A stable course and successful delivery were observed in the patients treated whose cardiac diseases were treated with surgical therapy. Among the non-surgical patients, however, impairment of their clinical condition was experienced including 3 maternal deaths. Incidence of various complications occurring during the course of pregnancy and delivery was 12.3% in the surgical and 18.6% in the non-surgical groups. It was clinically demonstrated that women suffering from cardiac diseases might well tolerate their pregnancy and delivery if accorded proper surgical treatment.

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