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From the correlation between the blood flow dynamics and wall dynamics in the left ventriocle (LV) analyzed using echo-dynamography, the ejection mechanisms and role of the intra-ventricular vortex in the LV were elucidated in detail during the pre-ejection transitional period (pre-ETP), the very short period preceding LV ejection. The study included 10 healthy volunteers. Flow structure was analyzed using echo-dynamography, and LV wall dynamics were measured using both high-frame-rate two-dimensional echocardiography and a phase difference tracking method we developed. A large accelerated vortex occurred at the central basal area of the LV during this period. The main flow axis velocity line of the LV showed a linearly increasing pattern. The slope of the velocity pattern reflected the deformity of the flow route induced by LV contraction during the pre-ETP. The centrifugal force of the vortex at its junction with the main outflow created a stepwise increase of about 50% of the ejection velocity. Ejection of blood from the LV was accomplished by the extruding action of the ventricular wall and the centrifugal force of the accelerated vortex during this period. During ejection, acceralated outflow was considered to create a spiral flow in the aorta with help from the spherical structure of the Valsalva sinus.

While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI.

In order to reduce negative effects on the inner surface of radial arteries, together with Fukuda Denshi Co (Japan) we have developed 3 Fr diagnostic catheters the actual outer diameter of which is 3.4 Fr (1.14 mm). In October 2003, we performed the first coronary angiography and left ventriculography using these 3 Fr catheters. Thus far, 3 Fr catheters have been used for more than 8000 patients in our center. In recent years, angiographies have been performed successfully in >96% of patients using 3 Fr catheters. The decreased size of the outer diameter of the catheter brought about innovative changes in coronary diagnosis and therapy, in particular by facilitating the use of trans-radial approaches instead of the trans-femoral approach. Moreover, further reductions in the size of the catheter outer diameter enables us to use the distal radial approach instead of the conventional trans-radial approach. At present, about 80% of coronary angiographies and interventions are performed using the distal radial approach in our center. According to several reports, the inner diameter of the distal radial artery is smaller than the radial artery. Therefore, this 3 Fr diagnostic catheter is useful in cases where the inner diameter of the distal radial artery is not accessible to the bigger 4 Fr catheter. In order to reduce further negative effects on radial arteries, we developed 2.8 Fr diagnostic catheters the actual outer diameter of which is only 0.93 mm (930 μm). In March 2016, we performed the first coronary angiography using these catheters. Moreover, in November 2018, we performed the first coronary angiography using the distal radial approach with these 2.8 Fr catheters. In future, these and further technical innovations resulting in the downsizing of many types of devices used in the coronary and endovascular fields will create new and powerful applications of “Slender”, to make it mean “less invasive”.

Cardiac interventional radiology (IR) can cause radiation injury to the staff who administer it as well as to patients. Although education in the basic principles of radiation is required for nurses, their level of radiation safety knowledge is not known. The present study used a questionnaire protocol to assess the level of radiation safety knowledge among hospital nurses.A questionnaire to assess the level of training and current understanding of radiation safety was administered to 305 nurses in 2008 and again to 359 nurses in 2010. Our study indicates that nurses had insufficient knowledge about radiation safety, and that a high percentage of nurses were concerned about the health hazards of radiation. Moreover, more than 80% of the nurses expressed an interest in attending periodic radiation safety seminars. Annual radiation protection training for hospital staff (including nurses) is important.Our results suggest that nurses do not have sufficient knowledge of radiation safety and should receive appropriate radiation safety training. Many had a minimal understanding of radiation and thus had significant concerns about the safety of working with radiation. Periodic radiation safety education/training for nurses is essential.

Cardiac resynchronization therapy (CRT) often requires a long fluoroscopic time and protection from scatter radiation. This study reports on scatter radiation levels during CRT, with and without additional shielding, and using standard or low pulse rate fluoroscopy. Additional lead-shielding drape (0.35-mm lead equivalent) was used on the left side of the table and pulsed fluoroscopy was performed at rates of 10 pulses/s (usual rate) and 7.5 pulses/s (low pulse rate). Fluoroscopy scatter radiation was measured for both pulse rates using an acrylic phantom with a radiation survey meter, both with and without the additional lead-shielding drape. With the additional lead-shielding drape, the fluoroscopy scatter radiation was reduced by 74.3% at 10 pulses/s and 78.6% at 7.5 pulses/s. If the fluoroscopy was changed from 10 pulses/s to 7.5 pulses/s, the scattered radiation at the primary physician’s position was reduced by 24.0%. The combined use of additional shielding drape and low pulse rate fluoroscopy reduced scatter radiation by over 80%. Additional lead-shielding drape and low pulse rate fluoroscopy are effective in reducing the scattered radiation dose to physicians and nurses during CRT.

Dobutamine and dipyridamole stress echocardiographies are both well able to detect myocardial ischemia resulting from coronary diseases by recognizing the regional wall motion abnormality (WMA). Here we report a method for describing WMA in detail. In pharmacological stress echocardiography, because of difficulties in recognizing the two-dimensional pattern, accuracy sometimes depends upon the skill of the operator. Two stroke volumes obtained using the M-mode and Doppler methods were examined to detect abnormal regional cardiac function by the dipyridamole stress test. Stroke volume obtained by the M-modereflects regional cardiac function and that estimated from the outflow using the Doppler methodreflects total cardiac function. These two stroke volumes were compared in normal subjects and patients with coronary-diseases. The results indicated consistent discrepancies between these two stroke volume in the ischemic hearts as a results of coronary stenosis, whereas changes in stroke volumes in the normal subjects showed the same tendency. This method of combining information about the regional and total functions is thus useful in examining the WMA and regional cardiac function, although it can not be applied to subjects whose stroke volume does not increase under stress.

To investigate the drive condition of the artificial heart from a neurophysiological point of view, the dynamic transduction characteristics of the baroreflex system were analyzed by means of sympathetic neurograms. Two pneumatically actuated ventricular assist devices were implanted as biventricular bypasses (BVBs) in adult mongrel dogs to compare the natural heart circulation and prosthetic circulation. After BVB pumping was initiated, the natural heart was electrically fibrillated. Renal sympathetic nerve activity (RSNA) was recorded to analyze sympathetic outflow. Coherence function between the arterial pressure and RSNA was calculated to evaluate the linearity of the baroreflex system. The largest peak coherency was observed when BVB was driven at the frequency of natural heart beat prior to electrical fibrillation, which suggests that the baroreflex system shows the largest linearity at this frequency. These results suggest the possibility that the natural heart heat frequency is the setting frequency at which the baroreflex system transfers the hemodynamic rhythm to the sympathetic outflow.

SummaryUsing our “echo-dynamography”, blood flow structure and flow dynamics during ventricular systole were investigated in 10 normal volunteers. The velocity vector distribution demonstrated blood flow during ejection was laminar along the ventricular septum. The characteristic flow structure was observed in each cardiac phases, early, mid- and late systole and was generated depending on the wall dynamic events such as peristaltic squeezing, hinge-like movement of the mitral ring plane, bellows action of the ventricle and dimensional changes in the funnel shape of the basal part of the ventricle, which were disclosed macroscopically by using the new technology of high speed scanning echo-tomography and microscopically by the strain rate distribution measured by phase tracking method.The pump function was reflected on the changes in the flow structure represented by the flow axis line distribution and the acceleration along the flow axis line. The acceleration of the ejection had three modes, “A”, “B” and “C”, and generated by the wall dynamic events. “A” appeared from the apical to the outflow area along the main flow axis line, “B” along the anterior mitral leaflet and the branched flow axis line, and “C” generated by the high speed vortex behind the mitral valve. The magnitude of the acceleration was estimated quantitatively from the velocity gradient along the flow axis line. Macroscopic and microscopic asynchrony in the myocardial contraction and extension appeared systematically in the local part of the ventricular wall, which was helpful for making the flow structure and for performing the smooth pump function.

Background Although the deformability of the left ventricular (LV) wall appears to be important in maintaining effective cardiac performance, this has not been debated by anyone, probably owing to the difficulties of the investigation. Objectives This study applies a new technology to demonstrate how the LV wall deforms so as to adjust for optimum cardiac performance. Subjects and methods Ten healthy volunteers were the subjects. Using echo-dynamography, an analysis at the “microscopic” (muscle fiber) level was done by measuring the myocardial axial strain rate (aSR), while the “macroscopic” (muscle layer) level contraction-relaxation/extension (C-R/E) properties of the LV wall were analyzed using high frame rate 2D echocardiography. Results Deformability of the LV was classified into three types depending on the non-uniformity of both the C-R/E properties and the aSR distribution. “Basic” deformation (macroscopic): The apical posterior wall (PW) thickness change was concentric and monophasic, whereas it was eccentric and biphasic in the basal part. This deformation was large in the PW, but small in the interventricular septum (IVS). The elongation of the mitral ring diameter and the downward movement of its posterior part were shown to be concomitant with the anterior extrusion of the PW. “Combined” deformation (macroscopic and microscopic): This was observed when the basic deformation was coupled with the spatial aSR distribution. Three patterns were observed: (a) peristaltic; (b) bellows-like; and (c) pouch-like. “Integrated” deformation: This was the time serial aSR distribution coupled with the combined deformation, illustrating the rotary pump-like function. The deformability of the LV assigned to the apical part the control of pressure and to the basal part, flow volume. The IVS and the PW exhibited independent behavior. Conclusions The non-uniformity of both the aSR distribution and the macroscopic C-R/E property were the basic determinants of LV deformation. The apical and basal deformability was shared in LV mechanical function.

To improve the evaluation of regional wall motion abnormalities (WMA) during stress echocardiography, the parameters of the wall thickness change, excursion and stroke volume, with time-dependent changes in two regional portions of the interventricular septum and the posterior wall evaluated with M-mode ultrasonography are proposed. Response to the dipyridamole stress test was studied in two normal subjects and eight subjects with coronary disease. Regional wall motion and stroke volume were measured, and the results were compared with results obtained with coronary angiography, 2-D echography, and radioisotope scintigraphy. In normal subjects, these parameters showed only monotonous change with the passage of time. In patients with coronary artery disease, however, discrepancy in wall thickness and excursion between the interventricular septum and the posterior wall appeared within 1 to 3 minutes after the start of the test. Thus, despite the limitation of the examined area imposed by use of M-mode, the motion of the interventricular septum and the posterior wall described the details of WMA and an ischemic state.

ObjectivesUsing newly developed ultrasonic technology, we attempted to disclose the characteristics of the left ventricular (LV) contraction–extension (C–E) property, which has an important relationship to LV function.MethodsStrain rate (SR) distribution within the posterior wall and interventricular septum was microscopically measured with a high accuracy of 821μm in spatial resolution by using the phase difference tracking method. The subjects were 10 healthy men (aged 30–50 years).ResultsThe time course of the SR distribution disclosed the characteristic C–E property, i.e. the contraction started from the apex and propagated toward the base on one hand, and from the epicardial side toward the endocardial side on the other hand. Therefore, the contraction of one area and the extension of another area simultaneously appeared through nearly the whole cardiac cycle, with the contracting part positively extending the latter part and vice versa. The time course of these propagations gave rise to the peristalsis and the bellows action of the LV wall, and both contributed to effective LV function.The LV contraction started coinciding in time with the P wave of the electrocardiogram, and the cardiac cycle was composed of 4 phases, including 2 types of transitional phase, as well as the ejection phase and slow filling phase. The sum of the measurement time duration of either the contraction or the extension process occupied nearly equal duration in normal conditions.ConclusionThe newly developed ultrasonic technology revealed that the SR distribution was important in evaluating the C–E property of the LV myocardium. The harmonious succession of the 4 cardiac phases newly identified seemed to be helpful in understanding the mechanism to keep long-lasting pump function of the LV.

Background: We reported an increased occurrence of cardiovascular diseases (CVDs) after the Great East Japan Earthquake by examining ambulance records, but it had to be confirmed by cardiologists. Methods and Results: We enrolled patients admitted to the cardiology department of the 10 hospitals in the disaster area from 4 weeks prior to 15 weeks after March 11 in the years 2008–2011 (n=14,078). The weekly occurrence of several CVDs, including heart failure (HF), pulmonary thromboembolism (PTE) and infectious endocarditis (IE), was sharply and significantly increased after the Earthquake. Conclusions: The Disaster caused significantly increases in the occurrence of HF, PTE and IE. (Circ J 2013; 77: 490–493)

Radiation safety education/training is essential and is associated with a reduction in the radiation dose to both patients and staff. We used a questionnaire to assess the level of radiation safety knowledge among nurses working at Tohoku Kosei-Nenkin Hospital. Some nurses were also interviewed. The results of our study indicate that the nurses had insufficient radiation safety knowledge and that a high percentage of nurses were concerned about the health hazards of radiation. Moreover, more than 80% of the nurses expressed an interest in attending periodic radiation safety seminars. Appropriate radiation safety training is required to reduce nurse radiation doses, and an understanding of radiation safety can help to optimize the patient dose.

Summary Background The existence as well as the exact genesis of left ventricular suction during rapid filling phase have been controversial. In the present study, we aimed at resolution of this problem using noninvasive and sophisticated ultrasonic methods. The clinical meaning was also documented. Methods Ten healthy male volunteers were examined by 2D echocardiography and echo-dynamography which enables us to obtain detailed instantaneous data of blood flow and wall motion simultaneously from the wide range of the left ventricle. The correlation of blood flow and wall motion was also studied. Results Rapid ventricular filling was divided into 2 phases which had different physiology. The early half (early rapid filling: ERF) showed the effect which was alike drawing a piston. This was proved by the shape of the velocity of inflow and the basal muscle contraction which actively assisted extension of the relaxed apical and central parts of the left ventricle, giving the negative pressure which causes the ventricular suction. The later half (late rapid filling: LRF) showed the turning of the fundamental flow and the squeezed basal part just like the sphincter in addition to the expansion of the apical and central portions of the left ventricle, and all of these cooperatively augmented the suction effect. Conclusion Ventricular suction does exist to help ventricular filling. Simultaneous appearance of the contraction in the basal part and the relaxation or extension in the apical part during the post-ejection transitional period was made to occur the suction in the LV. And it can be said that the suction appeared in the late stage of systole as the one of the serial systolic phenomena.

In the present study, “Electronic Doctor's Bag” which is a tele-healthcare tool for home-visit medical service using the mobile communications environment has been proposed and evaluated by preliminary experiments. It was shown that its basic function was sufficiently evaluated by a few doctors and nurses but further improvement in portability and operability is required on the basis of much more opinions of medical and nursing professionals.

Objectives: The aim of this study was to evaluate the safety and effectiveness of a 0.010-inch guidewire and a balloon catheter for treatment of chronic total occlusion (CTO). Background: Pathological studies have shown that 60–70% of CTO lesions have microchannels of sizes equal to or less than 0.010 inch. Methods: The PIKACHU registry is a prospective, multicenter registry study. A 0.010-inch guidewire had to be used as the first guidewire to attempt to pass the CTO lesion. The primary endpoint was device success using a 0.010 system. Results: A total of 141 patients with 141 lesions were enrolled. The median duration of occlusion was 9 months (range 3–156). Average guiding catheter size was 5.8 ± 0.7 Fr. and TRI was 76.6 %. CTOs were mostly between 10–20 mm long, observed in 53 occlusions. There were 107 lesions (75.9%) with bending of more than 45 degrees. Calcification was seen in 91 lesions (64.5%). A 0.010-inch guidewire was successfully passed through in 97 of 141 lesions (68.8%). A 0.010-inch guidewire compatible balloon catheter was passed in 87 of the 97 lesions (88.7%) and final PCI success was achieved in all the cases. The overall clinical success rate was 87.9% (124/141). No MACE or bleeding complications were observed. Conclusion: The PIKACHU registry data suggest that the 0.010-inch system is safe and practicable for treatment of CTO lesions. © 2010 Wiley-Liss, Inc.

To evaluate the effect of total artificial heart replacement on the autonomic nervous system, sympathetic neurograms were analyzed by power spectrum and coherence function. Two pneumatically driven, sac type ventricular assist devices were implanted as biventricular bypasses (BVB) in adult, mongrel dogs. After initiation of BVB pumping, the natural heart was electrically fibrillated to form a BVB TAH model. Renal sympathetic nerve activity (RSNA) was recorded using a bipolar electrode attached to the left renal sympathetic nerve. RSNA was amplified and integrated by use of an R-C integrator. Power spectra of the RSNA and values of squared coherence between the arterial pressure wave form and the RSNA were calculated by computer. In animals with total artificial hearts (TAHs), coherence at the cardiac rhythm frequency was decreased, and coherence at the TAH pumping rhythm frequency was increased. These results indicate that the arterial pulse wave observed in TAH animals contributed to the sympathetic neurogram.

Circulatory maintenance with a left ventricular assist device (LVAD) alone during cardiac arrest until heart transplantation has been evaluated. To assess the effect on the autonomic nervous system, the sympathetic neurogram was analyzed by power spectrum and coherence function. LVAD were inserted between the left atrium and the descending aorta in seven adult mongrel dogs and ventricular fibrillation was induced electrically. Renal sympathetic nerve activity (RSNA) was detected by bipolar electrodes attached to the left renal sympathetic nerve. Values of squared coherence between the arterial pulse wave and RSNA were calculated. Under the condition of circulatory maintenance with only LVAD, coherence at the cardiac rhythm frequency was decreased, and coherence at the LVAD pumping rhythm frequency was increased. These results indicate that the arterial pulse wave observed during maintenance of the circulation with only LVAD contributed to the sympathetic neurogram.

Objective: To evaluate the safety and feasibility of a new 0.010-inch guidewire and a specialized balloon catheter for the 0.010-inch guidewire in routine percutaneous coronary intervention (PCI). Background: Several reports have shown that a new 0.010-inch system is effective for specific situations where reduction of catheter size may be necessary. However, the safety of this system in routine PCI is unknown. Methods: The IKATEN registry is a prospective, multicenter, nonrandomized registry study. Patients who underwent elective PCI with a 0.010-inch guidewire and its associated balloon catheter as primary devices were enrolled. The coprimary endpoints were clinical success and device success rates. The secondary endpoints were major adverse cardiac events (MACE) and bleeding complications. Results: A total of 133 patients with 148 lesions were enrolled. The majority were male (75.3%), and mean age was 68 ± 10 years. Type B2/C lesions comprised 60% of the lesions, prevalence of chronic total occlusion (CTO) was 16.9%, and bifurcation lesions were found in 22.3% of patients. A transradial approach was used in 79.7% of patients, and the average guiding catheter size was 5.1 ± 0.4 Fr. Clinical success rate was 99.2%, and device success rate was 99.3%. Device failure occurred only in one case of chronic total occlusion because of unsuccessful guidewire passage. No MACE or bleeding complications were reported except for a small hematoma at the puncture site in one patient. Stent delivery success rate on 0.010-inch guidewire was 93.9% because of failure of stent balloon to pass eight lesions. Conclusion: The IKATEN registry data suggest that the 0.010-inch system is safe and its use is feasible in routine PCI including bifurcation and CTO lesions. © 2009 Wiley-Liss, Inc.

In order to evaluate the effect of ventricular assist device (VAD) driving on the autonomic nervous system, sympathetic neurograms during left ventricular (LV) assistance were analyzed by power spectrum and coherence function. Our TH–7B pneumatically–driven sac–type VAD was used in seven adult mongrel dogs. VADs were inserted between the left atrium and the descending aorta. Renal sympathetic nerve activity (RSN A) was detected by use of bipolar electrodes attached to the left renal sympathetic nerve via a retroperitoneal approach. Values of squared coherence between the arterial, pulse wave and RSNA were measured at the same frequency of cardiac and VAD pumping rhythms. During LV assistance, coherence at the cardiac rhythm frequency was decreased, and coherence at the VAD pumping rhythm frequency was increased. These results indicate that the arterial pulse wave, which was produced by the VAD assistance, contributed to postganglionic sympathetic nerve activity.

To determine the effect of left ventricular assist device (LVAD) pumping on sympathetic tone, renal sympathetic nerve activity (RSNA) was detected in acute animal experiments. Our TH-7B pneumatically driven, sac-type ventricular assist device was used in 7 adult mongrel dogs. RSNA was detected by the use of bipolar electrodes attached to the left renal sympathetic nerve. RSNA was amplified and integrated by use of an R-C integrator circuit. The area of the integrated nerve discharge per unit time was calculated in the computer system and expressed as RSNA per unit time. During LVAD pumping, RSNA decreased with increase in blood pressure, with an increase in pulmonary artery flow, and with a decrease in left atrial pressure. These data suggest that LVAD has an effect on the sympathetic nervous system which is mediated by the aortic and cardiopulmonary baroreflex system.

It is very important to grasp the fluid-mechanial property of a prosthetic valve on the various driving conditions, in order to develop a ventricular assist device (VAD). Therefore, the flow characteristics of a newly designed ball valve which consisted of a silicone ball and a polycarbonate housing was analyzed by means of the quantitative flow visualization technique and was compared with the Bjork-Shiley prosthetic valve (BS-19ABP, spherical). The flow visualization were carried out on the four different flow rate conditions (3.0, 2.0, 1.5 and 1.0 L/min). It was observed that the decrease of the flow rate influenced neither on the maximum velocity nor on the velocity vector distributions of a ball valve in comparison with the Byirk-Shiley valve. Furthermore, even on the low flow rate condition (1.0 L/min), the decreases of the flow velocity and the shear rate, which might cause the thrombus formation, were not observed in the lower part of a ball valve. In conclusion, a newly designed ball valve has the fluid-mechanical property which meets the requirement of VAD.

We report a case of angiosarcoma of the right atrium presenting superior vena cava syndrome. The patient was a 61-year-old man. Echocardiography, CT and MRI revealed a tumor arising in the anterior wall of the right atrium. The tumor was hen-egg sized and unresectable because of the invasion of the pericardium, the right ventricular wall and the superior vena cava. An open biopsy and left brachiocephalic vein-right atrium bypass grafting were performed. The pathological diagnosis was angiosarcoma. The patient agreed to chemotherapy with docetaxel, which is known to be often effective against angiosarcoma of the scalp or face. After 5 courses of docetaxel administration (30 mg/m2 on day 1, 8 and 15 followed by 14 days. rest as one course), echocardiography and CT showed a remarkable tumor reduction, which was evaluated as a partial response. The chemotherapy was suspended for 8 months because of neutropenia and general fatigue as side effects of docetaxel. The administration of docetaxel was resumed and 4 courses were performed. The tumor, however, became resistant to docetaxel and formed metastatic involvements in the liver. Following treatments with paclitaxel, IL-2 and CPT-11 were ineffective for the primary tumor and liver metastases. He died of cardiac tamponade caused by massive hemorrhage into the pericardiac space from the tumor surface. He had long-term survival 31 months after the diagnosis. An effective treatment for cardiac angiosarcoma has not yet been established. Chemotherapy with docetaxel should be considered in the treatment of patients with cardiac angiosarcoma.

Since cardiac interventional procedures deliver high doses of radiation to the physician, radiation protection for the physician in cardiac catheterization laboratories is very important. One of the most important means of protecting the physician from scatter radiation is to use additional lead shielding devices, such as tableside lead drapes and ceiling-mounted lead acrylic protection. During cardiac interventional procedures (cardiac IVR), however, it is not clear how much lead shielding reduces the physician dose. This study compared the physician dose [effective dose equivalent (EDE) and dose equivalent (DE)] with and without additional shielding during cardiac IVR. Fluoroscopy scatter radiation was measured using a human phantom, with an ionization chamber survey meter, with and without additional shielding. With the additional shielding, fluoroscopy scatter radiation measured with the human phantom was reduced by up to 98%, as compared with that without. The mean EDE (whole body, mean+/-SD) dose to the operator, determined using a Luxel badge, was 2.55+/-1.65 and 4.65+/-1.21 mSv/year with and without the additional shielding, respectively (p=0.086). Similarly, the mean DE (lens of the eye) to the operator was 15.0+/-9.3 and 25.73+/-5.28 mSv/year, respectively (p=0.092). In conclusion, although tableside drapes and lead acrylic shields suspended from the ceiling provided extra protection to the physician during cardiac IVR, the reduction in the estimated physician dose (EDE and DE) during cardiac catheterization with additional shielding was lower than we expected. Therefore, there is a need to develop more ergonomically useful protection devices for cardiac IVR.

A new horizon of long t ime (more than 24 hours) digital holter ECG has been developing based upon digital technology using digital audio tape (DAT) and miniaturizing technique. The recorder employed a newly d eveloped very LSIs and time lapse system to obtain long t ime r ecording, low frequency signal and/or play back. With this system we have realized high quality and reliable signal r ecording also for the r ecording of the other biological informations, such a s blood pressure, body temperature, respiratory analysis, EEG and so on.

We present a case of a localized left ventricular (LV) aneurysm in a 72-year-old woman with sudden onset of severe chest pain. A left ventriculogram revealed a small saccular outpouching protruding from the apex accompanied with narrow neck connection to the ventricular cavity. Both coronary arteries and global function were normal. We preoperatively diagnosed her as having an impending rupture in the congenital LV diverticulum because no inflammatory myocardial disease was suggested by general laboratory tests. After successful surgical treatment, microscopic examination for the myocardial specimens was performed and revealed diffuse lymphocytic infiltration associated with focal necrosis of myocardium. Histological findings were consistent with those of acute lymphocytic myocarditis. Without histological confirmation, an aneurysm caused by silent myocarditis might be misdiagnosed as a diverticulum.

A 52-year-old woman suffered from acute massive myocardial infarction in association with a large thrombus in the ascending aorta. She was a moderate smoker and was taking hormone supplement therapy for menopausal hormone insufficiency and the contraceptive pill for endometriosis. Cardiac angiography revealed a large mobile filling defect close to the orifice of the left coronary artery, but the left coronary artery could not be visualized. Her hemodynamic condition was impaired so greatly that intraarterial counterpulsation and intravenous thrombolysis was immediately performed. The thrombus dissolved in 1 h and recanalization of the left coronary artery was achieved without serious systemic thromboembolism. She has been doing well with no cardiac events for 7 years. This is the second report of a large thrombus in ascending aorta being the cause of acute myocardial infarction in the whole territory of the left coronary artery, and the first to diagnose such a thrombus antemortem and treat it successfully.

Acute coronary occlusion may occur in weak coronary atherosclerotic lesions, including dissection, ulceration or thrombus. In some cases of occlusion “bail-out” is performed by using recently developed New Devices. However, these have not yet completely solved the problem to this end, we designed a new method of coronary revascularization, the Intracoronary Local Adhesive Delivery Technique, utilizing antithrombotic and absorbable adhesive injected locally into the fragile and morbid arterial wall using a drug delivery PTCA catheter more flexible than the existing New Devices. This adhesive strengthened and hardened the lesions. In this study, we examined the efficacy of making an adhesive cylinder in arteries of similar size to the coronary, through acute animal experiments using the existing clinical adhesives and drug delivery PTCA catheters and 12 femoral arteries of adult goats. We were successful in forming firm tunnels along the inside of six arteries, infused with approximately 0.04 ml Cyanoacrylate. These tunnels were observed with intravascular ultrasound (IVUS) imaging and evaluated microscopically. These results suggest the feasibility of this method as a new approach for making synthetic resinous stents.

It has been frequently reported that while myocardial viability is neglected in conventional methods of diagnosis such as left ventriculography, ECG, and exercise thallium-201 myocardial scintigraphy (Ex-Tl), revascularization often results in improving left ventricular wall motility. In the present study, the authors contrived a method to accurately evaluate the viability ot the myocardium by means of exercise rehabilitation, and tested the method in clinical cases. Among patients with myocardial infarction, we selected a patient with negative viability in the diseased area as determined by chronic ECG, left ventriculography (LVG), coronary angiography and Ex-Tl. This patient went through two weeks of active exercise rehabilitation gauged with an ergometer, and was then re-examined by Ex-Tl. After the evaluation, revascularization was performed for the patient who demonstrated viability of the infarcted myocardium in EX-T1 after rehabilitation, and significant improvement in contractility was shown in the chronic LVG. These findings indicate that our method of detecting potential viability of the infarcted myocardium is of clinical significance.

A new method for indirect and real-time estimation of the cardiac output of the circulatory system supported by the left ventricular assist device (LVAD) was proposed. This method has low invasiveness and is useful for clinical application of the LVAD since it needs only two measurements: the outflow rate of blood from the LVAD and the aortic pressure. The proposed method is based on a system identification technique for the time series model of the cardiovascular system and requires less computational time than other methods with similar estimation accuracy. Hence, the proposed method could be implemented in a personal computer system and realize the on-line and real-time estimation of the instantaneous outflow rate of the natural heart. The efficiency and limitation of the method were discussed on the basis of the results obtained from in vitro experiment using a mock circulatory system and in vivo experiment using an adult goat. It was revealed that the method could obtain a fairly high correlation coefficient between the true stroke volume of the natural heart and its estimate of more than 0.99 (in vivo) or 0.95 (in vivo). This means that there is a fair possibility of applying the proposed estimation system to the clinical use.

In order to determine optimal drive conditions for the total artificial heart (TAH) from the neurophysiological point of view, power spectral analysis of the hemodynamic parameters in animals chronically implanted with TAH was performed to analyze the rhythmical fluctuations that reflect the operation of cardiovascular regulatory systems. Two ventricular assist devices were implanted as total biventricular bypasses (BVB) in chronic animal experiments with adult goats. Natural hearts were then electrically fibril-lated to constitute the BVB type of TAH model for comparison of the circulation in animals with a natural heart and those with a TAH. Mayer waves and respiratory waves were clearly observed in the arterial pressure of the TAH animal, these fluctuations being significantly influenced by the TAH driving conditions. These results suggest that fluctuations in the hemodynamics of animals with TAH can provide information for TAH control systems.

In order to investigate the origin of the fluctuations in hemodynamic parameters, total artificial heart (TAH) replacement was performed in chronic animal experiments using adult goats. Two ventricular assist devices were implanted as total biventricular bypass (BVB) and natural heart was electrically fibrillated. The results suggest that fluctuations in the hemodynamics of the TAH animal are originated from the periodicity of the peripheral and pulmonary vascular resistance.

This paper presents a new method of keeping one of the most suitable driving conditions for regulating the outflow volume from the ventricular-assist device (VAD). The experimental results from a mock circulatory system have shown that the relationship between the stroke volume and the systolic duration of the VAD can be specified by the combination of characteristic curves of the positive and negative drive pressures. The optimal operating point on the characteristic curve have been defined as the point at which thrombosis on the blood-contacting surface and hemolysis due to mechanical damage can be avoided and at which the driving energy can be minimized. The present analysis has been revealed that the optimal operating point is the vertex of the triangular figure obtained from the characteristic curve. The algorithms for keeping the optimal operating point and for regulating the stroke volume have been also proposed.

YAMBE, T., NITTA, S., CHIBA, S., SAIJOH, Y., NAGANUMA, S., AKIHO, H., KAKINUMA, Y., IZUTSU, K., KIKUCHI, Y., NAGANUMA, T., SUGAWARA, S., TANAKA, M., MEGURO, T., SASAKI, H., MITSUOKA, M., TERASAWA, Y., NITTA, K., KATAHIRA, Y., OHTOMO, T., ENDOH, N., TAKEDA, H., SONOBE, T., TAKAHASHI, K., MIURA, M., SATO, N. and MOHRI, H. Silent Obstruction of the Coronary Stenosis between Diagnostic Angiography and Later Percutaneous Transluminal Coronary Angioplasty without Myocardial Infarction. Tohoku J. Exp. Med., 1991, 163 (3), 167-174 - Among 204 patients with severe coronary artery senosis amenable to percutaneous transluminal coronary angioplasty (PTCA), 5 (2.5%) developed new silent total coronary occlusion of the vessel to be dilated without any chest symptom during the period between diagnostic coronary angiography and repeat coronary angiography at the time of the operation. We evaluated the clinical and angiographical characteristics of the patients with silent obstruction of the coronary artery in a short time, compared with the patients with unstable angina pectoris, who is considered to be suffering from acute myocardial infarction with severe chest symptom. None of the clinical variables studied showed a significant difference between the two groups. Among the angiographic variables, the degree of collateral was higher and impaired coronary perfusion distal to the lesion was more frequently found in unstable angina group. These results suggest that unstable angina is in a later stage of the ischemic heart disease compared with the time of the diagnostic angiography in patients with silent obstruction. Silent obstruction of high degree coronary stenosis is presumably due to the development of collateral circulation.

A wide variety of clinical blood pumps including powering systems have been developed and evaluated for totally implantable support systems [1–6]. However, there are still several serious problems, such as thromboembolic episodes, size, and weight, affecting prolonged survival of a total system inside the body.

In order to develop the real-time control system of a total artificial heart (TAH), we use the sympathetic tone and the hemodynamic parameters. Moving averages of the mean left atrial pressure and mean aortic pressure were used as the parameters of the preload and the afterload in the circulatory system. Also, renal sympathetic nerve activity (RSNA) was utilized as the parameter of the sympathetic tone. A functional formula which prospectively indicated cardiac output, was calculated using the multiple regression analysis of the time series data in the acute animal experiments using adult mongrel dogs. Also, a functional formula which prospectively indicated heart rate was determined through the time series data of the RSNA.

We have been involved in the development of a clinical ventricular assist device (VAD) system. Here, we report our investigation of in vitro and in vivo stability and sensibility of pressure microsensors. The sensors were mounted in the inflow and outflow cannulae wall to measure the left atrial and aortic pressures during VAD pumping. The pressure sensitive surface of the piezoresistive effect absolute pressure sensor was coated with a thromboresistant polymer, as was the inner surface of the cannulae of the VAD. In the in vitro and chronic animal experiments which were of more than a month duration, reliable stability and sensitivity, without any thrombus formation on the blood contacting surface of the sensors, and high sensitivity were observed. After chronic experiments, the sensitivity of sensors was reevaluated in the mock circulatory system as compared to reference values. The relationship between the output of the micro-sensors and the reference value was linear and correlated well.

For visualizing blood flow in the human heart noninvasively, the stream‐function method based on the ultrasonic Doppler technique was introduced. In this method intracardiac blood flow is displayed as a two‐dimensional streamline distribution pattern. In normal hearts, blood flow in the left ventricle during systole is displayed as a fan‐shaped streamline pattern converging from the whole ventricular wall toward the outflow tract, and in diastole the streamline distribution shows fan‐shaped divergence from the left atrium toward the whole ventricular wall. The fan‐shaped streamline distribution is considered to reflect the uniform contractability and extensibility in the whole ventricular wall. On the other hand, in infarcted hearts with regional asynergy in the left ventricle, the streamline pattern is remarkably different. In systole, the streamline pattern at the normokinetic portion is the same as that in normals, but in the infarcted portion, the streamlines show a crooked pattern caused by the inflo...