A 38-year-old man was diagnosed with acute type A aortic dissection and severe aortic regurgitati... more A 38-year-old man was diagnosed with acute type A aortic dissection and severe aortic regurgitation, and taken immediately to the operating room for repair of the ascending aorta using the Bentall procedure. The presence of the anomalous right coronary artery was revealed at the time of the procedure, and was repaired with single coronary button technique. Some case reports have described anomalous coronary artery in association with acute myocardiac infarction or angina pectoris. This report describes a case of anomalous coronary artery diagnosed during an emergency operation for aortic dissection.
American Journal of Physiology-heart and Circulatory Physiology, Oct 15, 2014
After myocardial infarction, a poorly contracting nonischemic border zone forms adjacent to the i... more After myocardial infarction, a poorly contracting nonischemic border zone forms adjacent to the infarct. The cause of border zone dysfunction is unclear. The goal of this study was to determine the myofilament mechanisms involved in postinfarction border zone dysfunction. Two weeks after anteroapical infarction of sheep hearts, we studied in vitro isometric and isotonic contractions of demembranated myocardium from the infarct border zone and a zone remote from the infarct. Maximal force development (Fmax) of the border zone myocardium was reduced by 31 ± 2% versus the remote zone myocardium (n = 6/group, P < 0.0001). Decreased border zone Fmax was not due to a reduced content of contractile material, as assessed histologically, and from myosin content. Furthermore, decreased border zone Fmax did not involve altered cross-bridge kinetics, as assessed by muscle shortening velocity and force development kinetics. Decreased border zone Fmax was associated with decreased cross-bridge formation, as assessed from muscle stiffness in the absence of ATP where cross-bridge formation should be maximized (rigor stiffness was reduced 34 ± 6%, n = 5, P = 0.011 vs. the remote zone). Furthermore, the border zone myocardium had significantly reduced phosphorylation of myosin essential light chain (ELC; 41 ± 10%, n = 4, P < 0.05). However, for animals treated with doxycycline, an inhibitor of matrix metalloproteinases, rigor stiffness and ELC phosphorylation were not reduced in the border zone myocardium, suggesting that doxycycline had a protective effect. In conclusion, myofilament dysfunction contributes to postinfarction border zone dysfunction, myofilament dysfunction involves impaired cross-bridge formation and decreased ELC phosphorylation, and matrix metalloproteinase inhibition may be beneficial for limiting postinfarct border zone dysfunction.
PurposeMyocardial strain is increasingly used to assess left ventricular (LV) function. Incorpora... more PurposeMyocardial strain is increasingly used to assess left ventricular (LV) function. Incorporation of LV deformation into finite element (FE) modeling environment with subsequent strain calculation will allow analysis to reach its full potential. We describe a new kinematic model‐based analysis framework (KMAF) to calculate strain from 3D cine‐DENSE (displacement encoding with stimulated echoes) MRI.MethodsCine‐DENSE allows measurement of 3D myocardial displacement with high spatial accuracy. The KMAF framework uses cine cardiovascular magnetic resonance (CMR) to facilitate cine‐DENSE segmentation, interpolates cine‐DENSE displacement, and kinematically deforms an FE model to calculate strain. This framework was validated in an axially compressed gel phantom and applied in 10 healthy sheep and 5 sheep after myocardial infarction (MI).ResultsExcellent Bland–Altman agreement of peak circumferential (Ecc) and longitudinal (Ell) strain (mean difference = 0.021 ± 0.04 and −0.006 ± 0.03, respectively), was found between KMAF estimates and idealized FE simulation. Err had a mean difference of −0.014 but larger variation (±0.12). Cine‐DENSE estimated end‐systolic (ES) Ecc, Ell and Err exhibited significant spatial variation for healthy sheep. Displacement magnitude was reduced on average by 27%, 42%, and 56% after MI in the remote, adjacent and MI regions, respectively.ConclusionsThe KMAF framework allows accurate calculation of 3D LV Ecc and Ell from cine‐DENSE.
Taurine attenuates oxidative damage to DNA (Messina and Dawson, 2000). Taurine increases the expr... more Taurine attenuates oxidative damage to DNA (Messina and Dawson, 2000). Taurine increases the expression of mitochondria-stabilizing anti-apoptotic Bcl-2 protein while decreasing that of the pro-apoptotic Bax protein and p53 the apoptosis initiator gene (Takahashi et al., 2003), rendering cultured rat cardiomyocytes resistant to hypoxia-induced injury. However, it is not clear whether aerobic or anaerobic mechanisms mediate those anti-apoptotic effects. The hypothesis that taurine preserves aerobic energy and enzyme activities and therefore provides a better function of myocardium subjected to ischemia/reperfusion was now tested in two groups of isolated rat hearts (a) in normothermic ischemia induced while beating, and (b) when high-K-depolarized and cold-preserved for 6 hours.
Introduction: Cardiac pacing for small children has been performed using a myocardial lead. Intra... more Introduction: Cardiac pacing for small children has been performed using a myocardial lead. Intravenous pacemaker lead implantation has a lot of advantages such as lower frequency of exit block and better pacing threshold compering to myocardial lead. However, intravenous pacemaker lead implantation has not been aggressively performed, because this approach for small children requires consideration of future growth, an appropriate entry site to avoid venous obstruction, and selection of lead. Patient and Method: The patient is a 4-year-old male underwent total correction of pulmonary atresia with ventricular septal defect following a lot of previous palliative surgery. Use of a myocardial lead was initially considered to treat sick sinus syndrome after total correction. However, it seemed difficult to attach a myocardial lead to the best place in the right atrium for AAI pacing, due to previous thoracotomies and cardiac surgery. Screw-in type lead was attached to the free wall of the right atrium and excess loop was left to adapt his growth. During the 16-year follow-up period, no adverse phenomenon such as an exit block, sensing failure, or free-floating of the lead were observed. Conclusion: The selection of a small size endocardial lead and an appropriate entry vein make implantation of an endocardial lead for small children easier and safety.
The Japanese Journal of Thoracic and Cardiovascular Surgery, Apr 1, 2004
Aneurysm of the innominate artery is uncommon compared with other peripheral aneurysms, and holds... more Aneurysm of the innominate artery is uncommon compared with other peripheral aneurysms, and holds the potential for rupture, embolization, or thrombosis as well as various complications caused by compression to the adjacent structures. The most effective treatment for this condition is surgical resection, but the earlier reports described high mortality rates. We report the case of an 83-year-old asymptomatic woman with an aneurysm in the innominate artery, which was successfully resected and repaired with the use of modern surgical techniques of hypothermic circulatory arrest and selective cerebral perfusion. Aggressive surgical intervention should be employed despite the fact that a patients is asymptomatic.
Kyobu geka. The Japanese journal of thoracic surgery, Sep 1, 2010
Median full-sternotomy carries a risk of sternal infection and lethal mediastinitis in cardiac su... more Median full-sternotomy carries a risk of sternal infection and lethal mediastinitis in cardiac surgery. We performed open-heart surgery through partial median sternotomy in 5 patients with tracheostomy. Coronary artery bypass grafting (CABG) was performed in 3 patients, aortic valve replacement in 1, and mitral valve replacement in 1. No operative deaths or complications related to wound infection occurred. Partial sternotomy represents a safe alternative in cardiac surgery in patients with tracheostoma.
A 38-year-old man was diagnosed with acute type A aortic dissection and severe aortic regurgitati... more A 38-year-old man was diagnosed with acute type A aortic dissection and severe aortic regurgitation, and taken immediately to the operating room for repair of the ascending aorta using the Bentall procedure. The presence of the anomalous right coronary artery was revealed at the time of the procedure, and was repaired with single coronary button technique. Some case reports have described anomalous coronary artery in association with acute myocardiac infarction or angina pectoris. This report describes a case of anomalous coronary artery diagnosed during an emergency operation for aortic dissection.
American Journal of Physiology-heart and Circulatory Physiology, Oct 15, 2014
After myocardial infarction, a poorly contracting nonischemic border zone forms adjacent to the i... more After myocardial infarction, a poorly contracting nonischemic border zone forms adjacent to the infarct. The cause of border zone dysfunction is unclear. The goal of this study was to determine the myofilament mechanisms involved in postinfarction border zone dysfunction. Two weeks after anteroapical infarction of sheep hearts, we studied in vitro isometric and isotonic contractions of demembranated myocardium from the infarct border zone and a zone remote from the infarct. Maximal force development (Fmax) of the border zone myocardium was reduced by 31 ± 2% versus the remote zone myocardium (n = 6/group, P < 0.0001). Decreased border zone Fmax was not due to a reduced content of contractile material, as assessed histologically, and from myosin content. Furthermore, decreased border zone Fmax did not involve altered cross-bridge kinetics, as assessed by muscle shortening velocity and force development kinetics. Decreased border zone Fmax was associated with decreased cross-bridge formation, as assessed from muscle stiffness in the absence of ATP where cross-bridge formation should be maximized (rigor stiffness was reduced 34 ± 6%, n = 5, P = 0.011 vs. the remote zone). Furthermore, the border zone myocardium had significantly reduced phosphorylation of myosin essential light chain (ELC; 41 ± 10%, n = 4, P < 0.05). However, for animals treated with doxycycline, an inhibitor of matrix metalloproteinases, rigor stiffness and ELC phosphorylation were not reduced in the border zone myocardium, suggesting that doxycycline had a protective effect. In conclusion, myofilament dysfunction contributes to postinfarction border zone dysfunction, myofilament dysfunction involves impaired cross-bridge formation and decreased ELC phosphorylation, and matrix metalloproteinase inhibition may be beneficial for limiting postinfarct border zone dysfunction.
PurposeMyocardial strain is increasingly used to assess left ventricular (LV) function. Incorpora... more PurposeMyocardial strain is increasingly used to assess left ventricular (LV) function. Incorporation of LV deformation into finite element (FE) modeling environment with subsequent strain calculation will allow analysis to reach its full potential. We describe a new kinematic model‐based analysis framework (KMAF) to calculate strain from 3D cine‐DENSE (displacement encoding with stimulated echoes) MRI.MethodsCine‐DENSE allows measurement of 3D myocardial displacement with high spatial accuracy. The KMAF framework uses cine cardiovascular magnetic resonance (CMR) to facilitate cine‐DENSE segmentation, interpolates cine‐DENSE displacement, and kinematically deforms an FE model to calculate strain. This framework was validated in an axially compressed gel phantom and applied in 10 healthy sheep and 5 sheep after myocardial infarction (MI).ResultsExcellent Bland–Altman agreement of peak circumferential (Ecc) and longitudinal (Ell) strain (mean difference = 0.021 ± 0.04 and −0.006 ± 0.03, respectively), was found between KMAF estimates and idealized FE simulation. Err had a mean difference of −0.014 but larger variation (±0.12). Cine‐DENSE estimated end‐systolic (ES) Ecc, Ell and Err exhibited significant spatial variation for healthy sheep. Displacement magnitude was reduced on average by 27%, 42%, and 56% after MI in the remote, adjacent and MI regions, respectively.ConclusionsThe KMAF framework allows accurate calculation of 3D LV Ecc and Ell from cine‐DENSE.
Taurine attenuates oxidative damage to DNA (Messina and Dawson, 2000). Taurine increases the expr... more Taurine attenuates oxidative damage to DNA (Messina and Dawson, 2000). Taurine increases the expression of mitochondria-stabilizing anti-apoptotic Bcl-2 protein while decreasing that of the pro-apoptotic Bax protein and p53 the apoptosis initiator gene (Takahashi et al., 2003), rendering cultured rat cardiomyocytes resistant to hypoxia-induced injury. However, it is not clear whether aerobic or anaerobic mechanisms mediate those anti-apoptotic effects. The hypothesis that taurine preserves aerobic energy and enzyme activities and therefore provides a better function of myocardium subjected to ischemia/reperfusion was now tested in two groups of isolated rat hearts (a) in normothermic ischemia induced while beating, and (b) when high-K-depolarized and cold-preserved for 6 hours.
Introduction: Cardiac pacing for small children has been performed using a myocardial lead. Intra... more Introduction: Cardiac pacing for small children has been performed using a myocardial lead. Intravenous pacemaker lead implantation has a lot of advantages such as lower frequency of exit block and better pacing threshold compering to myocardial lead. However, intravenous pacemaker lead implantation has not been aggressively performed, because this approach for small children requires consideration of future growth, an appropriate entry site to avoid venous obstruction, and selection of lead. Patient and Method: The patient is a 4-year-old male underwent total correction of pulmonary atresia with ventricular septal defect following a lot of previous palliative surgery. Use of a myocardial lead was initially considered to treat sick sinus syndrome after total correction. However, it seemed difficult to attach a myocardial lead to the best place in the right atrium for AAI pacing, due to previous thoracotomies and cardiac surgery. Screw-in type lead was attached to the free wall of the right atrium and excess loop was left to adapt his growth. During the 16-year follow-up period, no adverse phenomenon such as an exit block, sensing failure, or free-floating of the lead were observed. Conclusion: The selection of a small size endocardial lead and an appropriate entry vein make implantation of an endocardial lead for small children easier and safety.
The Japanese Journal of Thoracic and Cardiovascular Surgery, Apr 1, 2004
Aneurysm of the innominate artery is uncommon compared with other peripheral aneurysms, and holds... more Aneurysm of the innominate artery is uncommon compared with other peripheral aneurysms, and holds the potential for rupture, embolization, or thrombosis as well as various complications caused by compression to the adjacent structures. The most effective treatment for this condition is surgical resection, but the earlier reports described high mortality rates. We report the case of an 83-year-old asymptomatic woman with an aneurysm in the innominate artery, which was successfully resected and repaired with the use of modern surgical techniques of hypothermic circulatory arrest and selective cerebral perfusion. Aggressive surgical intervention should be employed despite the fact that a patients is asymptomatic.
Kyobu geka. The Japanese journal of thoracic surgery, Sep 1, 2010
Median full-sternotomy carries a risk of sternal infection and lethal mediastinitis in cardiac su... more Median full-sternotomy carries a risk of sternal infection and lethal mediastinitis in cardiac surgery. We performed open-heart surgery through partial median sternotomy in 5 patients with tracheostomy. Coronary artery bypass grafting (CABG) was performed in 3 patients, aortic valve replacement in 1, and mitral valve replacement in 1. No operative deaths or complications related to wound infection occurred. Partial sternotomy represents a safe alternative in cardiac surgery in patients with tracheostoma.
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Papers by Kiyoaki Takaba