Shigeo Yamauchi

Atrial activation during chronic atrial fibrillation in patients with isolated mitral valve disease

BACKGROUND A computerized 32-channel mapping system has been developed to investigate the characteristics of the atrial activation sequence. The system is capable of displaying sequential atrial maps and provides a rapid and dynamic means of verifying the activation sequence of atrial fibrillation. METHODS Using this system, we performed intraoperative atrial activation mapping in 10 patients with chronic atrial fibrillation who were undergoing isolated mitral valve operations. RESULTS Regular and repetitive activation (cycle length ranged from 131 to 228 milliseconds) originated in the left atrium in all 10 patients. Two patterns of repetitive activation in 2 patients and three patterns in 1 patient appeared alternately during the observation period in the left atrium. In contrast to the repetitive activation in the left atrium, the activation sequence of the right atrium was extremely complex and chaotic. In 7 of the 10 patients, the same pattern of right atrial activation was never repeated during the observation period. In 2 patients, revolution of repetitive activation in the right atrium sporadically appeared, but the pattern of activation immediately deteriorated to a complex and chaotic pattern. In 1 patient, repetitive activation emerged from the low lateral portion of the right atrium. Because our mapping technique was limited by the number of available atrial electrodes, discrete reentrant circuits or ectopic foci could not be demonstrated in the present study. However, the activation sequences during chronic atrial fibrillation suggested that (1) the left atrium would act as an electrical driving chamber for atrial fibrillation in the majority of the patients and (2) atrial activation patterns are different in each case. CONCLUSIONS Computerized intraoperative mapping should guide surgeons in determining the appropriate surgical procedure and facilitate operation for chronic atrial fibrillation associated with mitral valve disease.

Aortic dissection extending from the left coronary artery during percutaneous coronary angioplasty

A 72-year-old woman with acute aortic dissection as a complication of percutaneous coronary angioplasty was successfully treated. She received a graft replacement of the ascending aorta as well as triple coronary artery bypass grafts. The dissection had extended from the left coronary artery. Although acute aortic dissection is a rare complication of percutaneous coronary angioplasty, physicians and cardiac surgeons should keep its potential occurrence in mind.

Efficacy of intraoperative mapping to optimize the surgical ablation of atrial fibrillation in cardiac surgery

BACKGROUND Observation during open heart surgery in patients with chronic atrial fibrillation (AF) showed that the activation sequence of the left atrium was regular and that of the right atrium chaotic in most patients. We speculate that the left atrium plays a role as an important electrical driving chamber for AF and by mapping pre-operatively, optimal sites for the cryoablation can be determined to minimize the extensiveness of the cryolesions. METHODS Forty patients who underwent cardiac surgery and cryoablation guided by epicardial mapping data to eliminate AF originating from the left atrium were included in this study. RESULTS Sustained reentrant movement or repetitive firing from foci located in the right atrium was never observed. Foci or reentry circuits located in the left atrium were clearly identified in 11 cases. Nine of the 11 cases resumed sinus rhythm by placing cryolesions at these sites. Two cases needed a pacemaker implantation. The exact site had not been identified in the 29 remaining cases. In these 29 cases a left atrial posterior longitudinal linear cryoablation was placed. Sinus rhythm resumed in 22 cases. Six cases still remained in AF and a pacemaker was implanted in 1 case. Ultimately, in this series of operations sinus rhythm was resumed in 31 of 40 cases; AF remained in 6 of them and pacemaker implantation was required in 3 cases. CONCLUSIONS Mapping was useful to distinguish the two etiologies of the AF to facilitate optimal placement of the cryolesions. Sustained reentrant movement or repetitive firing from foci located in the right atrium was never observed and the left atrium played an important role as the electrical driving chamber for AF.

Simultaneous subclavian artery reconstruction in coronary artery bypass grafting

BACKGROUND Subclavian artery occlusive lesion, although rare, is sufficiently important to consider before coronary artery bypass grafting because it can cause not only symptoms of the lesion per se, but also the postoperative coronary-subclavian steal phenomenon. METHODS Four patients undergoing coronary artery bypass grafting received simultaneous reconstruction of the subclavian artery. During aortic cross-clamping, an 8-mm ring-reinforced polytetrafluoroethylene graft was attached to the aorta perpendicularly. The prosthetic graft was led to the proximal segment of the axillary artery through the second intercostal space and anastomosed to the inferior surface of the artery. RESULTS Three patients received unilateral reconstruction of the subclavian artery, whereas another received bilateral reconstruction. There were no complications related to the subclavian reconstruction procedure. Post-operative angiograms revealed excellent patency of the prosthetic grafts. All of the patients have been asymptomatic with follow-up periods ranging from 9 to 50 months. CONCLUSIONS To perform simultaneous subclavian artery reconstruction along with coronary artery bypass grafting, the aortoaxillary bypass procedure using an 8-mm polytetrafluoroethylene graft may be the method of choice because it has lower potential for complications and is less technically demanding.

Lymphoepithelioma-like carcinoma of the lung: case in which the patient has been followed up for 7 years postoperatively.

Primary lymphoepithelioma-like carcinoma (LELC) of the lung is a very rare disease. There is very little long term follow-up data about this disease. A 60-year-old woman was found to have abnormalities according to a routine chest X-ray examination. She was admitted to our hospital in March 1998. Since a malignant tumor of the right lung was suspected, surgical resection was performed in April of the same year. Pathological diagnosis was LELC of the lung. Its pathological stage was T1N0M0 stage IA. It has been reported that this carcinoma is associated with Epstein-Barr virus (EBV) infection. However, the patients tumor cells were negative for EBV as examined with RNA in situ hybridization technique. She is alive and has been free from recurrence of the disease over 7 years postoperatively.

Simultaneous surgical correction of a common atrium and impure flutter

We performed surgical correction and treatment of a common atrium and chronic impure flutter using a computerized mapping system in a 49-year-old man. A reentrant circuit was observed to exist around the left atrial appendage. In contrast to the regular activation in the left atrium, the activation sequence of the right atrium was extremely chaotic. Cryolesions were applied to the area of the reentrant pathway. After the operation, sinus rhythm was restored.

Continuous transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass in children

The purpose of this study was to evaluate the effectiveness of transoesophageal echocardiography monitoring during weaning from cardiopulmonary bypass after intracardiac repair in children. The left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion were monitored continuously by transoesophageal echocardiography in controls weaned easily from cardiopulmonary bypass (group A, n = 25), and those weaned with difficulty from cardiopulmonary bypass after mechanically assisted circulation (group B, n = 16). In group A, left ventricular ejection fraction and left ventricle wall motion were within normal range, and did not change significantly during weaning after cardiopulmonary bypass when compared with pre-bypass data. In contrast, left ventricular ejection fraction, left ventricular end-diastolic volume and left ventricle wall motion in group B during the first trial of weaning from bypass were significantly worsened. Hence, assisted circulation was performed until the data obtained via transoesophageal echocardiography improved with regard to maintenance of fluid balance, catecholamine dosage and assisted pump flow. All cases in group B were weaned safely from cardiopulmonary bypass despite their critical condition. In conclusion, continuous transoesophageal echocardiography monitoring may be a useful tool in children with severe heart failure for safe weaning from cardiopulmonary bypass after intracardiac repair.

Repair of an Abdominal Aortic Aneurysm with a Remarkably Dilated Meandering Artery: Report of a Case

A 73-year-old man on dialysis for chronic renal dysfunction was referred to our hospital for surgical treatment of an abdominal aortic aneurysm (AAA). Preoperative angiography showed a remarkably developed meandering artery branching from the inferior mesenteric artery (IMA). The superior mesenteric and celiac arteries were occluded at the origin, and all blood flow to the abdominal organs was apparently supplied by collateral circulation from the IMA. Considering the risk of mesenteric ischemia after aortic clamping in conjunction during surgery, we used a perfusion catheter with a 12-F balloon to create a shunt to the IMA from the subclavian artery. The operation was successful and the patient recovered uneventfully. We describe this surgical procedure for its effectiveness in preventing postoperative mesenteric ischemia in a rare case of an AAA with complex branching lesions.

The Clinical Significance of Performing Preoperative Angiography of the Internal Thoracic Artery in Coronary Artery Bypass Surgery

This study was designed to clarify the clinical significance of and indications for performing preoperative internal thoracic artery (ITA) angiography in patients undergoing coronary artery bypass surgery. A total of 300 possible candidates for coronary artery bypass grafting (CABG) underwent ITA angiography during diagnostic catheterization. Semi-selective angiography of bilateral ITAs were performed by injecting contrast medium manually with a 5-F right Judkins coronary catheter. The posteroanterior view of the arteriograms was recorded on a 35-mm cine film or a cut-film. Unusual angiographic findings of the ITAs were observed in nine patients (3%). These findings included: an atrophic ITA in three patients with ipsilateral subclavian artery occlusions; enlarged ITAs giving collaterals to the lower extremities in one patient with extensive aortoiliac occlusive disease; occluded ITAs in one patient with Takayasus arteritis and two patients with a history of CABG; and a small but nonsclerotic ITA in one patient. Atherosclerotic occlusive ITAs were found in only one patient. Thus, we concluded that routine preoperative angiography of the ITA is not necessary because it is rarely affected by atherosclerosis. However, it should be performed for any of the following reasons: a cervical or supraclavicular bruit; an upper extremity blood pressure difference of greater than 20 mmHg; an extensive aortoiliac occlusion; and certain disorders such as Takayasus arteritis or Kawasaki disease, or a history of open heart surgery.

“Hexatuple” coronary bypass with in situ arterial grafts

A fifty-seven year old male patient with severe three-vessel coronary artery disease underwent successful coronary bypass surgery in six vessels utilizing the in situ left internal thoracic and right gastroepiploic arteries. Each arterial conduit was anastomosed sequentially to as many as three coronary vessels respectively. Surgical results were excellent and the patient continues to do very well. A postoperative angiogram showed well-working arterial conduits without any anastomotic problems. Multiple sequential anastomoses of the in situ arterial conduits, although rather technically demanding, can provide better long-term results in patients requiring multiple coronary revascularization. When sequential anastomoses of the right gastroepiploic artery are being considered, the length and caliber of the artery should be evaluated by an angiogram since it varies in size compared to the internal thoracic artery.