Electromechanical synchronization of the heterotopic and native heart by dual atrial stimulation following heart transplantation.

After heterotopic heart transplantation, a 59-year-old woman presented with remarkable symptoms of breathlessness and fatigue, despite excellent donor heart function. Asynchrony of donor and native heart provoked haemodynamic instability. Dual atrial pacemaker implantation lead to linkage and synchronization of atrial and ventricular contraction in both the donor and native heart with the faster organ executing the synchronization. Remarkable relief of symptoms has been evident during the long-term follow-up.

The axillocoronary bypass. Blood flow and short-term graft histology in a porcine model.

BACKGROUND: Bypass grafts arising from the axillary artery may be indicated for complications during minimally invasive direct coronary artery bypass grafting, for redo operations and for management of a severely atherosclerotic ascending aorta. As basic data research on this technique is scanty, we investigated intraoperative function and postoperative morphology of axillocoronary bypass grafts in a porcine model. METHODS: Thirteen German domestic pigs received an axillocoronary vein graft (Group I, n=7) or an aortocoronary vein graft (Group II, n=6) to the left anterior descending artery. In Group I the proximal anastomosis was performed to the left axillary artery, and after partial rib resection the graft was brought transpleurally to the target vessel. In both groups the coronary anastomosis was carried out on the beating heart without cardiopulmonary bypass. Graft flow was measured using transit time ultrasonic flow probes. RESULTS: Intraoperatively all grafts showed a typical diastolic flow profile. Stable graft flow was lower in axillocoronary bypass grafts: 47 (30-60 mL/min) in Group I and 65 (35-126 mL/min) in Group II (p=0.005). Flow given as percentage of cardiac output, however, did not differ between the two grafts: 0.9 (0.6-1.2%) in Group I and 1.2 (0.8-2.4%) in Group II (p=NS). At day 4 after surgery there was no clear histologic predilection site for microtrauma and early degenerative changes in the axillocoronary graft. CONCLUSIONS: Axillocoronary bypass flow compares well with flow in the aortocoronary graft. Microtrauma after implantation and early degenerative changes in the axillocoronary vein bypass are not particularly impacted by the thoracic entry site.

Extraanatomical coronary artery bypass grafts on the beating heart for management of the severely atherosclerotic ascending aorta.

BACKGROUND: Crossclamping a severely atherosclerotic ascending aorta carries a significant risk of stroke in coronary artery bypass grafting. Besides other techniques aortic no touch concepts are increasingly applied for management of this problem. METHODS: Out of 407 patients undergoing epiaortic scanning during coronary artery bypass grafting 38 (9.3%) exhibited severe ascending aortic atherosclerosis. 22 of these patients (18 male, 4 female, age 72 (57-79) years, Parsonnet Score 11 (0-18), Euro Score 8 (2-13), McSPI Stroke Risk Index 6 (1-30) %) were operated on using a beating heart and aortic no touch technique. All patients received at least one internal mammary artery (IMA) in situ graft and additional extraanatomical bypass conduits: venous Y-graft from the IMA (n=14), arterial Y-graft from the IMA (n=3), vein graft from the axillary artery (n=3), vein graft from the IMA stump (n=2), vein graft from the innominate artery (n=2). RESULTS: No stroke occurred. The rate of perioperative myocardial infarction (CKMB rt; 50 U/l) was 5/22. Median ICU length of stay was 54 (15-1245) h. Hospital mortality was 2/22. Pre- and postoperative angina class (CCSC) were 3.3 +/- 0.9 and 1.4 +/- 0.9 respectively (p<0.001). After a median follow up period of 8 months 3 deaths, one stroke, and one myocardial infarction occurred. On 3D multislice CT scan reconstructions which were performed in 13 patients during the first postoperative year all IMA grafts to the LAD and 11 out of 13 extraanatomical vein grafts were shown to be patent. CONCLUSION: Performance of beating heart extraanatomical coronary artery bypass grafts for management of a heavily diseased ascending aorta can result in a very low stroke rate despite a considerable stroke risk. The complexity of the procedures may be reflected by a relatively high rate of perioperative myocardial infarctions. Perioperative mortality as well as short term patency of extraanatomical bypass grafts seem to be acceptable.

Coronary endothelial injury after local occlusion on the human beating heart.

BACKGROUND: Occlusion of coronary arteries during beating heart surgery bears the potential for mechanical trauma to the arterial wall with consequent endothelial injury. The aim of this study was to elucidate the effects of local occlusion on the beating heart in human coronary arteries. METHODS: Coronary arteries of patients with dilated cardiomyopathy (n = 7) or ischemic heart disease (n = 10) undergoing heart transplantation were locally occluded after starting cardiopulmonary bypass. Immediately after excision of the diseased heart, the vessels were fixed. Unoccluded segments served as controls. Integrity of endothelial lining was observed with scanning electron microscopy. RESULTS: Scanning electron microscopy revealed significantly more severe endothelial injury in the area of occlusion than in the adjacent, not manipulated control segments. In the region of local occlusion, plaque rupture was noted in three of 34 atherosclerotic vessel specimens, injury to side branches was evident in two of 44, and local microthrombus formation was evident in six of 44 samples. CONCLUSIONS: Local occlusion of human coronary arteries during beating heart coronary surgery may cause focal endothelial denudation, local microthrombosis, atherosclerotic plaque rupture, and injury to target vessel side branches.

Inferior vena caval loop of an endocardial pacing lead did not solve the growth problem in a child.

This report describes a transvenous pacemaker lead insertion into a child's right ventricle with a loop formed within the inferior vena cava to allow growth. Five years later emergency revision was necessary because of loss of capture. The expected lead release had not taken place.

Effects of vasopressin and epinephrine on splanchnic blood flow and renal function during and after cardiopulmonary resuscitation in pigs.

OBJECTIVE: To compare the effects of vasopressin versus epinephrine on splanchnic blood flow during and after cardiopulmonary resuscitation (CPR), and to evaluate the effects of these vasopressors on renal function in the postresuscitation phase. DESIGN: Prospective, randomized laboratory investigation using an established porcine CPR model with instrumentation for continuous measurement of splanchnic and renal blood flow. SETTING: University hospital experimental laboratory. SUBJECTS: A total of 12 anesthetized, 12- to 16-wk-old domestic pigs weighing 30-35 kg. INTERVENTIONS: After 4 mins of cardiac arrest, and 3 mins of CPR, 12 pigs were randomly assigned to receive either 0.4 units/kg vasopressin (n = 6) or 45 microg/kg epinephrine (n = 6). Defibrillation was performed 5 mins after drug administration; all animals were observed for 6 hrs after return of spontaneous circulation (ROSC). MEASUREMENTS AND MAIN RESULTS: Mean +/- SEM superior mesenteric artery blood flow was significantly (p < .05) lower after vasopressin compared with epinephrine at 90 secs after drug administration (13+/-3 vs. 129+/-33 mL/min); at 5 mins after drug administration (31+/-18 vs. 155+/-39 mL/min); at 5 mins after ROSC (332+/-47 vs. 1087+/-166 mL/min); and at 15 mins after ROSC (450+/-106 vs. 1130+/-222 mL/min); respectively. Mean +/- SEM left renal and hepatic artery blood flow after ROSC was comparable in both groups ranging between 120-290 mL/min (renal blood flow), and 150-360 mL/min (hepatic blood flow), respectively. Median urine output after ROSC showed no difference between groups, and highest values (180-220 mL/hr) were observed in the first 60 mins after ROSC. Median calculated glomerular filtration rate showed no difference between groups with values ranging between 30 and 80 mL/min in the postresuscitation phase. Calculated fractional sodium excretion and osmolar relationship between urea and plasma indicated no evidence for renal tubular dysfunction. CONCLUSIONS: In the early postresuscitation phase, superior mesenteric blood flow was temporarily impaired by vasopressin in comparison with epinephrine. With respect to renal blood flow and renal function after ROSC, there was no difference between either vasopressor given during CPR. Vasopressin given during CPR did not result in an antidiuretic state in the postresuscitation phase.

Beating heart axillocoronary bypass for management of the untouchable ascending aorta in coronary artery bypass grafting.

OBJECTIVES: Cannulation and clamping of a severely atherosclerotic ascending aorta during coronary artery bypass grafting (CABG) can lead to cerebral embolization of atheromatous debris and should therefore be avoided whenever possible. A variety of surgical techniques including performance of extraanatomical coronary bypass conduits has been described to solve this problem. We report on a preliminary series of four patients in whom the axillary artery was used as an inflow vessel for venous coronary artery bypass grafts which were performed on the beating heart in order to achieve an aortic no touch concept. METHODS: The axillary artery was exposed between the pectoralis major muscle and the deltoid muscle via an infraclavicular incision. A saphenous vein graft of at least 40 cm in length was sutured to the axillary artery and then brought into the pericardial cavity following an intercostal and transpleural route. The graft was anastomosed to the target vessel using local coronary occlusion. The procedure was carried out via sternotomy in three patients who also received additional internal mammary artery in situ grafts for adequate coronary revascularization. In one high risk patient an isolated axillocoronary bypass was performed in a minimally invasive fashion via anterolateral minithoracotomy. RESULTS: The procedure was completed without major technical difficulties in all four patients. The mean graft length required was 33.2 +/- 1.6 cm, postoperative ultrasonic duplex scans of the axillocoronary grafts revealed a mean flow of 62.5 +/- 23.6 ml/min. No stroke or brachial plexus injury occurred. Three patients are in angina class I (Canadian Cardiovascular Society Classification), one patient is in class II postoperatively. After a mean follow-up of 11.5 +/- 6.6 months postoperatively all grafts remain patent. CONCLUSION: Axillocoronary bypass grafting can be easily performed for management of the untouchable ascending aorta. Straightforward surgical technique and the accessibility to noninvasive diagnostics seem to offer advantages over other extraanatomical bypass grafts.

Isolated right ventricular assist for postcardiotomy myocardial infarction.

Due to myocardial infarction, profound postcardiotomy right heart failure developed in a 57-year-old man after implantation of an aortic homograft for infective aortic valve endocarditis. Despite maximum medical therapy and intraaortic balloon counterpulsation, signs of endorgan injury developed, and therefore a Thoratec (Pleasanton, CA) right ventricular assist device was implanted. After 17 days of support, myocardial and endorgan function had recovered and the fully mobilized patient was successfully weaned from support and discharged from the hospital.

Anatomical studies concerning technical feasibility of minimally invasive axillocoronary bypass grafting.

OBJECTIVE: Minimally invasive multiple vessel revascularization has been accomplished using all arterial graft concepts and aortocoronary vein grafts. The aim of the present study was to determine the technical feasibility of minimally invasive axillary artery to coronary artery vein grafting in the human cadaver. METHODS: In seven human cadavers the axillary artery was approached bilaterally via a small incision above the anterior axillary fold. The left anterior descending coronary artery system and the right coronary artery system were exposed via a left anterior minithoracotomy and a subxiphoid incision respectively. Saphenous vein grafts were anastomosed end to side to the axillary artery and brought to the target vessels following a transpleural route. The vein grafts were then sutured to the left anterior descending artery and to the posterior descending artery through the mini-incisions. RESULTS: Axillocoronary bypass grafting to the left anterior descending artery was performed successfully in seven cases, axillocoronary bypass grafting to the posterior descending artery was accomplished in six cases. The mean length of the mini-incisions was as follows: left axillary artery exposure 5.1+/-1.5 cm, right axillary artery exposure 5.5+/-2.0 cm, left anterior minithoracotomy 10.8+/-1.9 cm, subxiphoid incision 9.4+/-1.9 cm. The mean length of saphenous vein required for the left axillary artery to left anterior descending artery bypass was 18.9+/-2.8 cm, the mean length of vein required for the right axillary artery to posterior descending artery bypass was 26.0+/-2.6 cm. This was significantly longer than the aortocoronary route (ascending aorta to left anterior descending artery 12.5+/-2.2 cm P = 0.0001, ascending aorta to posterior descending artery 18.3+/-2.9 cm P < 0.0001). CONCLUSION: From this study we conclude that minimally invasive axillocoronary venous bypass grafting to the left anterior descending artery system and to the distal right coronary artery system is technically feasible in the human cadaver.

Myocardial damage after minimally invasive coronary artery bypass grafting on the beating heart.

BACKGROUND: In conventional coronary artery bypass grafting, the rate of perioperative myocardial infarction is reported in the 2% to 6% range; however, significantly higher rates are observed if sensitive myocardial marker proteins are used to detect perioperative myocardial damage. For minimally invasive direct coronary artery bypass grafting, few data are available concerning myocardial marker protein release. METHODS: Fifteen consecutive patients (11 male, 4 female; mean age, 59.6 +/- 8.5 years) received minimally invasive direct coronary artery bypass grafting procedures via minithoracotomy on the beating heart. Electrocardiography and transesophageal and transthoracic echocardiography as well as determination of creatine kinase-MB mass concentration and cardiac troponin I level were used for ischemic monitoring. RESULTS: One patient had a perioperative myocardial infarction according to standard criteria and died despite mechanical circulatory support. Determination of cardiac troponin I level showed small but definitive ischemic damage in 4 of 9 patients (44%) who presented transient ischemic signs intraoperatively or postoperatively. In 2 of these 4 patients pathologic findings could be detected on angiographic restudies. CONCLUSIONS: Subclinical myocardial injury is a common event in minimally invasive coronary artery bypass grafting on the beating heart. Cardiac troponin I could serve as an adequate diagnostic tool for diagnosis of perioperative myocardial infarction in minimally invasive direct coronary artery bypass grafting.

Intramural right atrial myocardial hemangioma treated by emergency surgery.

An unusual case of myocardial cavernous hemangioma causing dissection of the right atrial wall is described. A subsequent intramural hematoma presented as an extensive pseudotumor of the heart and was complicated by hematopericardium and tamponade. Tumor resection could be performed successfully. Diagnostic approach, surgical treatment and histopathological findings are presented.

[A new cardiac pacemaker stimulation technology (autocapture) allows, with unchanged life expectancy, reduction of generator size by half]. / Eine neue Herzschrittmacher-Stimulationstechnologie (Autocapture) ermöglicht bei unveränderter Lebensdauer die Reduktion der Generatorgrösse auf die Hälfte.

Energy delivery (stimulation amplitude) of a pacemaker should be adjusted to the depolarisation threshold of the heart, which is a nonconstant magnitude. As programming of the stimulation amplitude is time-consuming, many pacemakers are never adjusted to the measured threshold referring to energy delivery. The unnecessary energy loss subsequently reduces the longevity of the implanted devices and remains the weak point of modern pacemakers. Autocapture function (automatic stimulation threshold search, subsequently automatic amplitude regulation 0.3 V above measured threshold, evoked response detection to verify the efficacy of every stimulus and back up pulse in case of loss of capture) is for the first time realized in an extremely small, rate adaptive, multiprogrammable single chamber pacemaker (Microny SR+ 2425T). The pulse generator was tested in a multicentric, european clinical investigation study. These pacemakers were implanted in 8 patients (5 male, 3 female) between December 1994 and April 1995. Automatic measurement of Autocapture threshold revealed 0.7 +/- 0.15 V at implantation, 1.5 +/- 0.3 V after 1 month, 1.3 +/- 0.14 V after 6 months and 1.3 +/- 0.14 V 1 year after implantation. A safety margin of 0.3 V is added to the threshold value to secure capture, therefore mean stimulation amplitude is 1.6 V after 12 months implantation time. The Autocapture feature minimizes current drain and that means that this extremely small generator provides a comparable life as the twice as large common generators used at present time.

Early and late results following coronary bypass surgery beyond the age of 75 years.

The indication for coronary bypass surgery in the elderly has been dramatically expanded in recent years. The results, however, are often contradictory. 1,538 consecutive patients undergoing cardiac surgery were divided into two groups by their age at the time of operation: younger than 75 years (n = 1,480) and 75 years and older (n = 58). These groups were compared with regard to influencing factors of early and late mortality, morbidity, and quality of life. Preoperatively, the clinical condition of the group greater than or equal to 75 years was significantly worse than the condition of the group less than 75 years (NYHA IV: greater than or equal to 75 years: 63.8%; less than 75 years: 31.9%). Cerebrovascular diseases occurred more often in the patients greater than or equal to 75 years (stroke or transient ischemic attack: greater than or equal to 75 years: 8.6%; less than 75 years: 2.3%). The necessity of carotid reconstruction prior to coronary surgery was significantly higher in the patients greater than or equal to 75 years: (greater than or equal to 75 years: 5.2%; less than 75 years: 1.5%). Diabetes mellitus could be observed in 19.0% of the patients greater than or equal to 75 years and in 10.1% of the patients less than 75 years. The preoperative ejection fraction was similar in both groups. Cardiopulmonary bypass time and crossclamping time of the aorta did not differ significantly. Both groups received approximately the same number of distal coronary anastomoses. Rethoracotomy due to hemorrhage had been observed more often in the older group (greater than or equal to 75 years: 8.6%; less than 75 years: 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)