Combined spontaneous contralateral pneumothorax and post-pneumonectomy mediastinal shift-associated dextrocardia.

We report here on an unusual late postoperative presentation of extreme post-pneumonectomy dextrocardia and spontaneous contralateral pneumothorax presenting as late complications occurring approximately 2 years after right-sided pneumonectomy. Computed tomography is the diagnostic modality of choice to obtain information on anatomical changes within the post-pneumonectomy space. Knowledge of the spectrum of cardiopulmonary, pleural, and other complications after lung resection is important to properly manage complications in post-pneumonectomy patients.

Right ventricular fibroma in a 61-year-old man.

We report on a 61-year-old man who presented with new negative T-waves in V3 to V5. Coronary heart disease with a nonsignificant stenosis of the anterior interventricular artery was known for three years without any symptoms of heart failure. Harvested endomyocardial biopsies of the left ventricle during catheterization showed a chronic parvovirus B19-associated myocarditis. A magnetic resonance imaging was carried out and showed a 6 x 3 x 3-cm mass in the right ventricle extending from the apex. The tumor could be completely resected using cardiopulmonary bypass. Histopathological diagnosis was consistent with a benign fibroma.

Comparison of magnetic resonance imaging and transthoracic echocardiography for the identification of LV mass and volume regression indices 6 months after mitral valve repair.

BACKGROUND: Magnetic Resonance Imaging (MRI) and transthoracic echocardiography have been shown to be noninvasive highly sensitive diagnostic tools to identify changes in LV mass and volume. We therefore investigated the effects of mitral valve repair (MVR) on LV function parameters including ejection fraction (EF; %), indices of LV mass (LVMI; g/m2) and volume (LVEDVI, LVESVI; mL/m2) as detected by MRI and echocardiography. METHODS: Eight consecutive patients (mean age 53.3 +/- 10.0 years) with severe mitral regurgitation (MR; grade III-IV), normal LV function and sinus rhythm were included in this prospective study. Cine MRI and transthoracic M-mode echocardiography were performed pre-operatively, as well as 6 months post-op, to identify changes in EF and in LV mass and volume. Data are given as mean +/- standard deviation. RESULTS: Post-op MR was grade 0-I in all patients. Early mortality and late mortality was 0%. EF by either method did not change significantly within the follow-up period. A significant improvement of indices of LV mass and volume was detected by Cine MRI and echocardiography within 6 months following surgery (LVMIMRI: pre-op: 76.3 +/- 20.1 vs. post-op: 66.5 +/- 14.3, p < 0.05; LVMIEcho: pre-op: 184.2 +/- 38.1 vs. post-op: 136.5 +/- 28.4, p < 0.05. LVEDVIMRI: pre-op: 119.3 +/- 26.0 vs. post-op: 75.4 +/- 13.1, p < 0.05; LVEDVIEcho: pre-op: 97.4 +/- 28.8 vs. post-op: 69.2 +/- 13.1, p < 0.05. LVESVIMRI: pre-op: 44.6 +/- 12.0 vs. post-op: 32.5 +/- 9.5, p < 0.05; LVESVIEcho: pre-op: 29.3 +/- 8.3 vs. post-op: 21.8 +/- 4.6, p < 0.05). CONCLUSIONS: MRI and echocardiography show a significant reduction of LV volume and mass 6 months after MVR. The data show that for routine follow-up transthoracic M-mode echocardiography provides reliable information for the identification of LV mass and volume regression in patients after MVR.

Optimal port placement and enhanced guidance in robotically assisted cardiac surgery.

BACKGROUND: Optimal port placement and enhanced guidance in robotically assisted cardiac surgery is required to improve preoperative planning and intraoperative navigation. METHODS: Offline optimal port placement is planned on a three-dimensional virtual reconstruction of the patient's computed tomography scan. Using this data, an accurate in vivo port placement can be performed, which is achieved by augmented reality techniques superimposing virtual models of the thorax and the teleoperator arms on top of the real worldview. RESULTS: A new system incorporating both port placement planning and intraoperative navigation in robotically assisted minimally invasive heart surgery was established to aid the operative workflow. A significant reduction of operation time by improved planning and intraoperative support is anticipated. CONCLUSIONS: The enhanced intraoperative orientation possibilities may lead to further decrease in operation time and have the continuing ability to improve quality.

C1-INH and its effect on infarct size and ventricular function in an acute pig model of infarction, cardiopulmonary bypass, and reperfusion.

BACKGROUND: Recent studies suggest that complement inhibition reduces reperfusion injury. A clinical setting with local application of a C1 esterase inhibitor (C1-INH) has been modeled in an animal study in order to further investigate these findings. METHODS: In 21 pigs, the left anterior descending coronary artery (LAD) was occluded distally to the first diagonal branch for 2 hours (h), including 1 h of cardioplegic arrest during CPB. After release of the coronary snare, C1-INH or NaCl (control) was applied to the aortic root. Thereafter, the aortic cross-clamp was removed and the heart was reperfused for 30 minutes before weaning from CPB. Left ventricular pressure volume analysis was performed by a multielectrode conductance catheter and the area at risk and infarct size were determined from excised hearts. RESULTS: The following data were observed (mean+/-SEM) for the control group and the C1-INH group, respectively, after 1-h ligation of the LAD: heart rate (HR) 86+/-3 and 93+/-6 beats/min, stroke volume (SV) 1.2+/-0.1 and 1.2+/-0.1 ml/kg, aortic pressure (AoP) 83+/-6 and 87+/-5 mmHg, left ventricular end-diastolic pressure (LVedP) 12+/-1 and 11+/-2 mmHg; two hours after weaning from CPB: HR 106+/-9 and 123+/-4 beats/min, SV 0.9+/-0.1 and 0.9+/-0.1 ml/kg, AoP 65+/-5 and 79+/-7 mmHg, LVedP 9+/-1 and 8+/-1 mmHg. Conductance catheter measurements showed no improved left ventricular performance after C1-INH application. Infarct size to area at risk ratio was 61.5+/-4.2% for controls and 61.4+/-4.8% for C1-INH. CONCLUSIONS: Intracoronary application of complement inhibitor in an acute infarction model, which mimicked a clinical setting of urgent coronary bypass grafting after ischemia, has been shown to neither influence the area of infarction, nor the ventricular function.

Diastolic unloading and improved LV pump efficiency early after repair of the insufficient mitral valve.

BACKGROUND: This study aimed to evaluate the acute effect of mitral valve repair (MVR) on LV hemodynamics and geometry in patients with normal ventricular function. METHODS: In 10 patients with severe mitral regurgitation undergoing MVR, pressure-volume relationships were recorded before annuloplasty prior to and after hemodilution and after MVR during stable circulatory condition, using the conductance catheter technique (CC). Analyses were done off-line; volume calibration was based on data obtained after completion of valve repair (mean +/- s.d.). RESULTS: CC showed that only 61 +/- 15 % of left ventricular output was ejected into the systemic circulation, regurgitation volume being 39 +/- 15 %. MVR led to a reduction in LV stroke work index from 4.7 +/- 1.8 mm Hg x l x m (-2) at before valve repair to 2.2 +/- 1.0 mm Hg x l x m (-2) after surgery at unchanged cardiac index. LV diastolic filling parameters improved: LV relaxation time constant tau decreased from 52 +/- 15 to 37 +/- 11 ms and dP/dt (min) increased from - 873 +/- 231 to - 1286 +/- 283 mm Hg x s (-1). CONCLUSIONS: Despite cardioplegic arrest, MVR leads to acute improvement of diastolic LV function early after the operation. This may explain why valve repair has an acute positive effect in patients with impaired LV function.

Towards robotic heart surgery: introduction of autonomous procedures into an experimental surgical telemanipulator system.

The introduction of telemanipulator systems into cardiac surgery enabled the heart surgeon to perform minimally invasive procedures with high precision and stereoscopic view. For further improvement and especially for inclusion of autonomous action sequences, implementation of force-feedback is necessary. The aim of our study was to provide a robotic scenario giving the surgeon an impression very similar to open procedures (high immersion) and to enable autonomous surgical knot tying with delicate suture material. In this experimental set-up the feasibility of autonomous surgical knot tying is demonstrated for the first time using stereoscopic view and force feedback.

Impairment of cardiovascular autonomic control in patients early after cardiac surgery.

OBJECTIVE: Impairment of the baroreceptor reflex activity reflects an alteration of the autonomous regulation of the cardiovascular system and has proven to predict fatal outcome in patients after acute myocardial infarction. The following study was performed to analyse the baroreceptor sensitivity, heart rate variability and blood pressure variability in patients early after coronary surgery. METHODS: Twenty-five male patients undergoing coronary artery bypass were examined in a prospective study; normal values were obtained from healthy volunteers. Arterial pressure signals were recorded from a radial artery catheter for 30 min preoperatively and in short intervals after surgery. Mechanical manipulations and pharmacological interventions were avoided during the sampling periods. Baroreflex function was calculated according to the dual sequence method, heart rate variability and blood pressure variability were calculated including nonlinear methods. RESULTS: Initial values of the patients did not differ from healthy volunteers. The strength of baroreflex sensitivity (increase in blood pressure causing a synchronous decrease of heart rate) is low 2 h postoperatively. The number of delayed tachycardic changes of heart rate, which are caused by sympathetic activation, is only moderately reduced as compared to values obtained from healthy volunteers. Heart rate variability is widely unchanged as compared to preoperative values; blood pressure variability showed an increase of low-frequency components, again indicating sympathetic predominance. Nonlinear analyses revealed reduced system complexity at the beginning of the postoperative course. CONCLUSION: Obviously, there is a vagal suppression 20 h after surgery, while the sympathetic tonus works in a normal range. This unbalanced interaction of the autonomous systems is similar to findings in patients after myocardial infarction. The predictive value of these markers has to be elucidated in further clinical studies.

[Analysis of cardiovascular regulation after heart operation]. / Analyse der kardiovaskulären Regulation nach Herzoperation.

Baroreflex sensitivity, heart rate and blood pressure variability have been proven to predict fatal outcome in patients after acute myocardial infarction. This study aims at investigating the time dependent alterations in cardiovascular control to find new predictive parameters for arrhythmic events after surgery. 25 male patients with coronary heart disease following an aortocoronary bypass surgery were examined. The results show significant alterations in sympathetic and vagal mediated regulation. The extubation after 6 hours seems to influence primarily the sympathetic activation. Obviously, there is a vagal suppression 20 h after surgery, while the sympathetic tonus works in a normal range. This unbalanced interaction of the autonomous system seems to be a reason for the high incidence of atrial tachycardias in the early period after cardiac surgery.

Effect of C1-esterase-inhibitor on capillary leak and inflammatory response syndrome during arterial switch operations in neonates.

OBJECTIVE: To determine if prophylactic administration of C1-esterase-inhibitor would have a beneficial effect on postoperative weight gain and the inflammatory response in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). DESIGN: Randomized, double-blinded study. SETTING: University-affiliated heart center. PARTICIPANTS: Twenty-four neonates with transposition of the great arteries. INTERVENTIONS: In group inhibitor (INH) patients (n = 12), 100 IU/kg of C1-esterase-inhibitor (Berinert) was given 30 minutes before CPB. In group placebo (P) patients (n = 12), placebo was administered instead. Interleukin (IL)-6, C3a anaphylatoxin, C1 activity, prekallikrein, Hageman factor, D-dimers, and clinical parameters were measured 6 times perioperatively. MEASUREMENTS AND MAIN RESULTS: All 24 patients had an uneventful clinical course. Mean arterial pressure and pulmonary oxygenation after CPB were superior in group INH patients. The weight gain on postoperative days 1 to 4 was significantly less in group INH patients compared with group P (55 +/- 59 g vs. 340 +/- 121 g, day 1). The concentration of IL-6 (76 +/- 17 pg/mL vs. 262 +/- 95 pg/mL during CPB) was significantly lower in group INH patients compared with group P patients. In contrast, no influence on C3a anaphylatoxin and coagulation factors was found. CONCLUSION: Prophylactic application of C1-esterase-inhibitor in neonates undergoing arterial switch operations produces less inflammatory response compared with placebo. This difference may have contributed to improved clinical parameters, including less weight gain postoperatively.

Pectoral implantation of single-lead implantable cardioverter-defibrillators in patients without transvenous access.

With the introduction of the single-lead "Active-Can" implantable cardioverter-defibrillators, the implantation of the internal defibrillators has become a technically easy procedure. With these systems lowest defibrillation thresholds are achieved with a very low complication rate. For patients with thrombosis of both subclavian veins, however, a transvenous implantation technique is not possible. These patients are still equipped with epicardial patch electrodes. This article describes an alternative technique for implantation of this system in such patients, eliminating the need for epicardial patches and related complications.

Aortic input impedance and ventriculoarterial coupling following cardioversion/defibrillation.

Defibrillation shocks are commonly used after cardiac surgery or during defibrillator implantation. The hemodynamic consequences of countershocks on circulatory dynamics are not completely understood, and there is a lack of information concerning the effects on ventriculoarterial interaction. The study presented here was performed to assess the influence of defibrillation shocks on arterial hemodynamics and ventriculoarterial coupling. Eight mongrel dogs (weight 15-18 kg) were anesthetized and median thoracotomy was performed. Pressure in the ascending aorta and the left ventricle and flow in the ascending aorta were continuously monitored. After induction of atrial or ventricular fibrillation, termination was achieved by epicardial low energy shocks (atrium, 3J; ventricle, 51). In an additional attempt ventricular fibrillation was terminated by a high energy shock (34J). Aortic input impedance was calculated by fast-Fourier-transformation of aortic flow and pressure signals, while ventriculoarterial coupling was expressed by the ratio of aortic and ventricular end systolic elastance (Ea/Ees). Defibrillation by low energy shocks of atrial or ventricular fibrillation did not result in changes of the aortic impedance spectrum, and ventriculoarterial coupling remained unaltered compared to control conditions. High energy defibrillation, however, resulted in a marked rise in total peripheral resistance (P < 0.03). The ratio of Ea/Ees increased significantly (P < 0.005). These effects were reversible within 15 minutes. Low energy defibrillation does not alter arterial hemodynamics and ventriculoarterial coupling in this experimental setup. High energy defibrillation, however, results in a temporary increase of ventricular load. This finding may be of particular interest in patients with poor left ventricular function.

[A new concept for treatment of supraventricular tachycardia after heart operations: low energy internal cardioversion using a temporary atrial electrode]. / Ein neues Konzept zur Behandlung von supraventrikulären Tachykardien nach Herzoperationen: Niederenergetische interne Kardioversion über eine temporäre atriale Elektrode.

Supraventricular tachycardia (SVT) is a common complication early after cardiac surgery. A novel temporary atrial patch electrode (TAPE) for low energy atrial defibrillation was first implanted for intraoperative testing and subsequently removed during open heart surgery in 10 patients (Phase I). After the intraoperative testing period, the TAPE was implanted in 20 patients for postoperative termination of spontaneous episodes of supraventricular tachycardia (Phase II). In case of supraventricular tachycardia (SVT), biphasic shocks (1.2-5.0 J) were applied, measuring the atrial defibrillation thresholds. Phase I: The mean intraoperative atrial defibrillation threshold was 1.6 +/- 1.4 J with a mean shock-impedance of 64.0 +/- 7.3 Ohms. Phase II: Postoperatively, 6 out of 20 patients (30%) developed 7 episodes of atrial fibrillation (n = 6) and atrial flutter (n = 1). In 5 patients, SVT could be converted to sinus rhythm (n = 5) or junctional rhythm (n = 1). The mean postoperative defibrillation threshold (DFT) was 2.7 +/- 2.1 J with a mean shock-impedance of 50.2 +/- 6.8 Ohms. In conclusion, the TAPE allows low-energy defibrillation of atrial fibrillation. It seems to be a useful alternative in the treatment of supraventricular tachycardia.

Simulation of arterial hemodynamics after partial prosthetic replacement of the aorta.

BACKGROUND: Replacing parts of the aorta with a non-compliant vascular prosthesis results in marked alterations of the aortic input impedance and influences arterial hemodynamics. We propose a mathematical model of circulation that can predict hemodynamic changes after simulation of vascular grafting. METHODS: A new mathematical model of the human arterial system was developed on a 75-MHz Pentium personal computer using Matlab software. The human arterial tree was delineated according to a 128-branch design encompassing bifurcations and physical properties of the arterial wall. A digitized aortic flow wave was chosen as the input signal to the system. After determination of the modules of elasticity of native vascular tissue and standard prostheses in technical experiments, replacement of any part of the aorta with a prosthesis was simulated by increasing the elasticity in the parts desired. RESULTS: During control conditions, the model displayed a physiologic distribution of flow and pressure waves throughout the arterial system. Simulated replacement of the aorta resulted in an increase in pressure amplitude and a partial loss of the aortic "Windkessel" function. Calculation of the aortic input impedance showed an increase in the characteristic impedance, whereas the peripheral resistance remained unaltered. CONCLUSIONS: This mathematical model of the arterial circulation is useful for simulating hemodynamic changes after implantation of vascular grafts. The results of the model analysis are consistent with those in previous experimental work.

Adjustable atrial and ventricular temporary electrode for low-energy termination of tachyarrhythmias early after cardiac surgery.

Supraventricular and ventricular tachycardias are common and serious postoperative complications early after cardiac surgery. We introduce a completely removable temporary adjustable defibrillation electrode (TADE) for low energy cardioversion/defibrillation of postoperative atrial and ventricular tachyarrhythmias. The electrode consists of three loops of steel wires connected to one steel wire, which are movable within an isolation sheet for adjusting the active surface to the individual size of the heart chambers. Evaluation of the electrode was performed in 10 open-chest beagles with a mean weight of 25.5 kg. The electrodes were first positioned on the left and right atrium. Atrial fibrillation (AF) was induced via a bipolar temporary heart wire. Atrial defibrillation thresholds (DFTs) were measured according to a step-down shock protocol (5-0.4 J). Thereafter, the electrodes were adjusted and positioned on the right and left ventricle. Ventricular fibrillation (VF) was induced and DFTs were recorded the same way. Aortic flow and pressure and left ventricular pressure were continuously monitored throughout the experiment. For termination of AF, mean DFTs were 0.4 +/- 0 J (lowest possible shock level) with a mean shock impedance of 70 +/- 7.6 ohms. VF was terminated with a mean DFT of 3 +/- 1.1 J with a mean impedance 56.1 +/- 7.9 ohms. Complete transcutaneous removal of the electrodes was possible in all animals without any complications. In conclusion, successful low energy termination of AF and VF is possible with the tested temporary adjustable electrode. A clinical study is planned for further evaluation.

[Temporary adjustable defibrillator electrodes: an alternative method for the treatment of postoperative arrhythmias after heart surgery]. / Temporäre anpassbare Defibrillationselektrode: Ein alternatives Verfahren zur Behandlung von postoperativen Rhythmusstörungen nach Herzoperationen.

INTRODUCTION: Supraventricular and ventricular tachycardias are common and serious postoperative complications early after cardiac surgery. We introduce a new temporary adjustable defibrillation electrode (TADE) for internal low-energy cardioversion/defibrillation of postoperative atrial and ventricular tachyarrhythmias. METHODS: Evaluation of the new electrode was performed in ten open-chest beagles with a mean weight of 25.5 kg. The electrodes were first positioned on the left and right atrium. Atrial fibrillation (AU) was induced via a bipolar temporary heart wire. Atrial defibrillation thresholds (DFT's) were measured according to a step-down shock protocol (5 J-0.4 J). Thereafter, the electrodes were adjusted and positioned on the right and left ventricle. Ventricular fibrillation (VF) was induced and DFT's were recorded the same way. RESULTS: For termination of AF, mean DFT's were 0.4 +/- 0 J (lowest possible shock level) with a mean shock impedance of 70 +/- 7.6 omega. VF was terminated with a mean DFT of 3 +/- 1.1 J with a mean impedance 56.1 +/- 7.9 omega. Complete transcutaneous removal of the electrodes was possible in all animals without any complications. CONCLUSION: Successful low-energy termination of AF and VF is possible with the tested temporary adjustable electrode. A clinical study is planned for further evaluation.

Rescue therapy with C1-esterase inhibitor concentrate after emergency coronary surgery for failed PTCA.

Administration of C1-esterase inhibitor (C1-INH) attenuates myocardial necrosis and sustains normal cardiac performance after myocardial ischemia and reperfusion in animal experiments. We report on our first experience of C1-INH application as rescue therapy in patients undergoing emergency surgical revascularization after failed percutaneous transluminal coronary angioplasty. Three patients were treated, because post-operative hemodynamic stabilization could not be achieved despite prolonged reperfusion periods, high-dose inotropic support, inodilators and aortic counterpulsation. As there was no surgical or medical option remaining, C1-INH was administered starting with a 2000 unit bolus, followed by 1000 U 12 and 24 h after surgery. C1-INH therapy resulted in rapid hemodynamic stabilization of all patients; weaning from aortic counterpulsation and epinephrine support was possible within 1 day. All patients survived and were discharged from hospital. In this group of patients suffering from severe reperfusion injury after coronary surgery, C1-INH seemed to be an effective adjuvant therapy to restore myocardial function by blocking the complement cascade. These results should encourage the performance of controlled studies on the effects of prophylactic C1-INH substitution therapy in patients undergoing coronary surgery at high risk conditions.

[Surgery of acute aortic valve endocarditis: prognosis in paravalvular abscess]. / Chirurgie der akuten Aortenklappenendokarditis: Prognose bei paravalvulären Abszessen.

The occurrence of paravalvular abscesses in the course of an acute endocarditis of the aortic valve indicates an advanced stadium of the disease. The infection has spread beyond the limits of the valve leaflets, and ongoing destruction of the paravalvular tissue is to be expected, if the endocarditis is continually treated by antibiotics alone. Surgery of acute endocarditis with paravalvular abscess, however, supposedly carries an increased risk of early mortality and late morbidity. The following prospective study was carried out to determine whether a radical surgical approach together with aggressive postoperative antibiotic therapy could help to improve results. Between 1988 and 1995, 138 patients were operated during the acute phase of infective endocarditis; in 102 the aortic valve was involved. Among these, 44 had paravalvular abscesses at the time of surgery. The mean age of both groups was the same, but there was a higher rate of concomitant coronary artery disease, multiple valve involvement, advanced NYHA-class, and staphylococcal disease among the patients with abscesses. All interventions were carried out with cardiopulmonary bypass and cardioplegic arrest. The aortic valve was resected, abscesses were removed, and each part of potentially infected or necrotic tissue was resected as complete as possible, irrespective of the possibility to jeopardize the conduction system or to create large tissue defects. The aortic valve was replaced with a mechanical prosthesis in each case. The postoperative antibiotic regimen was specifically directed against the microorganisms isolated preoperatively; therapy was only modified, if signs of systemic infection did not disappear three days after surgery. The operative mortality was 10% among patients without an abscess and 11% in patients with a paravalvular abscess. Early recurrent endocarditis was recorded in two patients without and in only one patient with an abscess. Late recurrent endocarditis was noted in three patients; none of them had abscesses at the time of surgery. We conclude that the operative risk of acute endocarditis of the aortic valve with a paravalvular abscess does not have to be inevitably higher compared to cases without paravalvular involvement. To achieve these results, it is necessary to use a radical surgical approach and to adjust postoperative antibiotic therapy, if infectious signs do not disappear shortly after surgery.