Transposition of greater omentum in deep sternal wound infection caused by methicillin-resistant Staphylococci, with differing clinical course for MRSA and MRSE.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MRSE) are an increasing problem in deep sternal wound infections (DSWI) after cardiac surgery. METHODS: Between 2005 and 2009, recalcitrant methicillin-resistant Staphylococcus was found in 21 patients with complicated DSWI, and a transposition of the greater omentum (TGO) was finally performed. A positive microbial culture at the time of procedure was present in all patients. The hospital course was reviewed discretely for MRSA and MRSE. RESULTS: Median patient age was 72.3 years (range 60.8-79.7); 76 % of patients were male. Time from the first sternal revision until consecutive open wound therapy due to re-infection and total hospital stay was longer for MRSA compared to MRSE (38 vs. 14 days, P = 0.003, and 141 vs. 91 days, P = 0.007, respectively). The period from cardiac surgery to TGO was likewise prolonged for MRSA (78 vs. 55 days, P = 0.045), whereas in-hospital mortality and one-year mortality rate did not differ. CONCLUSION: TGO remains a good treatment option for DSWI type IV. Microbial findings determine the clinical course; nevertheless in-hospital mortality remains low for both MRSA and MRSE infection.

Chronic heart failure induced by multiple sequential coronary microembolization in sheep.

OBJECTIVE: Although a large variety of animal models for acute ischemia and acute heart failure exist, valuable models for studies on the effect of ventricular assist devices in chronic heart failure are scarce. We aimed to establish a stable and reproducible animal model of chronic heart failure in sheep. METHODS: Sheep (n=8, 77 +/- 4 kg) were anesthesized and a 5F sheath was implanted into the left carotid artery. The left main coronary artery was catheterized under flouroscopic guidance and bolus injection of polysterol microspheres (90 microm, n=25.000) was performed. Microembolization (ME) was repeated up to three times in two to three week intervals until animals started to develop stable clinical signs of heart failure. Clinical and echocardiographic data were analyzed at baseline (base) and at three months (3 mo) after first ME. All animals were followed for 3 months after first microembolization and then sacrificed for histological examination. Another four healthy sheep (79+/-6 kg) served as control animals. RESULTS: All animals developed clinical signs of heart failure as indicated by increased heart rate at rest (68+/-4 bpm (base) to 93 +/- 5 bpm (3 mo) (p<0.05)), increased respiratory rate at rest (28+/-5 (base) to 38 +/- 7 (3 mo) (p<0.05)) and increased body weight 77 +/- 2 kg to 81 +/- 2 kg (p<0.05) due to pleural effusion, peripheral edema and ascites. Echocardiographic evaluation revealed significantly an increase of left ventricular enddiastolic diameter from 46 +/- 3 mm (base) to 61 +/- 4 mm (3 mo) (p<0.05). Clinically and echocardiographically no significant changes were revealed in healthy control animals. CONCLUSIONS: We conclude that multiple sequential intracoronary microembolization can effectively induce myocardial dysfunction with clinical and echocardiographical signs of chronic ischemic cardiomyopathy. The present model may be suitable in experimental work on heart failure and left ventricular assist devices, e.g. for studying the impact of mechanical unloading, mechanisms of recovery and reverse remodeling.

Periodontal bacteria DNA findings in human cardiac tissue - Is there a link of periodontitis to heart valve disease?

BACKGROUND: The aim of the study was to detect periodontal pathogens DNA in atrial and myocardial tissue, and to investigate periodontal status and their connection to cardiac tissue inflammation. METHODS: In 30 patients, biopsy samples were taken from the atrium (A) and the ventricle myocardium (M) during aortic valve surgery. The dental examination included the dental and periodontal status (PS) and a collection of a microbiological sample. The detection of 11 periodontal pathogens DNA in oral and heart samples was carried out using PCR. The heart samples were prepared for detecting the LPS-binding protein (LBP), and for inflammation scoring on immunohistochemistry (IHC), comprising macrophages (CD68), LPS-binding protein receptor (CD14), and LBP (big42). RESULTS: 28 (93%) patients showed moderate to severe periodontitis. The periodontal pathogens in the oral samples of all patients revealed a similar distribution (3-93%). To a lesser extent and with a different distribution, these bacteria DNA were also detected in atrium and myocardium (3-27%). The LBP was detected in higher amount in atrium (0.22±0.16) versus myocardium (0.13±0.13, p=0.001). IHC showed a higher inflammation score in atrial than myocardial tissue as well as for CD14, CD68 and for LBP. Additional, periodontal findings showed a significant correlation to CD14 and CD68. CONCLUSION: The results provide evidence of the occurrence of oral bacteria DNA at the cardiac tissue, with a different impact on atrial and myocardial tissue inflammation. Influence of periodontal findings was identified, but their relevance is not yet distinct. Therefore further clinical investigations with long term implication are warranted.

[Anomaly of the vena cava inferior with paracaval venous aneurysm and renal collateralisation]. / Achsenanomalien der Vena cava inferior mit paracavalem venösen Aneurysma und renalem Kollateralkreislauf.

Aneurysms of the great venous vessels represent anatomical rarities. Most malformations of the venous system published so far concern mainly the inferior vena cava and arise in different formations. Reports of malformations of the renal veins are limited to a few case reports and may lead to diagnostic and therapeutic difficulties. We report on an case of a asymptomatic, aneurysmatic venous malformation of the vena cava inferior With consideration of the entire findings we preferred a conservative treatment of the patient.

The effects of residual pump blood on patient plasma free haemoglobin levels post cardiac surgery.

At the end of cardiopulmonary bypass, there are invariably several hundred millilitres of residual pump blood in the reservoir, which can either be re-transfused or discarded. The objective of this prospective observational study was to investigate the quality of the residual pump blood, focusing on plasma free haemoglobin (pfHb) and blood cell counts. Fifty-one consecutive patients were included in the study. Forty-nine units of residual pump blood and 58 units of transfused red blood cell (RBC) concentrates were analysed. The mean preoperative pfHb of the patients was 0.057 ± 0.062 g/l, which increased gradually to 0.55 ± 0.36 g/l on arrival in the intensive care unit postoperatively. On the first postoperative day, the mean pfHb had returned to within the normal range. Our data showed that haemoglobin, haematocrit, and erythrocyte counts of residual pump blood were approximately 40% of the values in standardised RBC concentrates. Plasma free haemoglobin was significantly higher in residual pump blood compared to RBC concentrates, and nearly twice as high as the pfHb in patient blood samples taken contemporaneously. Our findings indicate that residual pump blood pfHb levels are markedly higher compared to patients' blood and RBC concentrates, but that its administration does not significantly increase patients' pfHb levels.

Quantitative assessment of the operative results after extended myectomy and surgical reconstruction of the subvalvular mitral apparatus in hypertrophic obstructive cardiomyopathy using dynamic three-dimensional transesophageal echocardiography.

OBJECTIVES: The aim of this study was to examine the value of dynamic three-dimensional (3D) transesophageal echocardiography (TEE) for the postoperative evaluation after extended myectomy and surgical reconstruction of the subvalvular mitral valve apparatus in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Two-dimensional imaging techniques such as echocardiography, computed tomography and magnetic resonance imaging have not been able to precisely quantify the effects of surgical therapy on the morphology of the left ventricular outflow tract (LVOT). METHODS: Multiplane TEE with 3D reconstruction was performed in 11 patients before and after the operation and in 16 normal control subjects for comparison. The preoperative maximal systolic pressure gradient in the LVOT was 69 +/- 59 mm Hg. The following variables were measured within the dynamic 3D data set: depth, width, length and cross-sectional area (CSA) gain caused by the myectomy trough, minimal CSA of the LVOT at each time point and its cyclic changes and maximal mitral leaflet deviation during systole. RESULTS: Functional class improved from 3.0 +/- 0.2 before the operation to 1.5 +/- 0.6 after it. The maximal systolic pressure gradient in the outflow tract decreased to 26 +/- 21 mm Hg postoperatively (p < 0.001). Minimal CSA of the outflow tract increased from 1.1 +/- 1.2 to 3.8 +/- 1.9 cm2 postoperatively (p < 0.001), similar to the value of the control group (4.2 +/- 1.5 cm2, p = NS). The area gain due to the myectomy trough was 1.3 +/- 1.0 cm2, corresponding to 48 +/- 12% of the total operative area difference. Maximal systolic depth of the myectomy was 7 +/- 2 mm, maximal width was 20 +/- 8 mm and length was 28 +/- 7 mm. Maximal deviation of the mitral leaflets fell from 15 +/- 7 to 6 +/- 7 mm postoperatively (p < 0.01). In five patients mass measurements of the intracavitary portion of the papillary muscle (PM) revealed an increase from 7.3 +/- 1.0 to 12.1 +/- 2.5 g due to surgical mobilization of PMs (p < 0.01). CONCLUSIONS: 3D TEE quantifies the differences in outflow tract morphology before and after surgery for HOCM. This technique may have an impact on the planning of operative interventions and allow for the evaluation of its results.

Potential benefit of biventricular pacing in patients with congestive heart failure and ventricular tachyarrhythmia.

Treatment of congestive heart failure (CHF) aims for symptomatic relief and reduction of mortality both from sudden death and pump failure. The implantable cardioverter defibrillator (ICD) is highly effective in the prevention of sudden death, but no mortality benefit in advanced CHF has yet been shown. Biventricular pacing may lead to functional improvement in selected patients with CHF. Thus, a biventricular pacemaker with defibrillation capabilities may be ideal for patients with advanced CHF. We retrospectively analyzed the data from 384 patients (age 59 +/- 12 years, 322 male and 62 female) with regard to New York Heart Association (NYHA) CHF class, mean QRS duration, mean PR interval, presence of a QRS > 120 msec and incidence of atrial fibrillation at the time of ICD implantation. Based on eligibility criteria from studies in biventricular pacing, we analyzed how many patients may benefit from biventricular pacing. Patients with CHF were older (NYHA class III: 60.9 +/- 9.7, class II: 61.3 +/- 10 versus class I: 50.8 +/- 13.6 years, p < 0.001 each) and mean QRS duration was longer with advanced CHF (NYHA class III 127.8 +/- 30 msec; class II 119.4 +/- 27.7 msec; class 0-1: 103.9 +/- 17.7 msec, p < 0.001, analysis of variance) as was the mean PR interval (NYHA class III 189.9 +/- 33.5 msec; class II 176.1 +/- 29.3 msec; class 0-1 162.7 +/- 45.9 msec, p < 0.001, analysis of variance). The incidence of atrial fibrillation was higher in class III (25.5%) compared with class 0-1 (16.9%) and class II patients (14.1%, p = 0.043, chi-square test). A total of 28 patients (7.3%) fulfilled eligibility criteria for biventricular pacing if NYHA class III patients were considered candidates and 48 (12.5%) if patients with NYHA II CHF and ejection fraction < or = 30% were included. Thus, biventricular pacing may offer a promising therapeutic approach for a significant proportion of patients with CHF at risk for ventricular tachyarrhythmia.

Does multiplane transesophageal echocardiography improve the assessment of prosthetic valve regurgitation?

Assessment of prosthetic valve regurgitation by echocardiography remains difficult. To study the value of the newly introduced multiplane transesophageal technology for this purpose, prosthetic valve regurgitation was examined in 63 consecutive patients with 35 mitral and 33 aortic prostheses (23 bioprostheses and 45 mechanical prostheses). Transvalvular, paravalvular and, in mechanical valves, normal or pathologic transvalvular regurgitation were identified first with 0 degrees (transverse) and 90 degrees (longitudinal) planes combined with flexion of the echoscope tip and then additionally with multiple intermediary planes by transducer rotation. In a subgroup of 20 patients interobserver variability was evaluated. Both methods showed regurgitation in 56 of 68 valves; one additional case of regurgitation was seen by multiplane imaging only. However, 19 cases of regurgitation were not clearly classifiable by biplane transesophageal echocardiography compared with only three with multiplane transesophageal echocardiography. Grading of severity was concordant by both modalities in 66 and discordant in only two cases. Observers disagreed on severity in two of 20 cases based on biplane imaging but in none based on multiplane imaging; classification of regurgitation differed in six of 20 (biplane) and one of 20 (multiplane), respectively. Multiplane transesophageal imaging improves classification of prosthetic regurgitation but has little effect on severity grading.

Prophylactic reoperation for strut fractures of the Björk-Shiley convexo-concave heart valve.

Outlet strut fracture of the Björk-Shiley Convexo-Concave (C/C) heart valve is the current paradigm of structural failure of mechanical heart valve prostheses. The estimated risk of fracture for C/C valves varies from 0.02% to 2.5% per patient-year, depending on valve size, opening angle, date of manufacture and position as a mitral or aortic replacement. This report examines our experience with 396 implants, comprising 346 C/C 60 degrees valves and 50 C/C 70 degrees valves. The 30-day mortality was 1.8%. Through April 1993, mean follow up was 8.9 years, incorporating 2971 patient-years and knowledge of the current status of 91.5% (356/389) of operative survivors. Late mortality was 3.7% per patient-year, including one 60 degrees and one 70 degrees outlet strut fracture. To evaluate the risk of semi-elective valve re-replacement at our institution, we reviewed the results of isolated re-replacements of failing or incipiently failing bioprostheses in 65 patients who had no serious co-morbidity and who were NYHA Class III or lower immediately before the procedure. The 30-day mortality was 4.6% and the overall serious morbidity rate was 10.8%, necessitating six repeat reoperations. When these factors were balanced against the life expectancy and general status of five patients with large-size, higher-fracture-risk 70 degrees C/C valves, it was concluded that only two patients remained possible reoperation candidates. Consideration for re-replacement of a normally functioning C/C heart valve should take into account institution-specific experience because structural failure remains a low risk compared to valve-related complications engendered by reoperation.

Twenty years experience with pediatric pacing: epicardial and transvenous stimulation.

OBJECTIVE: Permanent cardiac pacing in children and adolescents is rare and often occurs by means of epicardial pacing. Based on two decades of experience, operative and postoperative data of patients with epicardial and transvenous pacing were analyzed retrospectively. METHODS: Between October 1979 and December 1998, 71 patients (mean age, 5.3+/-4.2, range, 1 day-16.2 years; mean body weight, 18+/-12; range, 8-56 kg) underwent permanent pacemaker implantation. Indications were sinus node dysfunction and atrio-ventricular block following surgery for congenital heart disease (69%), or congenital atrioventricular block (31%). Pacing was purely atrial (1.4%), purely ventricular (73%), ventricular with atrial synchronization (5. 6%), or atrioventricular synchronized (20%). Epicardial pacing was established in 49 (69%), transvenous in 22 (31%) patients. Follow-up was 3.4+/-3.8 years (epicardial) and 3.0+/-4.0 years (transvenous). RESULTS: Epicardial leads were implanted in younger patients (mean age: 4.5 vs. 7.0 years, P<0.05) and preferably after surgery induced atrioventricular block (78 vs. 46%, P<0.05). The youngest patient with transvenous pacing was 1.3 years old (weight, 8.5 kg). At implantation epicardial ventricular stimulation threshold at 1.0 ms was 1.07+/-0.46 vs. 0.53+/-0.31 V (transvenous) (P<0.05). The age-adjusted rate of lead-related reoperations was significantly higher in patients with epicardial leads (P<0.05), mainly due to increasing chronic stimulation thresholds resulting in early battery depletion. In three patients who received steroid-eluting epicardial leads initial low thresholds persisted after five month to one years. In two patients with recurrent epicardial threshold increase, steroid-eluting epicardial leads led to good acute and chronic thresholds after nine to 15 month. Two post-operative death (2.8%) were probably due to a dysfunction of the (epicardial) pacing system. CONCLUSIONS: Transvenous pacing in the pediatric population is associated with a lower acute stimulation threshold and a lower rate of lead-related complications. If epicardial pacing is necessary (e. g. small body weight, special intracardiac anatomy (e.g. Fontan), impossible access to superior caval vein), steroid-eluting leads may be considered.

[Josef Koncz (1916-1988)--pioneer of cardiac surgery]. / Josef Koncz (1916-1988)--Pionier der Herzchirurgie.

Josef Koncz (1916-1988) was until given emeritus status in 1982 director of the Department of Cardiothoracic and Vascular Surgery, which was specifically founded for him in Goettingen, Germany. By the fusion of three different surgical branches the University hospital of Goettingen took over the role of a pacemaker and initiated a standard in the development of this new specialty in Germany. The scientific and clinical work done by the Department of Cardiothoracic and Vascular Surgery was shaped by the personality of the surgeon and scientist Josef Koncz. He was a successful surgeon and innovative pioneer in one person. Already in 1956, he started open-heart surgery and proceeded this technique in an impressing series. In 1965 he was the first in Germany who operated upon the transposition of the great vessels by Mustard's method and developed together with his long-standing assistant, Huschang Rastan, an operation technique to extend the left-ventricular outflow tract combined with tunnel-shaped subvalvular aortic valve stenosis. Another essential element of his work is related to the establishment of the Cardiothoracic and Vascular Surgery as an independent specialty, ending in the foundation of the German Society for Thoracic and Cardiovascular Surgery in 1971.

Surgical management of vascular graft infection in severely ill patients by partial resection of the infected prosthesis.

INTRODUCTION: In the presented retrospective study, we report on our results with partial resection of infected prosthetic grafts after aorto-bifemoral graft placement in eight male and three female patients. METHODS: In all 11 patients clinical signs of infection were observed and bacteriological cultures were positive. Three patients underwent immediate surgery for perforation of an aneurysm at the distal anastomosis, eight patients underwent elective surgery. In all cases silver-coated Dacron prostheses were implanted. Assessment of outcome was based on survival, limb salvage, persistent or recurrent infection, and prosthetic graft patency. RESULTS: In two cases, a partial wound dehiscence occurred which was treated with ambulant Vacuseal dressings for 16 and 21 days until secondary wound healing was achieved. In eight patients systemic markers of inflammation completed normalised within nine days. Follow-up CT-scans failed to demonstrate any signs of recurrent infection or peri-graft fluid collections. Patients were treated with specific antibiotic therapy for no more than three months. Post-operative bacteriological cultures were negative in all patients. The mean follow-up was 2.5+/-0.5 yrs. During follow-up, none of the patients died and there were no amputations. CONCLUSION: Despite only partial resection of the infected prostheses, the reported surgical procedure offers good results. This approach maybe particularly suitable for the treatment of elderly patients with prosthesis infections.

Extended myectomy for hypertrophic obstructive cardiomyopathy after failure or contraindication of septal ablation or with combined surgical procedures.

BACKGROUND: Surgical correction of hypertrophic obstructive cardiomyopathy in severely symptomatic patients has been proven to be effective over the long term. The introduction of catheter-based procedures restricts surgical therapy to a subset of patients not suitable for septal ablation or requiring concomitant cardiac surgery. METHODS: Between 8/2001 and 8/2003, 25 patients (58 +/- 15 years) underwent extended transaortic septal myectomy with partial excision and mobilization of the papillary muscles. Concomitant surgical procedures were performed in 40 % (CABG n = 9, aortic valve replacement n = 2). In 24 %, prior septal ablation was ineffective. Intraventricular gradient was 80 +/- 29 mm Hg at rest and 143 +/- 35 mm Hg during exercise. Mitral regurgitation affected 72 % of patients, and 88 % were NYHA functional class III or IV. RESULTS: No hospital death, no postsurgical ventricular septal defect, and no complete atrioventricular block occurred. Severe nonfatal complications occurred in 24 % of patients. Intensive care was necessary for 1.8 +/- 1.7 days; total hospital stay was 11.8 +/- 3.8 days. Early follow-up was complete in 100 % (15 +/- 6 months, total of 376 months) with no late deaths, no relevant mitral regurgitation, or intraventricular gradients. Functional status was markedly improved (NYHA class I 40 %, class II 56 %, class III 4 %). CONCLUSIONS: Early results of extended surgical myectomy and reconstruction of the subvalvular mitral apparatus in hypertrophic obstructive cardiomyopathy remain excellent with respect to mortality, morbidity, and functional capacity even when restricting surgery to patients earlier supposed to be at high risk.

Optimized pulse durations minimize the effect of polarity reversal on defibrillation efficacy with biphasic shocks.

There are conflicting results on the effect of polarity change on the defibrillation efficacy of biphasic shocks possibly caused by different shock durations. The goal of the present study was to investigate the influence of polarity reversal on defibrillation efficacy for different biphasic shock durations in a porcine animal model. In eight anesthesized pigs using a transvenous/submuscular lead system DFTs for 4 phase 1 durations were determined: 8.1 ms, 6 ms, 3.8 ms and 1.7 ms. The phase 1/phase 2 ratio was constant at 60%/40%. For cathodal shocks, the defibrillation coil in the right ventricular apex was the cathode during phase 1 and for anodal shocks it was the anode. For both polarities, the strength-duration curve revealed a DFT minimum at 3.8 ms (cathodal shocks: 21.3 +/- 6.4 J, P < 0.001; anodal shocks: 21.9 +/- 8 J, P = 0.05). For anodal shocks and phase 1 durations of 1.7, 3.8, and 6 ms there was no significant difference of the stored energy at the DFT compared to cathodal shocks. In contrast, significantly lower DFTs were observed for anodal shocks with a phase 1 duration of 8.1 ms (28.8 +/- 6.4 J compared to 33.1 +/- 5.9 J for cathodal shocks, P = 0.006). The effect of lower defibrillation energy requirements with polarity reversal depends on the total biphasic shock duration; for the pulse duration with the lowest DFT, polarity reversal does not increase defibrillation efficacy of biphasic shocks.

Rapid appearance of severe mitral regurgitation under high-dosage corticosteroid therapy in a patient with systemic lupus erythematosus.

Survival of patients with systemic lupus erythematosus has increased with corticosteroid therapy. However, adverse effects of corticosteroid therapy on cardiovascular structures, such as scarring and shrinking of affected valves, are not well known. We report the case of a 19-year-old patient who developed severe mitral insufficiency within a few weeks after high-dosage corticosteroid therapy had been instituted for an acute relapse of systemic lupus erythematosus. The rapid development of severe mitral regurgitation was documented by sequential colour Doppler echocardiography.

Procalcitonin is a valuable prognostic marker in cardiac surgery but not specific for infection.

BACKGROUND: The prognostic value of elevated serum levels of procalcitonin (PCT) in patients early after cardiac surgery on cardiopulmonary bypass (CPB) remains unclear. In a prospective study, we investigated whether PCT is useful as a prognostic marker in cardiac surgery with respect to mortality, complications and infections, and whether PCT is a specific marker for occurrence of infections. METHODS: Within 8 months, a subset of 80 high-risk patients (APACHE II-score: 25.1 +/- 4.7 (mean +/- SD)) out of a consecutive cohort of 776 patients was investigated. Demographic data, operative data and clinical endpoints (mortality, infection, severe complication) were documented. Serum levels of PCT were analyzed preoperatively and at postoperative day 1. RESULTS: Hospital mortality in this high-risk group was 21.3 %, infections occurred in 33.8 % and complications in 58.8 % of the patients. Preoperative PCT was normal in all patients. Postoperative PCT was increased in non-survivors compared to survivors (34.3 +/- 7.0 ng/ml vs. 15.9 +/- 4.9 ng/ml; p < 0.05), in patients with severe complications (30.3 +/- 6.7 ng/ml vs. 5.5 +/- 1.4 ng/ml; p < 0.05) and in patients with infections (38.4 +/- 11.3 ng/ml vs. 10.8 +/- 1.6 ng/ml; p < 0.05). Area under receiver operating characteristic curve for PCT as predictor of mortality, infections and complications was 0.772 (95 %-confidence-interval (CI): 0.651 - 0.894), 0.720 (95 %-CI: 0.603 - 0.837) and 0.861 (95 %-CI: 0.779 - 0.943), respectively. PCT was not different with infectious compared to non-infectious complications. CONCLUSIONS: High levels of PCT are associated with mortality, infections, and severe complications early after cardiac surgery using cardiopulmonary bypass and therefore provide a valuable prognostic marker. However, PCT does not discriminate between infectious and non-infectious complications.

[Improved evaluation of prosthetic heart valve regurgitation with multiplanar transesophageal echocardiography]. / Bessere Beurteilung von Klappenprotheseninsuffizienzen mit der multiplanen transösophagealen Echokardiographie.

UNLABELLED: To study the value of the newly introduced multiplane transesophageal transducer technology for the assessment of prosthetic valve regurgitation, 63 consecutive patients with 35 mitral and 33 aortic prostheses (23 bioprostheses and 45 mechanical prostheses) were examined. Transvalvular, paravalvular, and, in mechanical valves, normal or pathological transvalvular regurgitation were identified using first 0 degrees (transverse) and 90 degrees (longitudinal) planes combined with flexion of the echoscope tip and then additionally using multiple intermediary planes by transducer rotation. In a subgroup of 20 patients interobserver variability was evaluated. Both methods showed regurgitation in 56/58 valves; one additional case of regurgitation was seen by multiplane imaging only. However, there were 19 cases of regurgitation not clearly classifiable by biplane technique compared to only three using multiplane technique. Grading of severity was concordant by both modalities in 66 and discordant in only two cases. Observers disagreed on severity in 2/20 cases based on biplane imaging, but in none based on multiplane imaging; classification of regurgitation differed in 6/20 biplane and 1/20 multiplane images respectively. CONCLUSION: Multiplane transesophageal imaging improves classification of prosthetic regurgitation, but has little effect on severity grading.

Polarity reversal improves defibrillation efficacy in patients undergoing transvenous cardioverter defibrillator implantation with biphasic shocks.

The purpose of this study was to determine the influence of polarity reversal on DFT in patients undergoing implantation of nonthoracotomy defibrillators with biphasic shocks. Previous studies have shown higher defibrillation efficacy with using the distal electrode as anode implantation of nonthoracotomy defibrillators and monophasic shocks. However, it is as yet unclear whether biphasic shock defibrillation will also be influenced by polarity reversal. Using a transvenous lead system with a proximal electrode in the superior caval vein and a distal electrode in the RV apex, 27 patients undergoing defibrillator implantation were randomized to DFT testing "initial" (distal electrode = cathode) or "reversed" polarity (distal electrode = anode). Defibrillation energy was reduced stepwise until defibrillation failure occurred. At this point, polarity was switched and testing continued until the lowest energy requirement was determined for both polarities. With reversed polarity, DFT was 11.1 +/- 5.7 J versus 13.3 +/- 5.8 J with polarity (P = 0.033). This means a 17% reduction of the DFT. In 10 patients, the threshold was lower with reversed, whereas in 3 patients it was lower with initial polarity. In conclusion, changing electrode polarity in transvenous implantable defibrillators with biphasic shocks may significantly influence defibrillation energy requirements. Therefore, polarity reversal should always be attempted before considering patch implantation.

Effect of biphasic shock duration on defibrillation threshold with different electrode configurations and phase 2 capacitances: prediction by upper-limit-of-vulnerability determination.

BACKGROUND: The defibrillation threshold (DFT) may be affected by biphasic shock duration (BSD), electrode configuration, and capacitance. The upper limit of vulnerability (ULV) may be used to estimate the DFT. For different lead configurations and phase 2 capacitances, we investigated in 18 pigs whether the use of ULV may predict waveforms with lowest DFT. METHODS AND RESULTS: -DFT and ULV were determined by up-down protocols for 10 BSDs. ULVs were measured by T-wave scanning during ventricular pacing (cycle length 500 ms). In protocol 1 (n=6), a pectoral "active can" was combined with an electrode in the superior vena cava as common cathode and a right ventricle electrode as anode (AC+SVC). In protocol 2 and protocol 3 (n=6 each), only the "active can" was used as proximal electrode (AC). Capacitance was 150 microF during both phases in protocol 1 and protocol 3 but 150 microF (phase 1) and 300 microF (phase 2) in protocol 2. ULV and DFT demonstrated a linear correlation in each protocol (r=0.78 to 0.84). Lowest DFTs were found at 10 ms for AC+SVC and at 14 ms for AC (P<0.001). At optimal BSDs, voltage DFTs did not differ significantly between AC (527+/-57 V) and AC+SVC (520+/-70 V). Switching capacitors for phase 2 in a way that reduced leading-edge voltage by 50% while doubling capacity did not change BSD for optimal voltage DFT but increased minimum DFT from 527+/-57 V to 653+/-133 V (P=0.04). CONCLUSIONS: The BSD with lowest DFT is shorter for AC+SVC than for AC. There is no significant difference in voltage DFT between both at optimal BSD. A lower phase 2 capacitance reduces DFTs irrespective of BSD. Because strength-duration curves for DFT and ULV correlate for different BSDs, lead systems, and phase 2 capacitances, ULV determination may allow the prediction of waveforms with lowest DFT.