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J J Defauw

Publications and source records attributed to J J Defauw.

At least 19 recordsLinked to original sources
PubMed2003

A randomized study of combining maze surgery for atrial fibrillation with mitral valve surgery.

AIM: Mitral valve surgery seldom suppresses atrial fibrillation (AF), present prior to surgery. Maze III surgery eliminates AF in >80% of cases, the reason why combining this procedure with mitral valve surgery in patients with AF seems worthwhile. We prospectively studied the outcome of combining the Maze III procedure with mitral valve surgery. METHODS: Thirty-five patients with AF and a mean age of 64 years undergoing mitral valve surgery were prospectively randomized according to a 2.5:1 ratio to surgery with (n=25), or without (n=10) maze III and followed for at least 1 year. RESULTS: At discharge and after 12 months freedom from AF was 56% and 92%, respectively, in the maze group, and 0% and 20%, respectively, in patients without maze (group differences at discharge p=0.002, after 12 months p=0.0007). Sinus node incompetence was seen in 1 of 25 maze patients requiring pacing. No in-hospital or late death occurred; stroke was observed in 1 patient (without maze). Quality of life markedly improved after surgery, but did not differ between patients with or without maze surgery. CONCLUSIONS: This first prospective randomized study shows that combining maze III with mitral valve surgery resulted in a significantly better elimination of preoperative AF than mitral valve surgery alone. As the quality of life did not differ between patients with, or without maze surgery, additional maze surgery is primarily recommended in patients in whom anticoagulation therapy can be avoided after surgery, specifically in patients with scheduled mitral valve plasty.

Anti-Arrhythmia Agents↗
PubMed2000

[Reimplantation of aortic valve; preliminary results in 13 patients].

OBJECTIVE: To evaluate our initial experience with the reimplantation technique of the aortic valve. DESIGN: Retrospective. METHOD: From January 1st 1998 to January 31st 2000, 13 patients were operated on by the technique as described by David. Mean age was 52.2 years (SD: 11). Median preoperative New York Heart Association (NYHA) functional class was 2/4 and median preoperative degree of aortic regurgitation was 3/4. Surgical indications were initially limited to aneurysmal disease of the aortic root (n = 6) and ascending aorta (n = 4), all complicated by aortic regurgitation. Later on, we also applied the technique in type A aortic dissection (n = 3). The repair was evaluated peroperatively by transoesophageal and postoperatively, by transthoracic echocardiography. The patients were followed postoperatively in the outpatient department. RESULTS: No technical problems arose that necessitated change or adjustment of the technique. Mean cardiac arrest time was 184 min (SD: 40) and cardiopulmonary bypass time 254 min (SD: 74). The primary aetiology on histopathological examination was medial necrosis in 5 patients and degenerative disease in the others. There was no early nor late mortality and none of the patients was reoperated upon the aortic root. Follow-up was complete at a mean of 12.3 months (SD: 8). Median aortic regurgitation at follow-up was 0.5 (p = 0.0001 versus preoperative) and median NYHA functional class at follow-up was 1 (p = 0.02 versus preoperative). CONCLUSION: David's aortic valve reimplantation technique was carried out with a low surgical risk and a low degree of residual aortic regurgitation in aneurysm of the aortic root, aneurysm of the ascending aorta and type A dissection with major destruction of the aortic root.

Adult↗
PubMed2000

Mitral valve surgery and atrial fibrillation: is atrial fibrillation surgery also needed?

OBJECTIVE: Atrial fibrillation (AF) persisting after mitral valve surgery reduces survival due to heart failure and thrombo-embolisms, and impairs quality of life. Arrhythmia surgery for AF shows today very satisfying results and therefore mitral valve surgery with AF surgery appears appealing. This study explores whether combined surgery in view of today's results of mitral valve surgery is indicated. METHODS AND RESULTS: An outcome analysis of the arrhythmia outcome of patients undergoing exclusive mitral valve surgery with or without tricuspid repair was done. Preoperative baseline characteristics including arrhythmia pattern, surgical methods and follow-up findings were reviewed. Postoperative management of AF was not protocolized. Between 1990 and 1993, 162 consecutive patients underwent mitral valve surgery; follow-up was a mean of 3.3+/-1.9 years. In-hospital and late mortality were 1 and 9%, respectively. Sinus rhythm was preserved in 40 of 57 (70%) patients with preoperative sinus rhythm whereas AF persisted in 58 of 68 (85%) of patients with preoperative chronic AF (>1 year present). Sinus rhythm without AF was observed in 10 of 29 (34%) patients with preoperative paroxysmal AF. The 4-year Kaplan-Meier survival did not differ between patients with preoperative sinus rhythm (95.2%), paroxysmal AF (89.2%) and chronic AF (82.9%) but AF persisting after surgery tended to determine survival (P=0.05). Gender, age and right ventricular pressure and tricuspid valve repair were risk factors for postoperative recurrence of AF in patients with sinus rhythm at discharge, relative risk 0.35, 1.06, 1. 04 and 2.9, respectively. CONCLUSION: Current mitral valve surgery with or without tricuspid valve repair does not eliminate preoperative paroxysmal or chronic AF. Secondly, because preoperative AF did not determine survival after mitral valve surgery, whereas postoperatively persisting AF was weakly associated with survival, atrial arrhythmia surgery primarily aims to reduce morbidity due to AF. Some characteristics can identify patients with increased propensity for persisting AF after surgery. Randomized studies of AF surgery are needed to identify suitable candidates for combined surgery.

Adult↗
PubMed2000

Successful results of a bipolar active fixation lead for atrial application: an interim analysis.

Adequate atrial lead performance consists of stable sensing and pacing properties. To evaluate whether the CPI 4269 bipolar lead, covered with mannitol (Sweet Tip), in the atrial position encounters these properties, we performed a prospective study of this lead. After complete dissolution of the mannitol helix, mapping of the atrium to obtain the highest electrogram and lowest threshold was followed by screw-in into the endocardium. Intraoperative measurements were performed and long-term follow-up was scheduled every 6 to 12 months to measure threshold and perform an intracardial electrogram. Between February 1993 and December 1996, a total number of 73 leads in the atrial position in a consecutive series of patients was implanted. Implantation was performed in 28 patients receiving an AAIR and 45 patients a DDDR pacemaker. Reason for pacemaker implantation was a third-degree AV block in 37% of patients, type II second-degree AV block in 25%, sick sinus syndrome in 35%, and drug refractory paroxysmal atrial fibrillation following His-bundle ablation in 3%. The intraoperative bipolar atrial electrogram had a mean voltage of 4.25 +/- 2.1 mV. The acute atrial bipolar threshold was 0.63 +/- 0.43 V, and current was 1.35 +/- 0.81 mA at a 1.0-ms pulse duration. The mean acute resistance of the lead was 572 +/- 86 Ohm. After a mean follow-up of 18.3 months, the bipolar intracardial electrogram was 3.37 +/- 2.00 mV, the mean atrial threshold measured at the last outpatient clinic visit was 0.99 +/- 0.74 V and the mean impedance was 640 +/- 127 Ohm. A sensing problem due to traction of the atrial lead occurred in only one patient. Acute and late dislodgement did not occur. The CPI 4269 (Sweet Tip) lead is manufactured with a dissolvable capsule covering the helix tip electrode, permitting a safe passage through the venous system. This interim analysis shows that this lead in the atrial position has favorable acute and chronic results.

Adolescent↗
PubMed1999

Cryopreserved aortic allografts for aortic root reconstruction: a single institution's experience.

BACKGROUND: An evaluation of early and long-term results of aortic root replacement with cryopreserved aortic allografts and echocardiographic follow-up of allograft valve function was performed. METHODS: From September 1989 through May 1998, 132 patients aged 17 to 77 years (mean, 50.8 +/- 14.8 years) underwent freestanding aortic root replacement with a cryopreserved aortic allograft. Eighty-six (65.1%) patients had New York Heart Association class III or IV functional status before operation, and 27 (20.5%) patients underwent emergency operation. Fifty-nine (44.7%) patients had undergone previous cardiac operations. The cause of aortic disease was acute endocarditis in 63 (47.7%) patients, healed endocarditis in 15 (11.3%), degenerative in 20 (15.2%), congenital in 20 (15.2%), failed prosthesis in 10 (7.6%) and rheumatic in 4 (3.0%). Follow-up was complete, with a mean of 42 months. RESULTS: There were 12 hospital deaths (9.1%; 70% confidence limits [CL], 6.6% and 11.6%); 9 of them were operated on for active endocarditis (p = 0.062). Multivariate analysis determined age older than 65 years (p = 0.012) and emergency operation (p = 0.009) as independent risk factors for hospital mortality. During follow-up, 6 (5.0%; 70% CL, 3.0% and 7.0%) patients died. Cumulative survival rate for the entire group was 81.8% +/- 5.4% at 8 years. Freedom from reoperation for structural valve failure was 100%, freedom from reoperation for any cause was 96.3% +/- 1.8% at 8 years. Freedom from endocarditis at 8 years was 97.9% +/- 1.4%. Follow-up of allograft valve function showed no or trivial aortic regurgitation in 97% of patients and absence of stenosis of the allograft in 100%. CONCLUSIONS: Aortic root replacement with cryopreserved aortic allografts can be performed with acceptable hospital mortality and long-term results. The durability of cryopreserved aortic allografts is good, and reoperation for structural valve failure is absent at 8 years.

Adolescent↗
PubMed1999

Comparison of late results of surgical or radiofrequency catheter modification of the atrioventricular node for atrioventricular nodal reentrant tachycardia.

AIMS: Although arrhythmia surgery and radiofrequency catheter ablation to cure atrioventricular nodal reentrant tachycardia differ in technical concept, the late results of both methods, in terms of elimination of the arrhythmogenic substrate and procedure-related new and different arrhythmias, have never been compared. This constituted the purpose of this prospective follow-up study. METHODS AND RESULTS: Between 1988 and 1992, 26 patients were surgically treated using perinodal dissection or 'skeletonization', and from 1991 up to 1995, 120 patients underwent radiofrequency modification of the atrioventricular node for atrioventricular nodal reentrant tachycardia. The acute success rates of surgery and radiofrequency catheter ablation were 96% and 92%, respectively. Late recurrence, rate in the surgical and radiofrequency catheter ablation groups was 12% and 17%, respectively. Mean follow-up was 53 months in the surgical group and 28 months in the radiofrequency catheter ablation group. The final success rate after repeat intervention was 100% in the surgical group and 98% in the radiofrequency catheter ablation group. Comparison of the initial and recent series of radiofrequency catheter ablated patients showed an increased initial success rate with fewer applications. In the radiofrequency catheter ablation group, a second- or third-degree block developed in three patients (2%), requiring permanent pacing, whereas in the surgical group no complete atrioventricular block was observed. Inappropriate sinus tachycardia needing drug treatment was observed in 13 patients (11%), mostly after fast pathway ablation, but was never observed after surgery. New and different supraventricular tachyarrhythmias arose in 27% of the patients in the surgical group and in 11% of the radiofrequency catheter ablation group, but did not clearly differ. CONCLUSION: This one-institutional follow-up study demonstrated comparable initial and late success rates as well as incidence of new and different supraventricular arrhythmias following arrhythmia surgery and radiofrequency catheter ablation for atrioventricular nodal reentrant tachycardia. Today radiofrequency catheter ablation has replaced arrhythmia surgery for various reasons, but the late arrhythmic side-effects warrant refinement of technique.

Adult↗
PubMed1998

[Radiofrequency catheter ablation in patients with atrioventricular nodal reentry tachycardia is as effective as rhythm surgery, but less stressful].

OBJECTIVE: To compare the long-term results of surgical modification and of radiofrequency (RF) catheter modification of the atrioventricular node (AV node), to combat recurrent atrioventricular nodal re-entrant tachycardia (AVNRT). DESIGN: Retrospective descriptive. SETTING: St. Antonius Hospital, Nieuwegein, the Netherlands. METHOD: In the period 1988-1992, 26 patients underwent surgical modification and in 1991-1996, 120 patients were subjected to RF catheter modification of the AV node for recurrent AVNRT. The follow-up amounted to at least one year. RESULTS: Surgery was immediately successful in 96%, and RF catheter ablation in 92%. A recurrence AVNRT was seen in 12 and 17% respectively, the ultimate success rates (after retreatment) were 100 and 98%. Three patients (3%) in the RF catheter ablation group developed a second or third-degree AV block necessitating pacemaker implantation. No third-degree AV block was seen in the surgical group. Mean follow-up was 53 months in the surgical group and 28 months in the RF catheter ablation group. Both procedures were accompanied by other supraventricular tachycardias, viz. in 27% of the surgical and in 11% of the RF catheterization ablation group. CONCLUSION: RF catheter ablation for the treatment of AVNRT had early and long-term results comparable with those of rhythm surgery. Since catheter treatment is far less taxing to the patient than rhythm surgery, RF catheter ablation now constitutes the most appropriate method for treatment of this arrhythmia.

Adult↗
PubMed1998

Completion pneumonectomy: analysis of operative mortality and survival.

BACKGROUND: A single-institution experience with completion pneumonectomy was analyzed to assess operative mortality and late outcome. METHODS: A consecutive series of 138 completion pneumonectomies from 1975 to 1995 was reviewed, and compared with single-stage pneumonectomies performed during the same period. RESULTS: Hospital mortality was 13.8%, including 4 intraoperative and 15 postoperative deaths. Hospital mortality was the same for lung cancer (13.2%) as for benign disease (15.5%). It was 37.5% if an early complication of the primary operation was the indication (p = 0.01). If infection of the pleural space was the indication for completion pneumonectomy, hospital mortality was 23.3% (p > 0.05). In 760 single-stage pneumonectomies hospital mortality was 8.7% (p > 0.05). Five-year actuarial survival after completion pneumonectomy was 42.5% for all patients, 32.3% for those with lung cancer, and 58.8% for those with benign disease. CONCLUSIONS: Hospital mortality for completion pneumonectomy was the same for malignant as for benign indications. It was significantly higher if completion pneumonectomy was done for an early complication of the primary operation. Results at long term of lung cancer patients were the same for single-stage pneumonectomy and completion pneumonectomy.

Actuarial Analysis↗
PubMed1997

[Good experiences with an implantable automatic defibrillator with transvenous electrodes for patients with life-threatening arrhythmias].

OBJECTIVE: To describe the results of treatment of patients with a life-threatening arrhythmia by implantation of an second generation implantable cardioverter defibrillator with transvenous electrodes. DESIGN: Descriptive. SETTING: St.-Antonius Hospital, Nieuwegein, the Netherlands. METHOD: In the period October 1991-February 1996 the ICD with transvenous electrodes was implanted in 44 patients. After a year the quality of life was assessed by written questionnaire. RESULTS: The in-hospital mortality was 1/44 (2%), without peroperative death. During follow-up 4 patients died: 3 due to congestive heart failure and 1 due to sudden cardiac death. Within one year 50% of the patients had a therapeutical ICD discharge. In 30/44 (68%) patients antiarrhythmic drugs were prescribed to reduce the number of ICD discharges or because they were suffering from paroxysmal atrial fibrillation with high heart rates, which could result in an inappropriate ICD discharge. Quality of life analysis showed a good acceptance of the ICD, although 86% of the patients considered it a very serious limitation that they were not allowed to drive a motor vehicle anymore. CONCLUSION: The ICD constitutes a major step forward in the treatment of life-threatening ventricular arrhythmias because the implantation is easier and follow-up shows adequate antiarrhythmic effects and survival.

Adult↗
PubMed1997

Allograft aortic root replacement in prosthetic aortic valve endocarditis: a review of 32 patients.

BACKGROUND: This study was conducted to evaluate allograft aortic root replacement in the setting of complicated prosthetic valve endocarditis with extensive annular destruction. METHODS: From January 1990 through March 1996, 32 patients diagnosed with complicated prosthetic valve endocarditis underwent allograft root replacement. Mean age was 58.3 +/- 13.2 years; 23 patients were men. Mean preoperative New York Heart Association functional class was 3.4. Staphylococcus epidermidis (50%) and Enterococcus faecalis (19%) were the predominant causative microorganisms. Annular abscesses were found in 26 patients (81%), aortic-mitral discontinuity in 14 patients (43%), and left ventricular-aortic discontinuity in 11 patients (34%). A cryopreserved allograft was used in 31 patients (97%) and a fresh antibiotic-treated allograft was used in 1 patient (3%). Mean aortic cross-clamp time was 150 +/- 29 minutes. Mean duration of the postoperative antibiotic treatment was 38.5 +/- 11.8 days. RESULTS: There were three operative deaths (9.4%); causes of death were multiorgan failure in 2 patients (6.2%) and low cardiac output in 1 patient (3.2%). Six patients (18%) had complete heart block (4 patients already before the operation), 3 patients (9.4%) had temporary respiratory insufficiency, and 1 patient (3.2%) needed temporary hemodialysis. Mean follow-up was 37.4 +/- 22.4 months. Two late deaths occurred: 1 patient had recurrent endocarditis, leading to a false aneurysm, and died at reoperation; another patient died of lung cancer. Actuarial 5-year survival was 87.3% (70% confidence interval, 76.8% to 97.8%); actuarial 5-year freedom from recurrent endocarditis was 96.5% (70% confidence interval, 90.0% to 100%). CONCLUSIONS: Allograft aortic root replacement is a valuable technique in the complex setting of prosthetic valve endocarditis with involvement of the periannular region. Mortality and morbidity are low.

Abscess↗
PubMed1997

Transsternal closure of bronchopleural fistula after pneumonectomy.

BACKGROUND: Bronchopeural fistula after pneumonectomy, with associated empyema, has no standard therapy. The transsternal, transpericardial approach was used in all patients presenting with a large fistula. METHODS: From 1974 through 1995, 55 patients underwent transsternal, transpericardial closure of a bronchopleural fistula. Mean age was 62.7 years (range, 33 to 78 years). Malignant disease had been the indication for pneumonectomy in 50 patients and benign lesions in 5 patients. The fistula was right-sided in 41 patients (74.5%), and the bronchial stump was less than 2 cm in 25 (45.5%). Treatment of the concomitant empyema was by closed drainage in 2 patients, by repeated needle aspiration in 17, and by open thoracostomy in 36 patients. Reamputation and closure of the stump was possible in 51 patients; in 4 a primary carinal resection was done. RESULTS: Three patients died within 30 days after operation (5.4%, 70% confidence interval 2.4%-10.7%). Ten patients died late during hospitalization, total hospital mortality, 23.6% (70% confidence interval 17.3% to 31.0%). Recurrent fistula symptoms were caused by a large recurrency in 6 patients (all died), by a small one in 7 (one death due to pulmonary embolism). Mean duration of hospital stay was 56 days (range, 2 to 174 days). At follow-up of 42 patients, there were no recurrent fistulas. All patients with benign lesions are alive and well. Of 37 cancer patients, 29 died, more than half due to malignancy. Risk factors for death included recurrent fistula, short interval between pneumonectomy and onset of fistula, and closing technique. Risk factors for recurrent fistula were a short bronchial stump and the nonuse of an open thoracostomy. CONCLUSIONS: Long-term results of transsternal closure are good, but hospital mortality is high. The present treatment of patients with large postpneumonectomy bronchopleural fistula includes early open thoracostomy, improvement of nutritional status, transsternal closure using resorbable sutures, and closure of the pleural space 3 weeks later.

Adult↗
PubMed1997

Long-term follow-up of corridor operation for lone atrial fibrillation: evidence for progression of disease?

INTRODUCTION: Currently, surgery- and catheter-mediated ablation is applied when drug refractoriness of atrial fibrillation is evident, although little is known about the long-term incidence of new atrial arrhythmia and the preservation of sinus node function. METHODS AND RESULTS: To address this issue, 30 patients with successful corridor surgery for lone paroxysmal atrial fibrillation and normal preoperative sinus node function were followed in a single outpatient department. Five years after surgery, the actuarial proportion of patients with recurrence of atrial fibrillation arising in the corridor was 8% +/- 5%, with new atrial arrhythmias consisting of atrial flutter and atrial tachycardia in the corridor 27% +/- 8%, and with incompetent sinus node requiring pacing therapy 13% +/- 6%. Right atrial transport was preserved in 69% of the patients without recurrence of atrial fibrillation and normal sinus node function. Stroke was documented in two patients. CONCLUSIONS: Corridor surgery for atrial fibrillation is a transient or palliative treatment instead of a definitive therapy for drug refractory atrial fibrillation. This observation strongly affects patient selection for this intervention and constitutes a word of caution for other, nonpharmacologic interventions for drug refractory atrial fibrillation.

Adult↗
PubMed1996

Continuation of antiarrhythmic drugs, or arrhythmia surgery after multiple drug failures. A randomized trial in the treatment of postinfarction ventricular tachycardia.

BACKGROUND: In patients with postinfarction sustained ventricular tachycardia showing one or more antiarrhythmic drug failures, the question is how long to proceed with new drug trials before deciding to perform map-guided arrhythmia surgery. Although the techniques of this surgery developed rapidly in the early 1980s, this therapy may be offset by damage to residual left ventricular function. However, surgery has been shown to be very effective in selected groups of patients. METHODS: A randomized study was carried out in patients with postinfarction ventricular tachycardia and eligible for arrhythmia surgery based on residual left ventricular function. Therapy failure was defined by the occurrence of the following events: spontaneous recurrence of ventricular tachycardia or ventricular fibrillation, sudden cardiac death, inducibility of sustained ventricular tachycardia or ventricular fibrillation with programmed stimulation of the heart, symptomatic non-sustained ventricular tachycardia requiring therapy or side-effects of antiarrhythmic drugs requiring withdrawal. In the drug limb, failure of the first antiarrhythmic drug was accepted but failure of a second and different drug was regarded as true therapy failure. RESULTS: After randomization, antiarrhythmic drug therapy was administered in 33 patients, and 30 patients underwent surgery. Neither group differed in baseline characteristics, and the mean number of drug failures before randomization was 2.7. The Kaplan-Meier therapeutic failure of antiarrhythmic drugs was 39 +/- 11%, 42 +/- 11% and 51 +/- 18% at 0.5-, 1- and 4-year follow-up, respectively, whereas the therapeutic failure of cardiac surgery was 37 +/- 11%, 37 +/- 11% and 50 +/- 20% at 0.5, 1 and 4 years, respectively, showing no statistical difference. The 1- and 4-year Kaplan-Meier survival of the antiarrhythmic drug-treated group was 91 +/- 6% and 78 +/- 15%, respectively, and of the surgical group 92 +/- 6% and 59 +/- 20%, respectively, and did not differ between either group. However, the relative risk for total cardiac death was higher in the surgical limb than in the drug limb (relative risk 2.2, CI 0.68-7.48). CONCLUSION: This study demonstrated no difference between the therapeutic result of continuation of two different antiarrhythmic drugs and that of arrhythmia surgery. Despite the small number of patients studied, it is recommended that drug therapy should continue as long as this regimen is tolerated by the patient. When true drug refractoriness or side-effects of drugs arise, arrhythmia surgery offers a valuable alternative. However, when additional reasons for cardiac surgery exist, arrhythmia surgery should be undertaken earlier and may become the first choice of treatment of postinfarction ventricular tachycardia.

Adult↗
PubMed1995

Dispersion of 'refractoriness' in noninfarcted myocardium of patients with ventricular tachycardia or ventricular fibrillation after myocardial infarction.

BACKGROUND: Postinfarction ventricular tachycardias (VTs) may degenerate into ventricular fibrillation (VF), but this does not happen in all patients. The underlying mechanism is not exactly known, but dispersion of refractory periods is considered a major factor in both induction and persistence of reentrant arrhythmias in general. Hypertrophied, noninfarcted myocardium has altered electrophysiological characteristics. We hypothesized that noninfarcted ventricular tissue may provide the heterogeneities that cause the transition from VT into VF. Local fibrillation intervals, ie, the average interval between local activations during VF, have previously been shown to correlate well with local refractoriness in human and canine atrium and in porcine and canine ventricle and may therefore be used as an index of local refractoriness. This technique permits simultaneous assessment of refractoriness at multiple sites. METHODS AND RESULTS: We measured local fibrillation intervals at 32 to 64 sites in the noninfarcted part of the left ventricle in patients undergoing antiarrhythmic surgery for symptomatic, drug-refractory, postinfarction ventricular tachyarrhythmias. The grid of electrodes (interelectrode distance, 7 mm) was attached to the epicardium of the left ventricle remote from the infarcted tissue. Group 1 consisted of 7 patients with hemodynamically tolerable sustained VT (VT group). Group 2 consisted of 7 patients with cardiac arrest and documented VF (VF group). With the patients on cardiopulmonary bypass, VF was induced by multiple premature stimulation. The VF interval was not significantly different in the two study groups (VT group, 136 +/- 5.5 ms; VF group, 129 +/- 3.4 ms, mean +/- SEM). However, spatial dispersion of the VF intervals (remote from the infarcted area) expressed as the coefficient of variation of VF intervals (SD x 100/mean VF interval in each heart) was significantly larger in the VF group. It was 3.63 +/- 0.56 in the VF group and 1.55 +/- 0.40 in the VT group (mean +/- SEM; P < .01). Differences between the shortest and longest VF intervals in one and the same heart and the largest difference between two adjacent sites were also larger in the VF group (P < .02 and P < .05, respectively). CONCLUSIONS: This study shows larger dispersion in VF intervals and therefore suggests larger dispersion of refractory periods in parts of the myocardium remote from the infarction in patients with postinfarction VF than in patients with postinfarction VT.

Aged↗
PubMed1995

Use of left heart bypass in the surgical repair of thoracoabdominal aortic aneurysms.

The purpose of this study was to assess the usefulness of left heart bypass in thoracoabdominal aortic aneurysm surgery. Data from 50 patients who underwent thoracoabdominal aortic aneurysm repair between July 1987 and October 1993 were retrospectively reviewed. In all of them a left heart bypass (left atrium to left femoral artery) with a centrifugal pump (without systemic heparinization) was used. Patient-, disease-, and operation-related variables were analyzed using univariate methods. There were no intraoperative deaths. The in-hospital mortality rate was 8% (n = 4). Survival rates were 77% (+/- 6.5) at 2 years and 62% (+/- 8.7) at 5 years. Renal failure requiring dialysis occurred in five (10%) patients and paraplegia in five (10%). Sixteen (32%) patients had respiratory insufficiency requiring prolonged (> 8 days) ventilation. After univariate analysis, the risk factors for developing a need for postoperative dialysis were found to be the preoperative creatinine level (p = 0.002) and the presence of preoperative arterial hypertension (p = 0.018). A history of peripheral vascular occlusive disease (p = 0.008) was an important risk factor for predicting late death. No factors retained significance in the univariate analysis of hospital deaths and postoperative paraplegia. Renal and spinal ischemic times were substantially reduced in comparison to the theoretic times calculated if cross-clamping had been used. Bypass-related complications were completely absent. The use of a left heart bypass during thoracoabdominal aortic aneurysm surgery may not reduce the global complication rate; the results were similar to those achieved using simple cross-clamping. However, this technique appears to be the method of choice for protecting organ systems at risk during difficult repairs.

Aged↗
PubMed1994

Slow potentials in the atrioventricular junctional area of patients operated on for atrioventricular node tachycardias and in isolated porcine hearts.

OBJECTIVES: The purpose of this study was to 1) investigate extracellular electrograms in the atrioventricular (AV) junctional area of patients with AV node reentrant tachycardia, 2) compare them with recordings made in isolated porcine hearts, and 3) study their origin. BACKGROUND: Electrograms with slow components have been used to target the delivery of radiofrequency energy for the cure of AV node reentrant tachycardia. The origin of these electrograms is unknown. METHODS: In 12 human and 19 porcine hearts, extracellular recordings were made simultaneously from 64 sites. In five other porcine hearts, intracellular recordings were made at sites at which extracellular electrograms revealed slow potentials. Histologic investigations were carried out in four of these hearts. RESULTS: Electrograms with slow components were recorded in five human and eight porcine hearts. These signals were found at sites up to 12 mm from the His bundle. Characteristics of the electrograms did not differ significantly among human and porcine hearts. Electrophysiologic evidence for multiple pathways was present in four hearts. Superficial impalements with microelectrodes at sites with slow potentials showed action potentials with AV node characteristics. In the majority of these recordings, the upstroke coincided with the downstroke of slow potentials. Histologic investigations of the sites of impalement revealed transitional cells directly underneath the endocardium. CONCLUSIONS: Slow potentials were recorded in both human and porcine hearts in similar measure. They arise from transitional cells and have action potentials similar to N cells.

Animals↗
PubMed1994

Single-leg strut fractures in explanted Björk-Shiley valves.

A retrospective follow-up study in the Netherlands on the risk of fracture of Björk-Shiley convexo-concave valves concluded that prophylactic replacement is advisable for certain groups of patients. We have examined valves explanted from twenty-two patients because they met epidemiological criteria for reoperation, with or without the presence of moderate cardiac impairment, or because there were other cardiac complaints not related to the valve. No information was available before explanation to suggest a valve defect. All patients survived their operations. Of the twenty-four valves, seven (29% [95% CI 13-52]) had fracture of one of the legs of the outlet strut (single-leg strut fracture [SLF]). Two other valves had features that suggested fatigue defects. As in the previous study, 70 degrees valves had the highest risk of SLF (five of sixteen, two aortic and three mitral). However, two of eight 60 degrees valves (both aortic) also had SLF. Current hazard calculations and explanation recommendations may need to be revised. Since several of the defective valves were welded by the same person, knowledge of manufacturing details may help in estimation of fracture risk for an individual patient.

Adult↗