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Biomedical subjects

J Ostermeyer

Publications and source records attributed to J Ostermeyer.

At least 37 records · Page 2Linked to original sources
PubMed1991

The arterial switch-operation: early and midterm (6 years) results with particular reference to technical problems.

Since February 1985 the arterial switch operation (ASO) has become the surgical treatment of choice for newborns with simple TGA, appropriate forms of complex TGA and double outlet right ventricle (DORV) as well at our institution. Between 1985 and 1990 a total of 87 patients underwent surgery. In 60 patients with simple TGA and 8 patients with complex TGA or DORV, respectively, an arterial switch-operation was performed. Because of coronary artery anomalies (n = 13), dysplastic pulmonary valves (n = 3) or pressure drop in the left ventricle (n = 1), the initially planned arterial switch operation was discarded and a Mustard type procedure was in 17 patient. Finally there were two primarily performed Mustard operations. The hospital mortality after arterial switch for simple TGA was 15% (9/60), 0/8 in patients with complex TGA. Late mortality was calculated to be 12% (1/8) in patients with complex TGA and 3/60 in patients with simple TGA. Within the Mustard group there were 2/19 hospital deaths and one late death. Causes of early death after arterial switch were: intraoperative myocardial infarct (n = 3) low cardiac output syndrome (n = 2), intractable bleeding (n = 2), metabolic acidosis (n = 1), and septicemia (n = 1). Late after surgery there was one death due to chylothorax after thrombotic obstruction of the SVC, and 3 more deaths secondary to intraoperative infarct, progressive LV dysfunction and meningitis, respectively. Among the long-term survivors 2 patients developed a severe supravalvulary pulmonary stenosis. There were no significant arrhythmias, supravalvulary pulmonary aortic stenoses, aortic insufficiency or myocardial perfusion disturbances.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1990

Relation between ventricular late endocardial activity during intraoperative endocardial mapping and low-amplitude signals within the terminal QRS complex on the signal-averaged surface electrocardiogram.

Noninvasive recording of ventricular late potentials and intraoperative endocardial mapping at 36 sites were performed in 24 patients with left ventricular aneurysm and drug-resistant sustained ventricular tachycardia due to coronary artery disease. Their mean age was 55 +/- 8 years. Mean ejection fraction was 28 +/- 12%. For detection of late potentials on the signal-averaged QRS complex, 3 different algorithms were used. Late potentials were found in 54, 67 and 67% of the patients, respectively. In patients with a late potential on the signal-averaged electrocardiogram (ECG), delayed local activation (greater than 40 ms beyond the QRS complex on the intraoperative surface ECG) was recorded at 5.5, 5.5 and 5.6 endocardial sites. In patients without a late potential, this type of delayed local activation was detected at 2.4, 1.1 and 0.9 of 36 endocardial sites, respectively (p less than 0.05; p less than 0.01; p less than 0.002). The mean delay of local endocardial activity was 38, 35 and 37 ms in patients with a late potential on the body surface recording versus 20, 19 and 11 ms, respectively, in patients without a late potential (p less than 0.05; p less than 0.05; p less than 0.002). There was no correlation between the duration or amplitude of the late potential, if present, and the number of endocardial sites exhibiting delayed activity (r = -0.23, r = -0.05, r = 0.21; correlation not significant for each) or the mean duration of the endocardial delayed activity (r = -0.25, r = -0.14, r = -0.07; correlation not significant for each). These results indicate that the presence of late potentials on the signal-averaged surface ECG is related to the mean duration of endocardial late activity as well as to the number of endocardial sites exhibiting a given degree of delayed activation. Thus, it is dependent on the mass of slowly activated tissue. However, a direct conclusion from the duration or the amplitude of a late potential to the amount of delayed activation or the extent of endocardial time delay does not seem possible.

Algorithms↗
PubMed1990

[Anti-tachycardia surgery in ventricular arrhythmia].

UNLABELLED: Recurrent sustained ventricular tachycardia (VT) is associated predominantly with ischemic heart disease, mostly in the chronic phase after myocardial infarction. Potentially life-threatening and drug-refractory ventricular tachycardias are called malignant VT. In the Federal Republic of Germany, VT develops in about 3,000 to 5,000 patients per year from the 100,000 who survive a myocardial infarction. About 10% of these patients prove to be medically-refractory or additionally are considered candidates for aneurysmectomy or coronary revascularization. Overall, for the Federal Republic of Germany, there is a need for approximately 500 to 1000 antitachycardia operations each year. The morphologic substrate for malignant VT are ischemically-damaged inhomogeneously-structured arrhythmogenic areas. The morphology results in electrical inhomogeneity which predisposes to electrophysiologic reentry phenomena. NATURAL HISTORY: The survival rate of patients with malignant VT who are not surgically treated is 70% at one year and 20 to 40% at four years (Figure 1). In those in whom the tachycardia can be medically controlled, the prognosis is 10.5 times more favorable than in those with medically-refractory arrhythmias. In one study of 45 patients with recurrent, sustained VT, only 20% of those with medical refractoriness were free of renewed arrhythmic events after 30 weeks as compared to 90% whose treatment had been designated effective (p less than 0.0004) (Figure 2). According to a further study, for patients with drug-refractory VT, the probability for sudden death within four years was 55% as compared with 5% for those with medically-controlled VT (p less than 0.0002). SURGICAL TREATMENT: The concept of surgical treatment of malignant VT encompasses delineation of the arrhythmogenic area by means of endocardial mapping and surgical ablation. Arrhythmogenic areas are located mostly in the transition zone between the viable muscle and an aneurysm at the left ventricular endomyocardial septum. With mapping, by means of local measurements of activity times, impulse spread throughout the heart can be recorded in a cartographic system. The left ventricular endocardial activation should be determined during sinus rhythm and tachycardia and, with normothermic extracorporeal circulation the left ventricle is incised, mostly in the aneurysmatic antero-apical area, prior to sequential interrogation of the endocardial surface (Figure 3). As an alternative to point-for-point mapping, by means of multi-terminal electrodes, electrocardiograms can be obtained simultaneously from multiple positions. During tachycardia, the earliest activation can be found in the arrhythmogenic area (Figure 4); during sinus rhythm, in these areas, delayed, low-amplitude and fragmented signals are present (Figure 5). Macroscopically, endomyocardial fibrosis is a common finding. The arrhythmogenic morphologic substrate is either reduced or rendered a homogeneous scar without electrical activity. In this regard, techniques for endomyocardial resection have been described by Harken and Josephson. As an alternative procedure. Guiraudon introduced the encircling endomyocardial resection with which the pathologic reentry circuit can be blocked and the microvascular blood flow to arrhythmogenic areas eliminated. One modification, the partial encircling resection, appears to yield comparable effectiveness with less damage to left ventricular function (Figure 6).(ABSTRACT TRUNCATED AT 400 WORDS)

Electrocardiography↗
PubMed1989

Ten years electrophysiologically guided direct operations for malignant ischemic ventricular tachycardia--results.

UNLABELLED: During the recent 10 years period worldwide more than 1000 patients underwent an electrophysiologically guided direct operation for malignant ventricular tachycardia in the setting of chronic ischemic heart disease. The published results of these operations as regards relief of ventricular tachycardia and survival are highly variable. The data presented here are largely based on a multi-institutional registry series (n = 665) and the combined Düsseldorf-Birmingham/Alabama (DUS-UAB) ventricular tachycardia surgery experience (n = 216). DATA: Survival (hospital deaths included) was 75% one year after operation and 45% at 5 years (DUS-UAB). The respective data of the registry series were 78% and 55%. The most prevalent mode of death in both analyses was acute/subacute/chronic heart failure. More extensive encircling procedures (incisional/cryo) for ventricular tachycardia ablation and the combination of encircling cryoablation and endocardial resection increased the risk of progressive left ventricular dysfunction and death; however, by multivariate analysis the severity of the underlying ischemic heart disease (indicated by NYHA functional class, LVEDP, No. of previous infarcts, and extensiveness of coronary disease) and the absence of a discrete left ventricular aneurysm were more powerful predictors for early and late postoperative mortality than the use of alternative surgical techniques for ventricular tachycardia ablation. Survival was particularly poor after the return of spontaneous sustained ventricular tachycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1989

[Heart arrhythmia following surgery of congenital heart defects].

As a result of the intraoperative trauma sinus node dysfunction and AV conduction defects have been observed. In addition bifascicular block (RBBB with LAH) may occur after repair of a ventricular septal defect. This electrocardiographic pattern indicates a high risk of developing a trifascicular block only in those patients with reversible AV block in the early postoperative period. After closure of an atrial septal defect, atrial fibrillation can develop as well as ventricular tachycardia and fibrillation after repair of a ventricular septal defect. The latter seems to be the underlying mechanism of sudden cardiac death occurring late after operation, especially in patients with Fallot tetralogy. In addition to the scar, persistent structural myocardial changes seem to be an important factor. Electrophysiological investigation is indicated in all symptomatic patients especially for detection and treatment of ventricular tachyarrhythmias. However, there is yet no proof that sudden death can be prevented by antiarrhythmic treatment of all ventricular premature beats in the endangered patients.

Arrhythmias, Cardiac↗
PubMed1988

Value of post-operative programmed ventricular stimulation after map-guided surgery for ventricular tachyarrhythmias--epicardial versus endocardial stimulation.

To assess the efficacy of map-guided antitachycardia surgery, induction of ventricular tachycardia has mostly been performed using endocardial stimulation. In addition, epicardial stimulation can be done using temporary epicardial wires, thus not requiring post-operative catheterization. However, the diagnostic value of epicardial versus endocardial stimulation for the post-operative evaluation of patients undergoing map-guided surgery for drug-refractory ventricular tachycardia is not known, especially with regard to the induction of non-clinical tachyarrhythmias. Therefore, we compared the results of epicardial and endocardial programmed ventricular stimulation in 58 consecutive patients in whom pairs of steel wires were placed over the right ventricle during surgery. The stimulation protocol consisted of single and/or double premature stimuli during sinus rhythm and paced ventricular drives of 500, 430, 370 and 330 ms. Pre-operatively, all patients had inducible monomorphic ventricular tachycardia by endocardial stimulation. Post-operatively, 36 patients were not inducible by either epicardial or endocardial programmed ventricular stimulation, whereas epicardial and endocardial stimulation induced the clinical ventricular tachycardia in six patients and non-clinical ventricular tachycardia in three patients (45/58 patients, 77% concordant). However, in two patients the clinical ventricular tachycardia was induced only by endocardial programmed ventricular stimulation. Non-clinical ventricular tachycardia was inducible in three patients by epicardial stimulation only, and in eight patients by endocardial stimulation only (13/58 patients, 23% discordant). Thus, in 77% of patients an identical result of programmed ventricular stimulation was obtained using epicardial and endocardial stimulation, whereas the results were discordant in 23%. Therefore, epicardial stimulation alone is not sufficient for the post-operative evaluation after map-guided surgery.

Adult↗
PubMed1987

The Björk-Shiley 70 degree convexo-concave prosthesis strut fracture problem (present state of information).

Between June 1980 and June 1983 4028 Björk-Shiley 70 degree convexo-concave prosthetic heart valves were distributed and implanted in Australia, Canada, Europe and South Africa. As of March 1986, a total of 52 outlet strut fractures (1.29%; 70% CL: 1.1%-1.5%) have been reported from 29 implant institutions in 12 countries. The majority (82.7%) occurred in Europe. Intervals between implantation and fracture were 13 days to 45.3 months (mean: 18.4 months; 70% CL: 16.6 months-20.1 months). The mortality rate after strut fracture was 78.7% (70% CL: 72.5%-84.9%). Upon stratification of the fracture by valve sizes and types it becomes evident that 75% (70% CL: 68.8%-81.2%) of all fractures are related to the sizes 29 mm to 33 mm (which virtually represent the same valve size) and predominantly to mitral valves (p less than 0.01). The large valves again have been stratified into two subsets, namely those fabricated from flanges originally machined as Björk-Shiley 60 degree convexo-concave valves (group I) and later produced valves machined initially to 70 degree specifications (group II). In group I the fracture rate was 5.2% (70% CL: 4.2%-6.2%) versus 1.6% (70% CL: 1.1%-2.1%) in group II (p less than 0.01), which identifies the group I 29 mm-33 mm Björk-Shiley 70 degree convexo-concave valves as the highest risk group for strut fracture. The rates are based upon all available information as of March 16, 1986.(ABSTRACT TRUNCATED AT 250 WORDS)

Heart Valve Prosthesis↗
PubMed1987

[Surgical treatment of patients with Wolff-Parkinson-White syndrome].

Patients with supraventricular reciprocating tachycardias or atrial fibrillation with rapid ventricular response mediated over an accessory pathway may be difficult to treat. In cases of medically refractory arrhythmias, or in patients requiring operations for other cardiac abnormalities, surgical division of an accessory pathway was attempted in 18 consecutive patients. The major indication for operation was drug refractory tachyarrhythmias in 13 patients, whereas 5 patients were operated upon primarily because of either aortic or mitral or tricuspid valve replacement. After careful preoperative and intraoperative electrophysiological evaluation, all patients revealed only one bypass tract. The location of the accessory pathways were as follows: 16 left free-wall and 2 right free-wall. Surgical division was attempted using the "Sealy-Technique". 14 accessory pathways were divided successfully and in 2 patients they were made responsive to previous ineffective medical therapy. In one patient operation was unsuccessful. In 3 patients reoperations were necessary because of the reappearance of accessory pathway conduction. One patient with associated Ebstein's anomaly died intraoperatively. During a follow-up of 26 +/- 21 months, 14 patients were free of tachyarrhythmias without antiarrhythmic medication, whereas 2 patients responded to previously ineffective therapy. Another patient undergoing unsuccessful surgical ablation was treated with amiodarone. These results indicate that by employing the Sealy-Technique accessory pathways could be successfully divided in 14 of 18 patients (78%) and additionally made responsive to previously ineffective antiarrhythmic therapy in 2 patients (11%) (total success = 89%).

Adolescent↗
PubMed1987

Direct operations for the management of life-threatening ischemic ventricular tachycardia.

UNLABELLED: Between June 1978 and 1986, 93 consecutive patients underwent electrophysiologically guided operations for life-threatening recurrent sustained ventricular tachycardia mostly associated with other surgical procedures, such as left ventricular resection (aneurysmectomy) and coronary artery bypass grafting. DATA: Eighty-seven percent of the surviving patients were free of spontaneous ventricular tachycardia return or sudden death 1 year after the operation and 77% at 5 years. The instantaneous risk of ventricular tachycardia return was highest immediately after operation, declined rapidly, and by 2 weeks postoperatively had merged with the constant hazard phase, which persisted as long as the patients were observed. Endocardial resection, rather than encircling endocardial myotomy, increased the risk of spontaneous ventricular tachycardia return/sudden death. Survival rates, including hospital deaths, were 95% at 30 days, 89% at 1 year, and 70% at 5 years after operation. The most prevalent mode of death was heart failure. The absence of anterolateral left ventricular aneurysms and the use of more extended encircling incisional techniques for ventricular tachycardia ablation increased the risk of early and late death. Survival was particularly poor in that subset of patients in whom recurrent sustained ventricular tachycardia returned after operation; the most prevalent mode of death in this group was also progressive left ventricular failure. Inferences: (1) Complete and partial encircling endocardial myotomy incisions are the most effective surgical techniques for malignant ventricular tachycardia ablation. (2) Because of their adverse effects on left ventricular structure and function, the arrhythmogenic tissues have to be localized as precisely as possible, and the encompassing incisions should be kept as limited as possible. (3) The late return of ventricular tachycardia may be more related to a progressive ischemic left ventricular cardiomyopathy than to an inadequate operation.

Cardiac Pacing, Artificial↗
PubMed1985

[Therapy-refractory permanent ventricular tachycardia in the immediate postinfarct period--treatment using endomyocardial ventriculotomy].

Endocardial encircling ventriculotomy was carried out in a 47-year-old male patient because of recurrent drug-resistant permanent ventricular tachycardia complicating acute myocardial infarction. Earliest activation during ventricular tachycardia determined by intraoperative mapping was recorded from the left side of the interventricular septum. At this site, a parital encircling endocardial ventriculotomy was performed. Postoperatively, there was no spontaneous recurrence of ventricular tachycardia. During a postoperative electrophysiologic study, no ventricular tachycardia could be induced. These results indicate that map-guided surgery may be carried out successfully in selected patients with drug-resistant ventricular tachycardia complicating the acute phase of myocardial infarction.

Cardiac Pacing, Artificial↗
PubMed1984

Surgical correction of tetralogy of Fallot (TOF) after palliative operations.

Patients with tetralogy of Fallot and unfavorable anatomy of the right ventricular outflow tract or hypoplastic pulmonary arteries may require primary palliation and subsequent repair (two-stage repair). The concept of palliation includes improvement of the lung perfusion and relief of systemic hypoxia by means of some type of arteriopulmonary arterial shunt or a Brock-type operation. At repair a previously constructed aorto-pulmonary anastomosis has to be closed, which can be done without increased risk for hospital death or postoperative morbidity.

Adolescent↗
PubMed1984

Surgical treatment of ventricular tachycardias. Complete versus partial encircling endocardial ventriculotomy.

Forty consecutive patients underwent electrophysiologically guided encircling endocardial ventriculotomy as treatment for recurrent sustained ventricular tachycardia resulting from coronary artery disease and previous myocardial infarction. Twelve patients (30%, Group I) had a complete encircling endocardial ventriculotomy and 28 (70%, Group II) had a partial encircling endocardial ventriculotomy (54.4% +/- 2.2% of the left ventricular endocardial circumference) at the earliest electrical activation during ventricular tachycardia. There were no significant differences between the two groups in age, sex ratio, New York Heart Association class, coronary disease, aneurysm location, concomitant bypass grafting, and left ventricular function. One patient of Group I and two patients of Group II did not survive the perioperative period (8% versus 7%, not significant). The survivors were restudied electrophysiologically about 3 weeks after the operation. Eight patients of Group I and 19 patients of Group II were free of ventricular tachycardia (no spontaneous or inducible ventricular tachycardia) without antiarrhythmic drugs (73% versus 73%, not significant). The mean follow-up period in Group I is 22.6 months and in Group II, 15.2 months. Five patients of Group I and of Group II developed severe left ventricular dysfunction (46% versus 8%; p = 0.025). Also, congestive heart failure was a significant cause of death in Group I patients (p = 0.036). In conclusion, electrophysiologically guided partial encircling endocardial ventriculotomy is highly efficient as a surgical treatment of recurrent sustained ventricular tachycardia. Complete encircling endocardial ventriculotomy offers no better ablation of arrhythmias and should be avoided because of its apparent hazards to left ventricular performance.

Coronary Disease↗
PubMed1984

[Clinical and electrophysiologic findings following operative therapy of ventricular tachycardias].

40 patients with sustained ventricular tachycardia underwent either complete (n = 12) or partial (n = 28) endomyocardial encircling ventriculotomy ( EEV ). All patients had coronary artery disease, mean age 54 years. Aneurysmectomy was performed in 35 patients. 30 patients also received coronary artery bypass grafts. There were 3 perioperative deaths (7.5%): 1/12 with complete and 2/28 with partial EEV . All survivors underwent programmed right ventricular stimulation postoperatively. Ventricular tachycardia was not inducible in 23 of 36 patients (64%). One patient was not studied postoperatively. In contrast, sustained ventricular tachycardia was still inducible in 13 patients. Ventricular tachycardia was considered as "clinical" tachycardia in 9 patients whereas it was a "non-clinical" form in another 4 patients. Thus the electrophysiological failure rate with regard to "clinical" forms was 25%. In 2 of 4 patients with spontaneous recurrences during the first postoperative week, sustained ventricular tachycardia could not be induced during the postoperative electrophysiological study. During follow-up (mean 18 months), spontaneous recurrence of ventricular tachycardia occurred in 2 patients. Cardiac arrest possibly due to coronary bypass occlusion occurred in 1 patient who could be resuscitated. 6 patients died late postoperatively: 4 of congestive heart failure, 1 of re-infarction and 1 of fulminant pneumonia. 3/11 patients (27.3%) with complete and 1/26 (3.8%) with partial EEV died because of congestive heart failure (p less than .03). Thus abolition of spontaneous sustained ventricular tachycardia was successfully achieved in 94.6% of cases surviving surgery (91.9% if the patient with cardiac arrest is included.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrocardiography↗
PubMed1983

[Diagnosis and therapy of ventricular tachycardias].

For the diagnosis of ventricular tachycardia the surface ECG is a sufficient diagnostic tool in most instances. Therefore, invasive electrophysiological studies are normally not indicated for diagnostic purposes, except if the tachycardia has not been documented up to now. However, invasive testing is necessary in every patient with VT for therapeutic reasons. During the study, the tachycardia is induced and terminated by programmed ventricular stimulation and the effect of different antiarrhythmic drugs tested. If no drug is able to suppress the induction of the tachycardia or to render it more difficult, alternative forms of therapy are to be considered. Implantable defibrillators and antitachycardial pacemakers are still at a developmental stage which does not allow a general application yet. In specialized centers, most of these intractable patients are undergoing electrophysiological operations. During operation the "focus" of the tachycardia is localized by means of epicardial and endocardial mapping and excluded by encircling subendocardial incision. In the last years, experimental and clinical studies are focusing on the so-called late potentials as markers for VT. These potentials can be recorded from the body surface by means of the signal averaging technique. Their clinical significance has not been fully established yet.

Cardiac Pacing, Artificial↗
PubMed1983

Isolated atrioventricular discordance. Report of two surgical cases with isolated ventricular inversion.

Isolated ventricular inversion is a term used for a congenital heart malformation with the segmental arrangement atrioventricular (AV) discordance and ventriculoarterial concordance. It describes a condition which from a physiological point of view resembles complete transposition of the great arteries. We have recently seen two patients with this anomaly. Both underwent intracardiac repair by means of a Mustard operation at 10 years and 10 months of age, respectively. Associated lesions in the first patient were an AV septal defect with two AV orifices (partial AV canal, ostium primum defect), partial anomalous pulmonary venous return, and anomalies in the systemic venous drainage. A perimembranous ventricular septal defect complicated the condition in the second patient.

Aortography↗
PubMed1982

Effects of antiarrhythmic surgery on late ventricular potentials recorded by precordial signal averaging in patients with ventricular tachycardia.

In seven patients with documented ventricular tachycardia (VT) and prior myocardial infarction, late potentials (LP) were recorded at the end of or after the QRS complex from the body surface using high-gain amplification and the signal averaging technique (RC filter settings 100 to 300 Hz). In 6 to 7 patients VT could be initiated by programmed right ventricular stimulation; in one case, VT was inducible only from the left ventricle during surgery. Surgery was guided by epi- and endocardial mapping. In most cases besides resection of scar tissue, a partial or complete subendocardial encircling ventriculotomy was performed. Postoperatively, LPs were abolished in five cases, VT being no longer inducible. In the remaining two patients, LPs were still present. VT was still inducible in one of these two cases whereas in the other case, no programmed testing was done postoperatively. These data suggest that the abolition of LPs by surgery is closely related to the disappearance of the propensity to stimulus-induced VT. Thus, the averaging technique represents a new approach to the noninvasive control of the efficacy of surgery in patients with VT and prior myocardial infarction.

Adult↗