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Biomedical subjects

K Hellberg

Publications and source records attributed to K Hellberg.

At least 19 recordsLinked to original sources
PubMed1999

[Spontaneous dissection of the coronary arteries: a rare cardiologic diagnosis].

A 55-year-old woman who was admitted to hospital with acute chest pain as a case of emergency suffered from an acute anteroseptal myocardial infarction. Four weeks later coronary angiography revealed a long dissection of the left anterior descending artery (LAD) as well as a significant stenosis of the left main and the proximal circumflex. Cardiovascular surgery was done subsequently. In addition to myocardial revascularization using coronary artery bypass grafts a readaptation of the dissecting artery walls and a proximal ligation of the LAD before anastomosis were performed. Clinical data, pathogenesis, and indications for medical and surgical treatment of spontaneous artery dissection are presented.

Aortic Dissection↗
PubMed1999

Atrial fibrillation after coronary artery bypass surgery: association with changes in G protein levels in mononuclear leukocytes.

Atrial fibrillation (AFib) is a frequent complication of coronary artery bypass grafting (CABG). Its cause, however, is unknown. As the adrenergic system is involved in some types of AFib, we hypothesized that a change in guanine nucleotide-binding protein (G protein) expression plays a role in the development of post-CABG AFib. In 28 patients undergoing CABG surgery, the G(s alpha)/G(i alpha) ratio (stimulatory/inhibitory G protein alpha) at the protein (Western blotting) and mRNA (reverse transcription polymerase chain reaction) levels was measured before and after surgery. As a suitable test system allowing multiple analysis mononuclear leukocytes (MNL) were chosen. The perioperative change of the G(s alpha)/G(i alpha) ratio of protein and mRNA was significantly different in patients who subsequently developed AFib (eight patients) and in patients who did not (20 patients; P<0.01 and <0.001, respectively). On average, the protein G(s alpha)/G(i alpha) ratio decreased from 1.79+/-1.13 (mean+/-SD) to 1.32+/-0.69 in patients without AFib (P=0.1, n.s.) whereas a significant increase from 0.86+/-0.44 to 1.62+/-0.65 (P<0.01) was observed in patients subsequently developing AFib. The mRNA G(s alpha)/G(i alpha) ratio decreased significantly from 0.53+/-0.24 to 0.36+/-0.11 in patients without AFib (P<0.01) whereas a significant increase from 0.31+/-0.14 to 0.47+/-0.13 was observed in those who subsequently developed AFib (P<0.05). These results indicate that an increase of the G(s alpha)/G(i alpha) ratio in MNL is associated with AFib after CABG surgery and possibly may be used as a prognostic indicator of this complication.

Adult↗
PubMed1998

[The abdominal emergency after heart surgery interventions].

In 4726 patients undergoing cardiopulmonary bypass surgery in a 5-year period 15 major acute abdominal complications (0.3%) occurred, with an overall mortality rate of 47%--compared with a mortality rate of 3.2% for all patients undergoing heart surgery (p < 0.0001). Patients with combined cardiac operation (ACB and valve replacement) or those requiring an intraaortic balloon pump were more likely to develop abdominal complications; however, complications can not be predicted. The focus should be on early diagnosis and therapy, especially in acute mesenteric ischemia, in close cooperation between heart and general surgeons to improve prognosis.

Abdomen, Acute↗
PubMed1996

Non-isotopic competitive reverse transcription polymerase chain reaction coupled with high performance liquid chromatography to measure beta 2-receptor messenger RNA in the human heart.

We describe an application of competitive reverse transcription-polymerase chain reaction (PCR) coupled with HPLC for quantification of beta 2-adrenergic receptor messenger RNA (mRNA) in human atrial tissues removed during cannulation for cardiopulmonary bypass operations. We constructed an internal standard which was reverse transcribed in different concentrations together with constant levels of cellular RNA and subsequently PCR amplified. The competitor RNA shows the same beta 2-adrenergic receptor primer sequences as the cellular mRNA but yields a different-sized product. This allows resolution of the amplified copy DNA (complementary DNA, cDNA) fragments with a specific HPLC column. The concentration of beta 2-adrenergic receptor mRNA is derived from the ratio between the peak intensities corresponding to the amplified competitor and target products. We assessed the imprecision, accuracy and sensitivity of the method. Concentrations of beta 2-adrenergic receptor mRNA of 22.7 +/- 15.2 x 10(6) molecules per micrograms total RNA in patients treated with beta 2-antagonists were not significantly different from control patients showing 16.8 +/- 9.9 x 10(6) beta 2-adrenergic receptor mRNA molecules per microgram total RNA (Mean +/- SD). Competitive reverse transcription PCR is a highly specific, non-radioactive procedure for quantification of beta 2-adrenergic receptor mRNA and simultaneously other gene expression levels of interest in atrial tissue specimens and may therefore be used to advance our understanding of heart muscle disease.

Adrenergic beta-Antagonists↗
PubMed1995

Percutaneously adjustable pulmonary artery band.

BACKGROUND: Pulmonary artery banding, originally introduced to palliate increased pulmonary blood flow, is now primarily used for complex congenital cardiac defects with a prohibitive risk in the early repair, such as tricuspid atresia, or occasionally to prepare the left ventricle for eventual arterial switch. Conventional banding is, however, often poorly tolerated, and the precise adjustment required to reduced pulmonary blood flow or sufficiently challenge the left ventricle is difficult and can cause life-threatening hemodynamic changes. METHODS: We designed a band that allows accurate tightening and is reversible during the operation and at the bedside with the chest closed, allowing precise gradual adjustment over days, thereby minimizing cardiovascular instability. This design is the extension of previous work done by one of us on an adjustable annuloplasty ring. RESULTS: The band has been used for a 16-month-old child with tricuspid atresia type 1C who had undergone two failed attempts at banding. Hemodynamic measurements after 3 months confirmed achievement of the desired pulmonary pressure. CONCLUSIONS: This design, the simple insertion, and the ability to finely readjust the banding over days, combined with excellent patient tolerance, encourage further use of our adjustable band.

Constriction↗
PubMed1993

[Left cerebral ischemia in mitral valve aneurysm].

An anterior mitral leaflet aneurysm was detected by two-dimensional echocardiography using the transesophageal approach in a 53-year-old patient with cerebral ischemic event. The transesophageal examination allowed a clear description of the aneurysm which was confirmed during surgery. This case demonstrates that transesophageal echocardiography is the method of choice in evaluation of distinct valvular lesions. The importance of TEE examination in patients with a neurological history is evident.

Aneurysm↗
PubMed1990

Magnitude and kinetics of alterations in plasma catecholamines and leukocyte beta-adrenergic receptors in response to anaesthesia and surgery.

We studied the response of the sympatho-adrenal system to varying intensities of different stimuli. Concentrations of norepinephrine and epinephrine in plasma as well as densities of beta 2-adrenergic receptors on mononuclear leukocytes were determined in patients subjected to operations of varying complexity and different types of anaesthesia. In patients undergoing hysterectomy (n = 9), the maximal increases in plasma norepinephrine and epinephrine were 2.7- and 2.8-fold, respectively, corresponding to a post-operative decrease of the mononuclear leukocyte beta 2-adrenergic receptors of 27% after 4 hours. Patients with coronary revascularization (n = 17) were randomly selected to receive either enflurane/N2O or neurolept anaesthesia. During intraoperative periods of stress, such as cardiopulmonary bypass and hypothermia, norepinephrine and epinephrine levels were 2-3 times higher in the neurolept patients, compared with the enflurane patients. In the former group, the respective maximal norepinephrine and epinephrine concentrations were 9.7 and 28 times the vasal values of the non-anaesthetized patients. One day postoperatively, the mononuclear leukocyte beta 2-receptor density decreased maximally by 45 +/- 11% in the enflurane patients, and by 53 +/- 6% in the neurolept patients. As early as two to five days after cardiac surgery, beta 2-receptor densities were no longer distinguishable from the preoperative values. Significant correlations between the increases in catecholamine concentrations and the decreases in beta 2-receptor densities did not exist. It is concluded that enflurane blocks the sympatho-adrenal response to surgical stress more effectively than neurolept anaesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Antipsychotic Agents↗
PubMed1987

[Clinical aspects of global ischemia of the heart].

The vast majority of modern surgical open-heart procedures require a period of global myocardial ischaemia due to the interruption of the coronary circulation, since a bloodless operative field is of great importance for delicate surgical techniques. Several cardiac protective measures have been applied in order to minimize ischaemic damage to the heart muscle: 1. Intermittent myocardial ischaemia, combined with mild to moderate hypothermia: ischaemic periods of 15-30 min at 28-32 degrees C are tolerated. Multiple ischaemic periods are possible after intermittent (3-5 min) reperfusion. 2. Deep hypothermia, combined with ischaemia: myocardial cooling to 18-23 degrees C protects the heart for ischaemic periods of up to 45-60 min. 3. Cardioplegic arrest, combined with hypothermia: a great variety of cardioplegic solutions are still used today in clinical practice. a. Interruption of electrical activity: most cardioplegic solutions use K+ (15-35 mmol/l); complete suppression of electrical processes is not always achieved. b. Interruption of electrical activity and buffering of glycolytic end products. St. Thomas-, Kirklin-Solution, blood cardioplegia and their multiple variations can result in an 3-5 fold tolerance to myocardial ischaemia. c. Interruption and blockade of electro-mechanical activity, combined with an effective buffering. Bretschneider-HTK cardioplegia equilibrates the extracellular space due to a 6-10 min infusion of the cold, crystalloid solution and allows uninterrupted ischaemic periods of more than 2 h under clinical conditions. In order to achieve optimal cardiac tolerance to global ischaemia a careful protocol of perioperative myocardial proection has to be followed. Most heart centers use a combination of hypothermia and effective cardioplegia.

Cardioplegic Solutions↗
PubMed1985

[Experiences with telemetry-supported pacemaker controls in patients with VVI pacemakers].

Investigations on telemetry-supported pacemaker control were carried out in 55 patients with the VVI-pacemaker Quantum (Intermedics). The investigations were done at least once during the 6-24 month period after implantation. The telemetry function was utilised for pacemaker programming, for clarifying pacemaker defects and for characterising the type of pacemaker electrode used. It could be shown that the Osypka spiral electrode VY (Dr. Osypka) had a lower impedance, and greater pulse width and charge threshold in comparison with the two other electrodes used (Encor, Cordis; Polyflex, Intermedics). In 38 of the 55 patients (69%) a pulse amplitude of 2.7 V could be chosen, whereas an amplitude of 5.4 V was programmed in the rest. Pacemaker sensing threshold was set to values between 2.4 and 3.0 mV. Pacemaker problems appeared in three patients; in one patient due to programming too economically and in the other two due to pacemaker defects.

Adult↗
PubMed1985

[Valvuloplasty and peripheral angioplasty with coronary dilatation catheters].

The further development of coronary balloon catheters has encouraged their use for dilating small vessels of other organs and stenoses in larger vessels not passable by conventional catheters. The technique was used successfully as a primary intervention in two stenoses of the external carotid artery preparatory to extra-intracranial anastomosis, in four anastomotic stenoses in three patients with Blalock-Taussig anastomosis, and in a subtotal anastomosis of a Cimino shunt. After failed dilatation attempts with a standard dilatation catheter in three patients with four renal artery stenoses and two with subclavian artery stenosis, coronary angioplasty catheters successfully dilated the stenoses. In two infants with severe valval aortic stenosis and left-heart failure, retrograde transluminal balloon dilatation reduced the transvalval gradient from 70 to 30-40 mm Hg.

Adolescent↗
PubMed1984

Pacemaker-mediated tachycardias: a new modality of treatment.

Three patients with pacemaker interactive drug resistant tachycardia underwent invasive electrophysiological studies. In the first patient, the retrograde conduction of the artificial reciprocating tachycardia was provided by two right-sided accessory pathways and the antegrade conduction by an atrial synchronous pulse generator. In addition, AV-nodal tachycardia occurred alternately. In the second patient with intermittent atrial flutter, the AV node and, coincidentally, an AV sequential pulse generator provided high-rate antegrade conduction to the ventricles. In the third patient with surgical complete heart block, intermittent AV-nodal tachycardia induced retrograde atrial activation while an atrial synchronous pacemaker provided the antegrade conduction. Electrode catheter exploration of the heart allowed localization and closed-chest ablation of the accessory pathways or AV node by delivering two to seven 200-joule direct-current shocks through the appropriate electrode of the exploring catheter. Thereby, pacemaker-mediated arrhythmias could be controlled in these patients in the follow-up of 6 to 8 months.

Adult↗
PubMed1981

Surgical treatment of various types of left ventricular outflow tract stenosis by aortoventriculoplasty--clinical results.

Since 1974 the new concept of aortoventriculoplasty (AVP) has been applied clinically in Göttingen. Out of 1,112 patients with various types of congenital aortic stenosis 502 patients have undergone commissurotomy, resection of a subvalvular ring, myotomy and supravalvular patch plasty. Fifty-seven patients were treated by AVP, in only 11 patients was AVP the first procedure, 46 had had one or more previous operations. Total hospital mortality was 12.2%; in the last 37 cases there was only one death. Two patients suffered permanent AV block. The mean left ventricular-aorta gradient was reduced from 94 +/- 24 mmHg to 14 +/- 15 mmHg after AVP. In our clinical material the indications for AVP (n = 57) have been the following: valvular aortic stenosis with narrow annulus (8 patients), diffuse subaortic stenosis (20) (from collar-like to tunnel-like, out of these patients 6 with Shone-complex), multi-level stenosis (20), outgrown prosthesis (4), hypertrophic obstructive cardiomyopathy (5). In comparison to the apico-aortic conduit procedure and total replacement of the aortic root by homograft, the clinical results indicate AVP to be a simple and easy-to-apply operative technique.

Adolescent↗