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Biomedical subjects

O Pahlm

Publications and source records attributed to O Pahlm.

At least 73 records · Page 4Linked to original sources
PubMed1988

Vectorcardiogram synthesized from a 12-lead ECG: superiority of the inverse Dower matrix.

Vectorcardiographic (VCG) criteria for the diagnosis of, for example, myocardial infarction and right ventricular hypertrophy, are superior to the corresponding 12-lead ECG criteria. Contour and rotation of the QRS loops are important parts of these VCG criteria that have no direct counterpart in the 12-lead ECG. Therefore, attempts have been made to synthesize VCGs from 12-lead ECGs for diagnostic purposes. Visual comparison of QRS loops from the Frank VCG and three different synthesized VCGs was made by three independent observers to determine which method produces the most Frank-like QRS loops. The inverse transformation matrix of Dower proved to be the best method of synthesis. Normal limits for some clinically important measurements in VCG interpretation were calculated for this synthesis method and the Frank VCG.

Adult↗
PubMed1988

Visceral improvement following combined plasmapheresis and immunosuppressive drug therapy in progressive systemic sclerosis.

In a two-year prospective therapeutic trial, 15 patients with progressive systemic sclerosis (PSS) were treated with immunosuppressive drug therapy with or without long-term plasmapheresis. Before the trial all patients had severe involvement of either the esophagus, lungs or kidneys. One patient died of renal failure and another 2 patients withdrew unimproved. In the remaining 12 patients, objective improvement occurred in all but one. The degree and extent of skin involvement decreased significantly (p less than 0.01). Cineradiography revealed increased esophageal motility in 4 patients. Pulmonary function measured as total lung capacity and static lung compliance improved (p less than 0.01). In 4 patients the number of premature atrial or ventricular contractions at 24 h ECG monitoring decreased, as did the concentrations of immunoglobulins and ANA titres in serum. Although it could not be ascertained whether the clinical improvement was associated with combined therapy or immunosuppressive drug treatment alone, our results suggest that immunosuppressive therapy is beneficial in advanced PSS.

Adult↗
PubMed1987

Sex- and age-related normal limits for the QRS complex in vectorcardiography.

In order to provide reference values for vectorcardiography (VCG), which are relevant with regard to sex, age and available computer technology. VCG from a normal material were studied. VCG according to Frank were recorded in 159 men and 193 women, healthy and randomly selected from a defined caucasian urban population. The technique used includes noise reduction by averaging and a spatial algorithm for QRS delineation. The results are given separately for men and women and for young and old subjects. Significant differences between these groups were found to be common and of potential importance for interpretation of VCG. Discrepancies between our results and other reports on normal ranges can be explained by both different techniques used and different composition of the material studied. On the basis of our data normal limits for a number of measurements, commonly used in diagnostic criteria for myocardial infarction and ventricular hypertrophy are reported.

Adult↗
PubMed1987

Arrhythmogenicity from combined bronchodilator therapy in patients with obstructive lung disease and concomitant ischemic heart disease.

Twenty-four patients (five women) aged 53-72 yr with both ischemic heart disease and asthma or chronic bronchitis receiving oral beta 2-agonists also received additional bronchodilating therapy with theophylline (600 mg daily), enprofylline (600 mg daily) or placebo. The study was double-blind, randomized, triple-crossover with each regimen given for two weeks. Holter monitoring was used during 48 consecutive hours in each period. Compared with placebo, addition of theophylline and enprofylline were associated with an increased mean hourly heart rate of 6 bpm (p less than 0.001). A small, but statistically significant (p less than 0.05) increase in mean hourly frequency of premature ventricular beats (PVBs) occurred with enprofylline as compared with placebo. However, in only two patients with enprofylline (and one patient with theophylline) the increase in PVBs was such that a clinically relevant proarrhythmic effect seems possible. Furthermore, ventricular tachycardia was not more frequently observed with any xanthine than with placebo. Thus, combined oral bronchodilator therapy is not contraindicated in patients with obstructive lung disease and concomitant ischemic heart disease. Holter monitoring is recommended to assess the individual patient's response to such therapy.

Aged↗
PubMed1985

Esophageal ECG recording--a valuable diagnostic tool in dual chamber pacing.

The interpretation of the ECG of a dual chamber pacemaker necessitates the identification of atrial activity. This is a prerequisite for the evaluation of pacemaker function and for the correct adjustment of programmable pulse generators. The assessment of atrial capture in standard 12-lead ECGs is, however, sometimes rather difficult. Esophageal ECG recording by means of a reusable unipolar electrode, inserted transnasally, and connected to a standard ECG recorder, is a simple, rapid and inexpensive method for the reliable identification of P-waves. Clinical examples are presented to illustrate the value of this technique in determining atrial capture and as a tool for the differential diagnosis of pacemaker-involved tachycardias. The use of esophageal ECG recording in the clinical follow-up of patients with dual chamber pacemakers is recommended.

Arrhythmias, Cardiac↗
PubMed1985

Does a computer-based ECG-recorder interpret electrocardiograms more efficiently than physicians?

The quality of ECG-interpretations by a computer-based ECG-recorder has been compared with those carried out visually by physicians in routine clinical practice. Independent reports have been analysed on 474 routine ECGs taken in the medical emergency and out-patient departments, as well as in general practice. Computer reports were available for all of the ECGs, but the physicians had not annotated their interpretations in 11% of them. Eighty-two per cent of the computer-interpretations were adjudged as being satisfactory. The corresponding figure for the physicians' interpretations was 64%. The computer-based ECG-recorder was found to be better than the physician at interpreting ECGs.

Diagnosis, Computer-Assisted↗
PubMed1985

Cardiac arrhythmias in patients with mild-to-moderate obstructive lung disease. Comparison of beta-agonist therapy alone and in combination with a xanthine derivative, enprofylline or theophylline.

Long-term ambulatory Holter-monitoring was used to evaluate the arrhythmogenic effects of beta 2-agonist therapy, alone and in combination with a xanthine derivative, theophylline or enprofylline. Twenty patients (mean age 51 years) with mild-to-moderate obstructive lung disease (bronchial asthma or chronic bronchitis), but without concomitant ischemic heart disease were studied. Compared with beta 2-agonist therapy alone, both combined regimens were associated with a small but significant increase in the frequency of ventricular arrhythmias. Few serious arrhythmias were observed, however, and the clinical significance of these findings is thought to be minor. Although adenosine has been suggested to have an antiarrhythmic effect, a difference between theophylline and enprofylline in the effect on adenosine (theophylline but not enprofylline being an adenosine antagonist) would appear to be of less cardiac relevance in patients without ischemic heart disease.

Adrenergic beta-Agonists↗
PubMed1981

Conventional versus computer-aided interpretation of long-term ECG recordings--aspects of precision and economy.

In a sample of 60 12-h long-term ECG recordings we compared a computer-aided analysis method to a conventional scanning technique for diagnostic precision and time consumption. As regards diagnostic precision no significant difference between the methods could be found. Both were considered efficient in detecting episodes of arrhythmia. Using the computer-aided method a physician spent an average of 16 min on analyzing a recording and writing the diagnostic report. The conventional method required 69 min from an ECG technician and 9 min from a physician for each recording. From these figures we conclude that about 750 12-h recordings/year are required to outweigh the extra annual cost for the computer, if it is used only for long-term ECG analysis. If the computer can also be used for other purposes the system for long-term ECG analysis is profitable with a smaller annual number of recordings.

Adult↗
PubMed1980

I.V. practolol during microlaryngoscopy. Effect on arterial pressure, heart rate, blood glucose and lipolysis.

Twenty-five patients undergoing microlaryngoscopy were anaesthetized with thiopentone and nitrous oxide with suxamethonium as a muscle relaxant. Thirteen received practolol 0.4 mg kg-1 and atropine 1.5 mg i.v. shortly before anaesthesia. During anaesthesia practolol 0.2 mg kg-1 was given. Twelve (control) received atropine 0.5 mg before anaesthesia. Practolol reduced the frequency of tachycardia and arrhythmia. The treatment group had a greater reduction in systolic arterial pressure during induction. The hypertensive response to laryngoscopy was not significantly attenuated by practolol. A weak hyperglycaemic response to microlaryngoscopy was not affected, nor was the plasma concentration of glycerol.

Aged↗
PubMed1980

The clinical impact of long-term ECG recording. A retrospective study of 150 patients.

One-hundred and fifty patients referred for long-term ECG (LECG) recording at a university hospital were monitored for 12 hours or more. The referring physicians' patient records were studied 12 months or more after monitoring in an attempt to establish if and how LECG had affected patient management. Seventeen patients were treated with permanent pacemakers and 13 with antiarrhythmic drugs as a direct result of LECG. Thirteen patients who experienced symptoms with concomitant cardiac arrhythmia at the time of recording were considered not to require treatment. In 17 patients who experienced symptoms without concomitant arrhythmia during monitoring, cardiac arrhythmia could be ruled out as the cause of the symptoms. In 9 more patients, LECG was considered to have contributed "valuable clinical information" (which could not be obtained by other diagnostic methods) to the referring physician. Thus, LECG was considered to have affected the referring physician's management of the patients in 69 cases (46%).

Arrhythmias, Cardiac↗
PubMed1979

Compact digital storage of ECG's.

The technique of predictive coding is applied to the problem of reversible compression of digitized electrocardiograms. Integer-based predictors and MMSE predictors are studied as regards performance at varying sampling rates and digital resolutions for both long-term ECGs and ECGs recorded at rest. It is concluded that MMSE predictors are to be preferred only in the case when the ECG is oversampled (i.e., the sampling rate is much higher than twice the cut-off frequency of the presampling filter). In other cases the integer predictor which yields the so-called 2nd differences is superior. The problem of encoding the resulting residuals with a variable-length code is studied for long-term ECGs digitized at 100 Hz and using 8 bits digital resolution. The code has a simple struture leading to speed of execution while the efficiency loss is small.

Computers↗