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Biomedical subjects

M Hellerstedt

Publications and source records attributed to M Hellerstedt.

3 recordsLinked to original sources
PubMed1982

Pacing threshold interval with decreasing and increasing output.

The study was made in 44 patients, of which 23 received a new endocardial electrode and 21 were investigated during pulse-generator replacement. Indication for pacemaker therapy was sino-atrial bradycardia in 12 patients and atrio-ventricular block in 32 patients. When the pacing threshold was determined with decreasing output it was found to be 0.6V/0.7 mA for new implantations and 2.0 V/2.0 mA with pulse generator replacement. When determined with increasing output the threshold was found to be an average 0.20 V/0.20 mA higher than when determined with decreasing output (threshold interval). The maximal difference observed was 0.70 V/0.55 mA. This threshold interval was of the same size irrespective of pacemaker indication and spontaneous activity and whether the electrode was newly implanted or not. Pacemaker ventricular block of Mobitz type I with Wenckebach periodicity was never observed.

Bradycardia↗
PubMed1980

Electrocardiographic diagnosis of ventricular septal infarction.

To find electrocardiographic criteria for ventricular septal infarction, two series of ECGs were studied, all without fascicular/bundle branch block and complete heart block. One series consisted of the ECGs recorded at thallium-201 scintigraphy in 49 patients 2-3 weeks after an acute myocardial infarction (AMI): in this series the 14 patients with a defect in the septal wall of the left anterior oblique view were compared with the 35 without. The other series consisted of the last premortal ECGs in 20 AMI patients with and in seven without a septal involvement of the infarct at autopsy. The best criterion from earlier literature ws absence of a q wave in lead V6, showing a sensitivity of 53% in the combined scintigraphy and autopsy series. The predictive value of a positive test was 75%. The very first QRS vector in the frontal plane tended to discriminate better than absence of a q in lead V6. With a similar predictive value, 71%, the sensitivity of a deviating vector (+ 120 degrees to -60 degrees and -120 degrees to -180 degrees) was 65% in the combined scintigraphy and autopsy groups. Most of the patients with a deviating vector showed this on admission. The clinical importance of an early diagnosis of septal involvement in AMI remains to be settled.

Adult↗