Konrad Brockmeier

Magnetocardiography and exercise testing

Twenty healthy male subjects (age range, 15-25 years; median, 21 years) underwent magnetocardiography during physical exercise. Significant ST-segment displacements of the magnetic signal were found during exercise at a heart rate of 120 beats/min compared to the magnetic signal at rest (P < .001). Since no significant ST-segment changes were found in the electrocardiogram recorded simultaneously with the magnetocardiogram, it is concluded that the magnetocardiogram shows junctional ST-T segment changes earlier than the electrocardiogram.

Fragmented ventricular depolarization detectable in the QRS complex of the magnetocardiogram after filtering with binomial non-recursive filters

High frequency components of the cardiac depolarization are considered important indicators of risk for sudden death due to VT/VF applied a non-recursive binomial high pass filter of the 90th order with a cutoff frequency at 37 Hz in order to search for high frequency components throughout the myocardial depolarization of signal averaged high resolution magnetocardiograms. Numerical quantification of the fragmentation resulted in a score with score values in a control group at (means SDD) 19/spl plusmn/5, in a post MI group at 27/spl plusmn/12 and in MI patients with VT at 42/spl plusmn/15. Sensitivity for VT was 0.91 and specificity 0.86. Thus fragmented activity could be detected not only in the terminal part of the depolarization.<<ETX>>

Magnetocardiography in Patients with Cardiomyopathy and Operated Congenital Heart Disease

Patients with dilated and hypertrophic cardiomyopathies represent a high risk group for sudden cardiac death (Griffin et al.,1988 and McKenna et al.,1988). Usually they die from ventricular fibrillation as a result of micro-reentry mechanisms in the severely compromised myocardium (Swerdlow et al.,1983). Most often the left ventricular myocardium is involved. These cardiomyopathies are either acquired as the result of viral infections or they are the result of an inborn error of metabolism. A comparable anatomical and functional state of the heart can be seen after surgical correction of Tetrade of Fallot (TOF). These hearts offer a suitable model of abnormal pressure and/or volume load of the right ventricular myocardium. The significant mortality and morbidity in this patient group is also related to severe ventricular arrhythmias. Because mortality in both groups of patients depends on pathological electrophysiological phenomena, which usually can only be studied by invasive catheter procedures, the possibility of a non-invasive assessment of these changes by magnetocardiography is an intriguing idea.

Magnetocardiography in Patients with the Long QT-Syndrome

Patients with Romano-Ward Syndrome show abnormal long QT-intervals in ECG and have a high risk of sudden cardiac death. The QT-syndrome is a pure electrophysiological disease in otherwise normal hearts. The underlying electrophysiological mechanism triggering ventricular flutter/fibrillation in these patients is an uneven depolarization and repolarization of the myocardium and the specialized conducting tissue (Schwartz et al., 1975). Like in other autosomal dominant inherited diseases expression of symptoms is variable among family members. Up to now a specific method for the discrimination of these high-risk patients does not exist.

Syndrome of the posterior and anterior root in a late isolated CNS relapse of c-ALL. Case report.

A 15 year-old girl who had c-ALL diagnosed in 1982 was presented in our clinic suffering from an ascendend flaccid paresis and dysaesthesia of both legs. These are typical symptoms of polyradiculitis of the nerve roots L2-S2. A lumbal puncture revealed a pleocytosis with lymphoblasts which were up to 40% CD10 (cluster of differentiation) up to 70% CD19 and TdT (terminal transferase) positive. The diagnosis of late isolated CNS relapse was made. It is assumed that local residual infiltrations of leukemic cells into the nerve roots L2-S2 got into cell cycle and caused these rare CNS leukemia symptoms. Therefore the value of a craniospinal irradiation to prevent a CNS and systemic relapse is discussed.

Intra-QRS analysis of high frequency signal components in patients with congenital heart disease

Patients with congenital heart disease were investigated after operation using the echocardiogram, signal-averaged ECG (SAECG) and Holter ECG. 32 patients, age 13.1 y (5-31 y) and 13 controls, 14.0 y (8-21 y), were compared. Together with Butterworth filtering a second high pass filter (FIR digital filter) was introduced to analyse high frequency components not only at the end of the QRS complex. FIR high pass filtering of the whole QRS showed a significant correlation between impaired left ventricular ejection fraction and more fractionated QRS in the SAECG (p<0.003). No correlation was found between dysrhythmias in the 24-hour Holter ECG and SAECG findings. High frequency intra-QRS signal components seem to be related to functional impairment in patients with congenital heart disease after operation.