[New methods for the detection of high risk patients in cardiology]. / Neue Methoden für die Erkennung von Hochrisikopatienten in der Kardiologie.

Common non-invasive diagnostic methods like Holter monitoring or the analysis of high-resolution ECG and heart rate variability are unable to accurately assess the individual risk for sudden cardiac death, since they describe only statistical, linear or strictly periodic parameters. Using new methods of non-linear dynamics one can now calculate parameters which much better describe the dynamic behaviour of complex systems. The application of these new methods should therefore lead to an improved identification of high-risk patients. The results of this first pilot investigation show on the one hand that ventricular arrhythmias are quick detectable using phase space plots, and on the other hand that the new methods of non-linear dynamics could lead to a new classification of high-risk patients.

Treatment of tachyarrhythmias in a patient with the long QT syndrome by autotransplantation of the heart and sinus node-triggered atrial pacing.

The case history of a 37-year-old woman with the long QT syndrome and drug-refractory paroxysmal ventricular tachyarrhythmias is reported. She was resuscitated eight times between 1980 and 1987. The duration of these attacks increased from a few minutes to 8 hours and the interval between them decreased from 2 years to 4 weeks. An autotransplantation was performed of the anatomically and hemodynamically normal heart. She has had normal QT intervals and has been free of tachyarrhythmias since the operation in June 1987. Because of a slow escape low atrial rhythm, she was treated with a dual-chamber pacemaker programmed in the VDD mode with a coupling interval of 15 msec. The pacemaker wires were connected to the nontransplanted atrial cuff ("atrial" wire) and the transplanted atrium ("ventricular" wire). The hemodynamic effect of the resultant sinus node-driven low atrial pacing was restoration of normal values. This is the first report of successful autotransplantation of the heart for ventricular tachyarrhythmias caused by the long QT syndrome.

Frequency domain analysis of highly amplified ECG on the basis of maximum entropy spectral estimation.

Recognition of patients with high risk for ventricular tachycardia (VT) or sudden cardiac death is of high clinical importance. We have investigated the efficiency of maximum entropy spectral estimation (MES) to detect such risk patients on the basis of highly amplified surface ECG. In comparison with the traditionally applied periodogram (fast Fourier transform), the MES produces sharper and more pronounced peaks in the power density spectrum (PS). The main problem is the influence of residual noise (after averaging), which often leads to additional components in the PS. To completely avoid this negative noise influence we developed a new algorithm, called the variance subtraction method. In a first clinical investigation 86 per cent of patients with myocardial infarction and ventricular tachycardia have shown frequency components above 80 Hz in the PS compared with healthy persons where no frequency components above this 80 Hz level could be detected.

[Acute and long-term effects of pimobendan (UD-CG 115) in NYHA II and III heart failure. Results of a randomized multicenter double-blind study]. / Akut- und Langzeiteffekte von Pimobendan (UD-CG 115) bei Herzinsuffizienz NYHA II und III. Ergebnisse einer randomisierten multizentrischen Doppelblindstudie.

The effects of pimobendan (UD-CG 115) on hemodynamics and exercise capacity after acute (single dose) and chronic (6 month) oral treatment, as well as acute treatment after 6 months were investigated in 67 patients with chronic heart failure of NYHA classes II or III, which had persisted in spite of treatment with diuretics and digitalis. They were treated with pimobendan (2.5 mg bid or 5 mg) or placebo in a randomized, double-blind multicenter trial. With a single administration before and after 6 months' treatment there was-compared to placebo-a significant fall in pulmonary capillary pressure (PCP) at rest (R) and during exercise (E) of 7% to 24%. Right atrial pressure (R) and pulmonary arterial pressure (PAP) (R, E) decreased after pimobendan on day 1; cardiac index (E) increased significantly. All other parameters were not influenced. After chronic therapy, PCP (E), PAP (E), LV stroke work index (E), and pulmonary resistance (R and E) values were significantly lowered by pimobendan when compared to day 1. Exercise duration was prolonged after 6 months by 83 s and 47 s after 5 and 10 mg/day, resp., compared to the placebo group (group difference not significant). Subjective wellbeing was improved in all three groups (no group difference). Clinical symptoms were not altered; six patients (two in each group) died suddenly. Another nine patients discontinued the trial prematurely because of poor efficacy or adverse events (no group difference). Overall, pimobendan was well-tolerated and had favorable effects on both acute and chronic hemodynamics and on exercise capacity. There was no evidence of any tolerance development.

[Automatic classification of the greatly amplified ECG in relation to time and frequency]. / Die automatische Klassifizierung des hochverstärkten EKG im Zeit- und Frequenzbereich.

The non-invasive recording of cardiac micro-potentials from the surface of the body, in particular of the so-called ventricular late potentials from the highly amplified ECG, makes it possible to identify those patients at high risk from severe arrhythmics or sudden death. By using more extensive automatic parameter extraction methods, we were able to increase the detection rate of pathological ECGs. We were also able to show that the calculation of the power density spectrum, in particular on the basis of maximum entropy spectral estimation, in combination with the variance extraction method of eliminating the influence of residual noise, is capable of providing separate additional valuable information.

[Treatment of tachyarrhythmia in a patient with long QT syndrome by autologous heart transplantation and atrial stimulation controlled by the sinoatrial node]. / Lechenie takhiaritmii u bolnoi s sindromom udlinennogo intervala Q-T s pomoshch'iu autotransplantatsii serdtsa i stimuliatsii predserdii, upravliaemoi sinusovym uzlom.

The authors described an operation performed in a female patient aged 37 years who was first examined in 1980. That year she experienced the first ventricular fibrillation episode. The duration of the Q-T interval was 600 msec. She was examined by a comprehensive protocol which enabled coronary abnormalities to be excluded. The operation was made in July 1987 in the Charite Hospital by Dr. Warnke. The operation involved dissection of the nerve connections nearest the heart by cutting the pulmonary artery, aorta, both atria and subsequently suturing by the scheme used in cardiac grafting. The patient rapidly recovered after the surgery. She had a normal Q-T interval and no recurrences of ventricular tachycardias. Following the surgery she displayed disturbances of intraatrial conduction and pacemaker displacement into the lower segments of the right atrium, so she was implanted a DDD-mode pacemaker.

Long QT syndrome associated with inflammatory degeneration of the stellate ganglia.

A well-studied case of intermittent long QT syndrome in a 21-year-old female is presented. Electrophysiologic investigation repeated three times revealed changing sinoatrial and atrioventricular dysfunction and nonsustained ventricular tachycardia. The patient died 29 months after first hospitalization in a stage of electromechanical dissociation after runs of torsade de pointes although she had been treated with repeated anti-inflammatory therapy as well as high doses of propranolol. Postmortem examination demonstrated active inflammation of stellate ganglia. Myocardium appeared normal.

[Hemodynamic examinations concerning the effects of cardiac glycosides in hypertrophic obstructive cardiomyopathy (HOCM)]. / Hämodynamische Untersuchungen zur Herzglykosidwirkung bei hypertrophischer obstruktiver Kardiomyopathie.

Due to fundamental considerations and especially after Braunwald's et al. (1962 (4)) examinations of 5 patients with severe hypertrophic obstructive cardiomyopathy (HOCM) with 0.5-0.75 mg of Ouabain, cardiac glycosides in cases of this disease are to be regarded as contraindicated. Own examinations (right and left-heart catheterizations, monoplane cineangiography of the left ventricle, determination of the cardiac output, and the ejection fraction (EF) were performed in 10 patients with HOCM of different stages. Applying the usual dosage of 0.25-0.375 mg of strophanthin, different hemodynamic effects were observed in discrete forms. In cases with a higher severity, the observations of Braunwald et al. could actually be confirmed. The left ventricular systolic pressure gradients were increased, but cardiac output, left ventricular enddiastolic pressure, pulmonary pressure and resistance, and also arterial pressure and peripheral resistance behaved differently. EF increased slightly. The right infundibular gradients were decreased with one exception, or resp., they were unchanged. Obviously, HOCM reacts especially unfavourably with so-called left-ventricular cavity obliteration. The main importance might belong to the behaviour of the free lumen of the left ventricle. In regard of the principally reserved attitude towards the cardiac glycoside therapy in HOCM, no change has occurred. Only in patients with atrial fibrillation and a rapid heart rate, a therapy trial could be considered, if necessary in combination with beta-blocking agents or calcium antagonists under hemodynamic control. In cases of HOCM with serious obstruction and signs of cardiac failure and inadequate affecting by calcium antagonists, an early surgical intervention should be executed.