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Telemonitoringsysteme stehen heute zur Uberwachung von Patienten mit implantierten Herzschrittmachern, Defibrillatoren (ICD) und kardialen Resynchronisationssystemen (CRT) in der klinischen Praxis zur Verfugung. Trotz unterschiedlicher technischer Umsetzungen der Hersteller haben diese Systeme einen einheitlichen Aufbau. Mit Telemonitoring konnen Daten zum Aggregat-, Arrhythmie- und Herzinsuffizienzmanagement zeitnah ubertragen werden. Die Arzte konnen uber passwortgeschutzte Internetplattformen jederzeit sicher auf diese Daten zugreifen.

The variability of electric and magnetic signals from the heart during the depolarization phase is investigated. A signal processing method is developed which provides estimates for the beat-to-beat variability of the QRS-complex. The method is based on the decomposition of the depolarization signal into bandpass signals by means of the Morlet wavelet transform. The beat variability of the depolarization signal is estimated by normalized variances of the envelope and instantaneous frequency of bandpass signals. Time intervals of the bandpass filtered depolarization signals having a high signal-to-noise ratio are selected by applying an analysis based on phase statistics. The method was tested by experimental data taken from ECG and MCG measurements of healthy persons and patients prone to malignant ventricular tachycardia (VT) or ventricular fibrillation (VF). Results suggest that the calculated variance parameters permit the characterization of beat variable depolarization signals and distinguish VT/VF patients from healthy persons. The method developed can be used to obtain additional information concerning abnormal heart signals which is attenuated when applying signal averaging.

ZusammenfassungDie linksatriale Katheterablation hat sich als therapeutische Option bei symptomatischem paroxysmalem oder persistierendem Vorhofflimmern (VHF) etabliert. Bei der Mehrheit der Patienten kann nach teils mehrfachen Ablationen eine suffiziente Symptomkontrolle erreicht werden. In vielen Fällen kann ein langfristiger Erhalt des Sinusrhythmus erzielt werden, was für die Vermeidung von VHF-assoziierten Komplikationen von Bedeutung sein könnte. Diese Arbeit gibt einen Überblick über mögliche neurologische Komplikationen der linksatrialen Katheterablation. Neurologische Komplikation treten nach linksatrialer Katheterablation bei 0,4 bis 1,2% der Patienten auf und werden vorwiegend durch akute zerebrale Ischämien bedingt. Nicht ischämisch bedingte neurologische Komplikationen sind sehr selten und werden hauptsächlich durch Phrenikusläsionen hervorgerufen. Zudem geht die sporadisch periinterventionell induzierte atrio-ösophageale Fistel in der Mehrzahl der beschriebenen Fälle mit neurologischen Komplikationen einher. In Abhängigkeit vom eingesetzten Ablationssystem können bei Patienten ohne fokal neurologisches Defizit postinterventionell in variierender Häufigkeit akute zerebrale Läsionen nachgewiesen werden. Die klinische Bedeutung dieser mittels MRT detektierten zerebralen Ischämien kann noch nicht beurteilt werden.

ZusammenfassungVorhofflimmern (VHF) ist die häufigste anhaltende Rhythmusstörung in der täglichen Praxis und trägt ein ca. fünffach erhöhtes Risiko für einen ischämischen Schlaganfall. Um ein aktuelles Abbild von Diagnostik und Behand-lung sowie von langfristigen Komplikationen und Prognose von Patienten mit VHF in Deutschland zu erhalten, wurde 2003 im Kompetenznetz Vorhofflimmern ein Patientenregister etabliert. Erste Ergebnisse weisen daraufhin, dass die Rate der oralen Anti-koagulation mit 67% mit den Ergebnissen anderer europäischer Register vergleichbar ist. Insbesondere ältere Patienten (ab dem 70. Lebensjahr) werden nicht ausreichend mit einer erforderlichen oralen Antikoagulation behandelt. Die klinisch übliche Risikostratifizierung nach dem CHADS2-Score hat in der klinischen Praxis nur einen limitierten Einfluss auf die Entscheidung zur Antikoagulation. Unterschiedliche Antikoagulationsraten in spezialisierten Zentren gegenüber nicht kardiologischen Einrichtungen sind nur zum Teil durch Unterschiede in Altersstruktur und Begleiterkrankungen zu erklären. Entsprechend wird die Antikoagulation bei VHF zur Prävention ischämischer Schlaganfälle weiter unzureichend genutzt.

Die isolierte linksventrikulare Noncompaction-Kardiomyopathie (LVNC) gehort zu den seltenen Kardiomyopathien. Bei der LVNC bestehen typischerweise prominente Trabekel und tiefe Rezessus, die insgesamt als ein 2-schichtig verdicktes Myokard erscheinen. Dabei dominiert eine Schicht als nicht kompaktiertes und eine als kompaktiertes Myokard. Klinischer Standard zur Diagnostik der LVNC ist die Echokardiographie, wobei es verschiedene diagnostische Kriterien gibt. In schwierigen Fallen ist die kardiale Magnetresonanztomographie wegen ihres ausgezeichneten nativen Kontrastes zwischen Blut und Myokard hilfreich. Die meisten Patienten weisen Symptome einer chronischer Herzinsuffizienz auf. Haufig werden im Verlauf Thrombembolien und Arrhythmien beobachtet. Eine kausale Therapie gibt es nicht, daher sind Therapieansatze auf die Behandlung der Herzinsuffizienz und die Pravention von Thrombembolien begrenzt.

The changes in the demographic structure, the increasing multi-morbidity in connection with a rise in the number of chronic illnesses and the absence of an effective coordination of the different levels of health care services with its discontinuous processes and redundancies will increase the economic burdens in the health care system. The latest developments and appropriate logistic premises nowadays offer a realistic basis for implementing telemonitoring as a central service and information tool as well as an instrument controlling the information- and data-flow between patient, hospital and medical practitioner.

Haemodynamic investigations were performed in 40 patients with acute myocardial infarction before and after intravenous application of 6 mg propranolol. Cardiac index was significantly decreased caused by reduction of cardiac frequency and stroke volume. Pulmonary capillary pressure increased significantly. As a consequence pulmonary and peripheral vascular resistance increased. Arterial blood pressure remained largely unaffected. Propranolol showed a haemodynamically beneficial decrease of left ventricular stroke work without signs of negative cardiodepression at a cardiac index of more than 3.0 l/min . m2. At a cardiac index of less than 3.0 l/min . m2 a haemodynamically detrimental lowering of cardiac index to ranges of insufficiency of 2.0 l/min . m2 on average occurred. Thus cardiac index is an important factor for the decision of use of beta-blocking agents in acute myocardial infarction. Indiscriminate use of beta-blocking substances should not be accepted.

Background: The identification of patients at increased risk for ventricular tachycardia or ventricular fibrillation (VT/VF) and sudden cardiac death has consequences for therapeutic options and thus may reduce mortality in patients with coronary artery disease (CAD). Hypothesis: We hypothesized that the intra-QRS fragmentation in magnetocardiographic recordings is increased in patients with CAD and with a history of VT/VF. Methods: Multichannel magnetocardiography (MCG) was carried out in 34 healthy controls, 42 patients with CAD without a history of VT/VF, and 43 patients with CAD and with a history of VT/VF. The intra-QRS fragmentation was quantified by a new fragmentation score. Its spatial distribution was investigated using two-dimensional (2-D) contour maps according to the sensor position of the 49-channel magnetogradiometer. Results: Patients with CAD and with a history of VT/VF had significantly increased QRS fragmentation compared with patients with CAD without VT/VF or controls (72.9 ± 37.5,48.5 ± 14.3, and 42.5 ± 7.8, respectively; p< 0.05). The area of high fragmentation in 2-D contour maps was twice as large in patients with than in those without a history of VT/VF (represented by the number of MCG channels with high fragmentation: 26.3 ± 15.5 vs. 12.4 ± 9.9, p

The variability of electric and magnetic signals from the heart during the depolarization phase is investigated. A signal processing method is developed, which provides estimates for the beat-to-beat variability of the QRS-complex. The method is based on the decomposition of the depolarization signal into bandpass signals by means of the Morlet wavelet transform. The beat variability of the depolarization signal is estimated by normalized variances of the envelope and instantaneous frequency of bandpass signals. Time intervals of the bandpass filtered depolarization signals having a high signal-to-noise ratio are selected applying an analysis based on phase statistics. The method was tested by computer simulation and experimental data taken from electrocardiographic and magnetocardiographic measurements of healthy persons and patients prone to malignant ventricular tachycardia (VT) or ventricular fibrillation (VF). Results suggest that the calculated variance parameters permit the characterization of beat variable depolarization signals and distinguish VT/VF patients from healthy persons.

Die Variabilitat des Herzsignals wahrend der Depolarisationsphase wird untersucht. Die entwickelte Signalverarbeitungsmethode liefert Kennwerte zur Bestimmung der Schlag-zu-Schlag-Variabilitat des Depolarisationssignals. Die Methode basiert auf der Dekomposition des Depolarisationssignals in Bandpasssignale mittels der Morlet-Wavelet-Transformation. Die Schlagvariabilitat wird durch die normalisierten Varianzen von Einhullender und Momentanfrequenz der Bandpasssignale bewertet. Ausgewertet werden Signalbereiche mit grosem Signal-/Rauschleistungsverhaltnis. Die erforderliche Selektion leistet ein Signalverarbeitungsalgorithmus, der die Phasenvarianz von Bandpasssignalen berechnet. Mit der Methode wurden Elektrokardiogramme und Magnetokardiogramme von Infarktpatienten analysiert. Die Resultate weisen signifikante Unterschiede zwischen der Patienten- und Kontrollgruppe aus. Die entwickelte Methode zur Einzelschlaganalyse von Herzsignalen liefert zusatzliche Information zu abnormalen Herzpotentialen, die durch Auswerteverfahren, die auf einer Signalmittelung basieren, unterdruckt wird.

The spread of electrical endo- and epicardial activation is projected also to body surface and can be deducted from various numbers of recording points at the front or the back of the thorax. The resulting data are visualized in a body surface map (BSM). To characterize this activation, the amplitudes are measured and then evaluated according to the origin, the position of the extrema, and the zero line between them. To minimize the BSM data during the activation cycle, the area underneath the QRS complex and/or the ST-T wave may be calculated and plotted as an iso-area BSM. Similarities between the various BMSs are evaluated either by visual comparison or by means of correlation algorithms. The results exceeded the precision of standard ECG recordings in measuring de- and repolarization. Comparison between a succession of paced maps resulted in the precise localization of arrhythmogenic sources. Due to the inhomogeneities of the human thorax direct measurement of the position of an electric source, e.g., the focus of ventricular tachycardia or extrasystole, has not yet been accomplished. Magnetocardiographic mapping, a novel method to record the heart‘s magnetic field, however, allows for direct measurement of the arrhythmic origin since this method is not sensitive to these inhomogeneities. Various examples of the clinical application of BSM have been described in this paper and their results discussed.

The ectopic atrial tachycardia is diagnosed in approx. 10 to 15% of supraventricular tachycardias. Since medical therapy is often shown to be ineffective, ablative procedures became especially important in this disease. Localization of the arrhythmia foci seems to be concentrated at anatomical preformations like the crista terminalis, right or left atrial appendage orifice or at the superior pulmonary veins. The P-wave vector in the surface ECG is predictive for focus localization: a positive or biphasic P-wave in a VL for right atrial foci, a positive P-wave in V1 for left atrial foci. Catheter ablation therapy is also shown to be very effective in this kind of supraventricular tachycardia.

Fragmentierte und verzogerte Aktivierung des ventrikularen Myokards kann die Ursache fur maligne tachykarde Herzrhythmusstorungen sein. Durch den Nachweis ventrikularer Spatpotentiale wird nur eine sehr stark verzogerte Depolarisation, nicht aber die Intra-QRS-Aktivierung erfast. Ziel dieser Untersuchung war es daher, die gesamte Phase der ventrikularen Depolarisation zu untersuchen, eine abnorme elektrische Aktivierung magnetokardiographisch zu erfassen und zu quantifizieren sowie an einem kleinen Kollektiv koronarkranker Patienten die prognostische Bedeutung abzuschatzen.

The German Competence Network on Atrial Fibrillation (AFNET) is a national interdisciplinary research network funded by the Federal Ministry of Education and Research (BMBF). AFNET was initiated in 2003 and aims at improving treatment of atrial fibrillation (AF), the most frequent sustained cardiac arrhythmia. AFNET has established a nationwide patient registry on diagnostics, therapy, course and complications of AF in Germany. The data analyzed to date demonstrate that patients with AF are likely to have multiple co-morbidities, such as hypertension, valvular heart disease, coronary artery disease, diabetes mellitus and advanced age. Oral anticoagulation is provided to the majority of patients in accordance with the recommendations given by guidelines. Further areas of research deal with the optimal duration of antiarrhythmic therapy following electrical cardioversion of atrial fibrillation and the value of strategies to prevent arrhythmogenic changes, such as fibrosis in the atria, for prevention of further episodes of atrial fibrillation. Additional registry projects were established for patients with catheter-based interventional therapy of atrial fibrillation and surgical ablation to define success, complications and long term results of these recently developed procedures more clearly. Data and insights gathered from these projects were used to further develop standards of care in two international conferences.

Cardiac arrhythmias can be treated by endocardial laser photocoagulation of arrhythmogenic foci. Transcatheter continuous wave Nd-YAG laser (1064 nm) photocoagulation was studied for impairment of atrioventricular (AV) conduction. First, studies on the dose-effect relation revealed that in vitro applications to ventricular endocardium produce dose-dependent coagulation necrosis. However, energy absorption varies in tissue specimens from different experimental animals and humans and may be dependent on differences in surfaces ultrastructure. Ten times more energy is required for human endocardial specimens than for canine endocardium. The long-term in vivo experiment demonstrates that the chronic laser-induced myocardial lesion size is proportional to the applied energy, exhibit no arrhythmogenic effects and may thus be suitable for the treatment of cardiac arrhythmias. Transcatheter laser application using a combined electrode-laser catheter reliably achieved a slowing of atrioventricular AV conduction (AV modification) or a complete AV block. Thus, the transcatheter application of Nd-YAG laser energy at the AV node may be useful for treatment of tachyarrhythmias in man.

The changes in the demographic structure, the increasing multi-morbidity in connection with a rise in the number of chronic illnesses and the absence of an effective coordination of the different levels of health care services with its discontinuous processes and redundancies will increase the economic burdens in the health care system. The latest developments and appropriate logistic premises nowadays offer a realistic basis for implementing telemonitoring as a central service and information tool as well as an instrument controlling the information- and data-flow between patient, hospital and medical practitioner.

Progression of chronic heart failure depends on various additional pathophysiologic factors like blood pressure, arrhythmias, congestion. Early detection of any alteration using telemonitoring of multiple vital parameters may avoid severe decompensation requiring hospital admission. The feasibility and the clinical outcome using a new telemonitoring device for recording multiple vital parameters and allowing communication on individual state of health is investigated. Twenty-four patients with chronic heart failure (mean age 65 years, mean LV ejection fraction 35%) requiring at least one hospital admission during the past year were investigated. Twice a day, the vital-parameters were measured (weight, blood pressure, heart rate and rhythm, oxygen saturation, respiration rate) and patients information on well being, shortness of breath, medication, and request for contact were received. Intra-individual comparison was carried out between the 12 month before inclusion in this study and 12 month under telemonitoring surveillance (extrapolated, if necessary). Performing over 10 500 measurements during 5751 patient days, critical events were diagnosed for 55 events concerning relative weight gain (43 episodes), blood pressure (6), decrease in oxygen saturation (3), new onset of atrial fibrillation with tachyarrhymia (3). Of these, 45 events were controlled on an outpatient basis by changing medication or external cardioversion. Only 10 patients required re-admission. Thus, the number of admission to the hospital could be reduced by 62%, those of days spent in hospital by 69%. Non-invasive telemonitoring of multiple vital parameters combined with patients statements on their health condition and out-patient treatment on the basis of these findings is found to be an effective and reliable approach to avoid hospital readmission for patients with chronic heart failure.

The experience with an information system network using the "Cardiology Information System" in the Cardiopulmonary Department of a University Clinic are reported here. From decentralized work stations the results of various clinical investigations are documented and put together for complete documentation and quality control. For 3,000 invasive studies various parameters were investigated. Mean radiation time for diagnostic catheterization was 10.9/spl plusmn/8 min. If PTCA was performed immediately after the diagnostic procedure the radiation exposure was less than in case the PTCA was performed electively (p >

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. >

A complex binomial bandpass filter is suggested for the analysis of ECG and MCG signals. Theoretical background and details of the appropriate design of these filters are given. Application of these digital filters on ECG/MCG signals provide bandpass signals. Envelope and phase of these signals are used for analysing high frequency components in cardiac signals. Phase variance changes are used to select time intervals dominated by cardiac activity. Mean and variance of the envelope characterize the regularity of the depolarisation process. Two parameters derived from these quantities are used to separate MCGs of patients suffering from ventricular arrhythmia from MCGs of healthy persons. >

A reference standard for testing interpreting electrocardiographs and their underlying algorithms has been developed. It consists of ECG signals of superior quality and comprehensive additional information stored in a relational data base which is accessible via the Internet.

Bandlimited high frequency signals can be described by their envelope and phase. Complex binomial bandpass filters are an appropriate tool to generate bandlimited cardiac signals used for analysing envelope and phase. A signal processing method is suggested to evaluate signal changes of envelope and phase from beat to beat. Two parameters relied on variance of envelope and current frequency (derivative of the phase) were derived to assess the regularity of cardiac high frequency components within a frequency range of interest. They can be used to separate cardiac signals of patients suffering from ventricular arrhythmia from cardiac signals of healthy persons.

The authors' have studied the group of 12 patients suffering from the Wolf-Parkinson-White (WPW) syndrome. The noninvasive magnetocardiographic (MCG) mapping data were used to find a functional localization of accessory conduction pathway (AP) by using the current dipole source model in different volume conductor models. The best reference interval for magnetic data baseline corrections as well as the onset of AP were determined automatically by means of averaged standard deviation of magnetic recordings. The stability of MCG inverse solutions has been studied. For all cases the calculated AP spatial coordinates were compared to corresponding results obtained by the invasive electrophysiological study (EPS).

Bei der Diagnostik von Rhythmusstorungen spielt neben den invasiven Verfahren (siehe Richtlinien fur die Durchfuhrung invasiver elektrophysio-logischer Untersuchungen der Deutschen Gesellschaft fur Kardiologie — Herz- und Kreislaufforschung) die nichtinvasive Diagnostik eine wichtige Rolle. Diese nichtinvasive Diagnostik stutzt sich heute vorwiegend auf vier Untersuchungsverfahren: Langzeit-Elektrokardiographie, die Untersuchung mit Hilfe sogenannter Event-Recorder, die Kipptischuntersuchung sowie die Durchfuhrung pharmakologischer Testverfahren. Die hier von der Arbeitsgruppe Arrhythmie der Deutschen Gesellschaft fur Kardiologie — Herz- und Kreislaufforschung vorgelegte Empfehlung zur Durchfuhrung dieser nichtinvasiven Untersuchungsverfahren soll einen Uberblick uber die apparativen Voraussetzungen sowie die Indikation bei verschiedenen Arrhythmien bzw. Krankheitsbildern geben. Jedes Kapitel endet mit einer Empfehlung zur Indikation, wobei diese Empfehlungen entsprechend den Richtlinien zur Durchfuhrung invasiver elektrophysiologischer Untersuchungen in drei Kategorien unterteilt werden: A Indikation, bei der weitgehender Konsens besteht; B Mogliche Indikation, bei der aber kein allgemeiner Konsens aufgrund des gegenwartigen wissenschaftlichen Erkenntnisstandes besteht; C Keine Indikation.

Magnetocardiography was introduced to clinical cardiologists in the early 1970’s. The measurement devices were technically unreliable, signal-to-noise ratio was poor and measurements were time consuming. Most measurements were performed in ambient environment without any shielding. Patient material studied included at first normals and myocardial infarction patients. Electromagnetic activity produced by the His-Purkinje conduction system also drew a lot of attention. Later on, pregnant women (fetal MCG), patients with ventricular hypertrophy, Wolff-Parkinson-White (WPW) Syndrome patients as well as patients with tachycardias were studied. The analysis of MCG signals in those days was rather primitive: mostly descriptive, qualitative, and morphological data was published. In order to be useful in the clinic there were many things to be improved: low signal-to-noise ratio, limited mapping and analysis possibilities, and the measurement systems were mostly located outside hospital.

The WolfF-Parkinson-White (WPW) Syndrome is characterized by the accessory conduction pathway (AP) of excitation between atria and ventricles. To find a functional localization [1, 2] of the AP, noninvasive magnetocardiographic (MCG) mapping data were used with the current dipole source in different volume conductor models.

It has been shown that regional ventricular repolarization properties can be reflected in body surface distributions of electrocardiographic QRST deflection areas (integrals). We hypothesize that these properties can be reflected also in the magnetocardiographic QRST areas and that this may be useful for predicting vulnerability to ventricular tachyarrhythmias. Magnetic field maps were obtained during sinus rhythm from 49 leads above the anterior chest in 22 healthy (asymptomatic) control subjects (group A) and in 29 patients with ventricular arrhythmias (group B). In each subject, the QRST deflection area was calculated for each lead and displayed as an integral map. The mean value of maximum was significantly larger in the control group A than in the patient group B (1,626+/-694 pTms vs. 582+/-547 pTms, P

The structure of high-frequency components of electric and magnetic signals from the heart during the depolarisation phase is investigated. After averaging and broadband filtering with a binomial bandpass filter (37 Hz-90 Hz), the fragmentation of the QRS-complex is quantified. The number of extrema M and a new score value S are calculated from the signals of three electrical leads and one magnetic lead of 23 healthy subjects, 23 patients with coronary heart disease (CHD) without reported event of ventricular tachycardia or fibrillation at the time of measurement, and eight patients with CHD who have suffered from malignant tachycardia. For the parameter M, the sensitivity and specificity for healthy subjects against patients with CHD and ventricular tachycardia for the magnetic lead (the best electric lead) are 100% (75%) and 100% (100%). For the magnetic lead (best electric lead) and parameter S, the sensitivity and specificity are 100% (75%) and 95.6% (100%).

The spatial distribution of high-frequency components in magnetic signals during the QRS complex of the human heartbeat was investigated. Cardiomagnetic signals were recorded simultaneously using 49 first-order magnetogradiometer channels of a multi-SQUID system with a low noise power density. The QRS fragmentation score S, as a measure of the fragmentation of the bandpass-filtered QRS complex, was examined for its sensitivity and specificity to discriminate 34 healthy volunteers, 42 post-myocardial infarction patients and 43 patients with coronary heart disease and with a history of malignant sustained ventricular tachycardia or ventricular fibrillation. The multichannel information was visualized by two-dimensional mapping of the score values of the single channels. By averaging the score values for the seven central channels, S7, the score values of all 49 channels, S49, and calculating the standard deviation for all 49 channels, D49, a higher sensitivity and specificity for detecting patients with ventricular tachycardia (VT) or ventricular fibrillation (VF) was reached than by analysis of a single channel. Combination of these parameters furnishes a sensitivity of 90% and a specificity of 70% for identifying patients prone to VT/VF. The results were compared with diagnostic information obtained from the QRS duration of the signal as well as with results obtained by modified QRS integral mapping.

Fragmented and delayed activation of ventricular myocardium can cause malignant tachyarrhythmias. By detection of ventricular late potentials only a severely delayed depolarisation is registered, but not the intra QRS-activation. The aim of this study was to examine the complete phase of ventricular depolarisation, to detect and to quantify abnormal electrical activation by magnetocardiography and to estimate in a small group of patients with coronary heart disease the prognostic significance.In 26 healthy subjects, 32 patients after myocardial infarction without malignant ventricular arrhythmias and 10 patients with coronary heart disease and a history of sustained, monomorph ventricular tachycardia magnetocardiography was performed in a magnetically shielded room. To quantify the fragmentation of QRS a fragmentation-index (FI) was calculated. Besides signal averaged ECG, in patients with coronary heart disease cardiac catheterisation and in patients with arrhythmias electrophysiological testing was performed. The FI for the three groups was significantly different (p0,005). The mean FI in the group of healthy subjects was 20,4+/-5,4, in the group of postinfarction-patients without arrhythmias 27+/-12,1 and in the group of patients with coronary heart disease and ventricular arrhythmias 49,5+/-17,9. Dichotomized at 36 the sensitivity was 80%, the specifity 93%, the positive predictive value was 66% and the negative predictive value 96%. The FI was correlated to the extent of regional wall-motion-irregularity and global ejection fraction.Analyzing late potentials, the values for sensitivity and positive predictive value were surprisingly low (20% and 50%, respectively). The specifity was 96%, the negative predictive value was 88%. Calculating the FI on the basis of electrical signals only an insufficient discrimination of the groups was possible.In the follow-up period of two years one post-infarctional patient was resusciated because of ventricular fibrillation. The FI of this patient was 17.One patient with coronary 3-vessel-disease and left ventricular ejection fraction of 50% died due to acute myocardial infarction, his FI was 39.By means of magnetocardiography fragmented ventricular activation in patients with coronary heart disease was demonstrated even within the QRS-complex and could be correlated to ventricular tachyarrhythmias.

Magnetocardiogruphic mapping opens new perspectives for three-dimensional localization of cardiac electrical activation. Using a 37-channel SQUID magnetometer equipment with high shielding, the origin of abnormal ventricular aclivalion was investigated in 18 patients ivith Wolff-Parkinson-White syndrome prior to catheter ablation and in 5 of 31 patients with coronary artery disease having a sufficient number of monomorphic ventricular extrasystoies to enable evaluation. In ali WPW-patients, the site of the earliest dello-wave activation was projected onto the AV-valve plane in accordance with the MR images. The result of magnetocardiographic localization was then compared to the site of successful catheter oblation delermined by digital imaging processing. After optimization of the algorithms, both sites were in the various planes at the foliowing distance from each other; X-plane; 0.8 ± 0.9 cm, Y-pIane; 1.1 ± 1.0 cm and Z-piane; 1.5 ± 1.0 cm. In three-dimensional projection, the mean difference in space between both positions was calculated to be 2.1 ± 1.7 cm. After this vahdofion ventricular premature beats were localized in another group of patients. In 4 of 5 palienfs their origin was found at the border of infarct areas. In each case, the progression of the ventricular activation couid be pursued. The detected structure of the magnetic field distribution of the VBP's exhibited a stable bipolar patlern, which is comparable to that of venlricuiar tachycardia, and its algorithms may be used to localize the origin of ventricular lachycardia. Thus, non-invasive magnetocardiographic mapping localizes abnormal ventricuiar activations with fair accuracy, which makes it an useful adjunct for invasive investigations as well as studies of the pathophysiology of arrhythmias.

BACKGROUND Previous studies report a morning peak in the occurrence of out-of-hospital sudden cardiac death but lack detailed information on underlying arrhythmias. We used the documentation system of the semiautomated defibrillators used by emergency medical technicians to investigate the circadian pattern of defined arrhythmias and the influence of demographic patient characteristics on this pattern. METHODS AND RESULTS From December 1988 to December 1990, 703 consecutive patients (63% men; age, 67 +/- 17 years) with sudden cardiac death were registered in the Klinikum Steglitz area of the Berlin emergency care system. Determination of time of day of the event was based on the arrival time of the rescue squad. A marked circadian variation (P < .0001) in the occurrence of sudden cardiac death was observed with a primary morning peak (6 AM to noon) and a secondary afternoon peak (3 to 7 PM). The subgroup of 294 patients with ventricular fibrillation as initially documented arrhythmia showed a similar circadian variation (P < .0001). In significant contrast (P < .01), patients with asystole (n = 260) or pulseless bradyarrhythmias (n = 149) were more evenly distributed during the daytime with a primary night trough. Multivariate logistic regression analysis revealed that the circadian pattern of ventricular fibrillation was similar in both gender groups but tended to differ with regard to age: patients older than 65 years demonstrated a monophasic distribution, whereas patients aged 65 years or less had a biphasic distribution with peaks in the morning and in the afternoon. CONCLUSIONS The circadian pattern of sudden cardiac death reflects primarily a circadian variation in onset of ventricular fibrillation. The different circadian patterns of ventricular fibrillation, pulseless bradyarrhythmias, and asystole suggest different pathophysiological mechanisms of causation of death. The age dependence of the pattern of ventricular fibrillation may indicate different underlying external or endogenous triggers.

Early defibrillation by emergency medical technicians or even less qualified personnel has been shown to improve survival rates for out-of-hospital cardiac arrest caused by ventricular fibrillation. It has been questioned whether these favourable results can be applied within the context of physician-attended emergency medical systems. Taking into consideration the results of a pilot study and after a careful analysis of the logistic and epidemiological background, the first German EMT-D program was introduced in the former West Berlin in December 1988. The first 2 years of experience with 499 technician-initiated resuscitation attempts in which the mobile intensive care unit of Klinikum Steglitz was involved, confirmed the results of the pilot study with an improved long-term survival rate (18%) for patients with ventricular fibrillation. We conclude that EMT defibrillation should be introduced in emergency physician-attended two-tiered emergency medical systems, whenever a thorough analysis of the existing rescue systems exhibits a ‘relevant frequency’ of resuscitation and response interval of 15 min or less.