Rahul Agrawal

Beneficial effects of pravastatin (±colestyramine/niacin) initiated immediately after a coronary event (the randomized lipid-coronary artery disease [L-CAD] Study)

Secondary prevention of coronary heart disease by antilipidemic therapy beginning at > or =3 months after an acute coronary syndrome is well documented. The impact, however, of immediate initiation of antilipidemic therapy on coronary stenoses and clinical outcome in patients with acute coronary syndrome is unknown. In our study, patients were randomized, on average, 6 days after an acute myocardial infarction and/or percutaneous transluminal coronary angioplasty secondary to unstable angina, to pravastatin (combined, when necessary, with cholestyramine and/or nicotinic acid) to achieve low-density lipoprotein cholesterol levels of < or =130 mg/dl (group A, n = 70). In controls (group B, n = 56), antilipidemic therapy was determined by family physicians. Quantitative coronary angiography was performed at inclusion, and at 6- and 24-month follow-up. The combined clinical end points were total mortality, cardiovascular death, nonfatal myocardial infarction, need for coronary intervention, stroke, and new onset of peripheral vascular disease. Minimal lumen diameter in group A increased by 0.05 +/- 0.20 mm after 6 months and 0.13 +/- 0.29 mm after 24 months, whereas it decreased by 0.08 +/- 0.20 mm and 0.18 +/- 0.27 mm, respectively, in group B (p = 0.004 at 6 months and p <0.001 at 24 months). After 2 years, 29 patients of 56 patients in group B, but only 16 of 70 patients in group A, experienced a clinical end point (p = 0.005; odds ratio 0.28, confidence intervals 0.13 to 0.6). We conclude that pravastatin-based therapy initiated immediately after an acute coronary syndrome is well tolerated and safe, lessens coronary atherosclerosis, and has a pronounced clinical benefit.

Improvement of endocardial border delineation in suboptimal stressechocardiograms using the new left heart contrast agent SH U 508 A

Recent studies have shown that the saccharide based echocardiographic contrast agent SH U 508 A opacifies the left ventricle after i.v. injection, thus possibly improving endocardial border definition. This study was performed to determine whether SH U 508 A can enhance the wall motion analysis in suboptimal echocardiographic images at rest and following pharmacological stress. Ten male patients (mean 58 years) exhibiting ≥30% endocardial border dropout were examined prior to a diagnostic left heart catheterization. Five patients were stressed with Dobutamine, 5 with Dipyridamole. The wall motion was assessed visually (qualitatively) as well as computer-aided (quantitatively). The concordance between left ventricular angiography as ‘gold standard’ and resting echocardiography regarding the wall motion analysis was significantly improved from 64.5% to 90.3% following the injection of SH U 508 A (p < 0.05). A delineation score (0 = not delineated, 1 = delineated) of 12 individual wall segments was used. The mean delineation score at baseline was 6.1 ±1.4 at rest and 6.6 ±1.9 during stress. SH U 508 A significantly (p < 0.01) increased the score to 9.6 ±1.9 and 10.3 ±1.7, respectively. The intraobserver variability for assessing the delineation score was significantly (p < 0.04) improved by SH U 508 A. SH U 508 A, however, did not improve the quantitative assessment of the left ventricular function. Only 40% of the patients could be analyzed following SH U 508 A injection. No severe adverse reactions were seen. SH U 508 A led to a significant, clinically important, improvement in the interpretation of stress echocardiograms in patients with inconclusive routine echocardiograms.

Magnetocardiographic analysis of the two-dimensional distribution of intra-QRS fractionated activation

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.

Value of magnetocardiographic QRST integral maps in the identification of patients at risk of ventricular arrhythmias.

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 < 0.0001). To quantitatively assess intragroup variability in the control group A and intergroup variability of the control and patient groups, we used the correlation coefficient r and covariance σ. These indices showed significantly less intragroup than intergroup variation (e.g., in terms of σ, 28.0 · 10−6± 12.3 · 10−6 vs 3.4 · 10−6± 12.5 · 10−6, P < 0.0001). Each QRST integral map was also represented as a weighted sum of 24 basis functions (eigenvectors) by means of Karhunen‐Loeve transformation to calculate the contribution of the nondipolar eigenvectors (all eigenvectors beyond the third). This percentage nondipolar content of magnetocardiographic QRST integral maps was significantly higher in the patient group B than in the control group A (13.0%± 9.1% vs 2.6%± 2.0%, P < 0.0001). Discriminations between control subjects and patients with ventricular arrhythmias based on magnitude of the maximum, covariance σ, and nondipolar content were 90.2%, 90.2%, and 86.3% accurate, with a sensitivity of 89.7%, 93.1%, and 75.9%, and a specificity of 90.9%, 86.4%, and 100%. We have shown that magnitude of the maximum and indices of variability and nondipolarity of the magnetocardiographic QRST integral maps may predict arrhythmia vulnerability. This finding is in agreement with earlier studies that used body surface potential mapping and suggests that magnetic field mapping may also be a useful diagnostic tool for risk analysis.

The impact of vessel and catheter position on the measurement accuracy in catheter-based quantitative coronary angiography

Background: The calculation of absolute artery dimensions in quantitative coronary angiography is usually carried out by catheter calibration. It is based on the proportional comparison of the dimension of the imaged artery segment to the dimension of the imaged angiographic catheter of known size. This calibration method presumes an identical radiographic magnification between angiographic catheter and artery segment of interest. However, due to the different intrathoracic location of both objects the radiographic magnification or calibration factor is often not identical for a given angiographic projection. The aim of this study was to quantify the magnification error (out-of-plane magnification error) for the major coronary artery segments imaged in frequently used angiographic projections. Methods The intrathoracic spatial location of 468 coronary segments (RCA 196, LAD 156, LCX 116) and their respective coronary catheters were established with biplane angiography and known imaging geometry data. The error in the radiographic magnification or calibration factor was then calculated for all 936 monoplane projections using the spatial coordinates and imaging geometry data. Results The mean magnitude of magnification error was 4% within all 936 measurements. The magnitude and direction of error varied with the lesion localization and the angiographic projection angle (range −12.6% to +10.6%). The error characteristics could be described with six typical error groups by stratifying the data according to the three main coronaries and two angiographic planes. In 24% of measurements, the magnification error exceeded the 5.2% error limit acceptable for reference vessel sizing. Measurements of left coronary arteries were mainly affected by it. Conclusion: The magnification error contributes to the calibration error in measuring arterial dimensions by quantitative angiography. This error may affect the reliability of clinical studies and the proper sizing of interventional devices. These findings could be used to improve current error correction algorithms in order to reduce the effect of the magnification error in measuring arterial dimensions.

Factors influencing the diagnostic accuracy of dobutamine stress echocardiography

Background: While Dobutamine stress echocardiography is a well established tool, the range of the diagnostic accuracy found in the literature is rather large. The main reason for this is the fact, that different test protocols were used. Aim of this study was to assess the effects of both addition of atropine as well as consideration of a hyperdynamic response while interpreting the stress echocardiogram on the diagnostic accuracy. Methods and results: 120 consecutive patients were examined and divided into the following groups: A) achieving their age predicted heart rate with dobutamine, B) termination of the test due to ischemia, C1) negative test without reaching the predicted heart rate, and C2) C1 following addition of atropine. All of the echocardiograms were analyzed twice: 1) regarding the lack of a hyperdynamic response to dobutamine as ischemia (Hyper analysis), and 2) ignoring the hypercontractility (Conventional analysis). The accuracy of A and B were 88% and 90% resp. Group C1 had a very poor accuracy of 60%. This rose significantly (p < 0.01) after atropine (C2 = 84%), without leading to an increase of adverse effects. Conventional wallmotion analysis lead to an overall accuracy of 87% (groups A, B, and C2), while Hyper analysis showed an accuracy of 90% (p < 0.01). Conclusions: To achieve a high accuracy Dobutamine stress echocardiography should always be combined with atropine to reach a target heart rate. The wallmotion analysis should be based on the assumption that a hyperdynamic response to dobutamine is normal, while its lack is indicative of ischemia.

Magnetkardiographischer Nachweis abnormer intraventrikulärer Erregungsausbreitung bei ischämie-bedingter Herzerkrankung ohne und mit Tachykardien

UNLABELLED 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 (p<0,005). 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. CONCLUSION 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.ZusammenfassungFragmentierte und verzögerte Aktivierung des ventrikulären Myokards kann die Ursache für maligne tachykarde Herzrhythmusstörungen sein. Durch den Nachweis ventrikulärer Spätpotentiale wird nur eine sehr stark verzögerte Depolarisation, nicht aber die Intra-QRS-Aktivierung erfaßt. Ziel dieser Untersuchung war es daher, die gesamte Phase der ventrikulären Depolarisation zu untersuchen, eine abnorme elektrische Aktivierung magnetokardiographisch zu erfassen und zu quantifizieren sowie an einem kleinen Kollektiv koronarkranker Patienten die prognostische Bedeutung abzuschätzen.Bei 26 Gesunden, 32 Patienten nach akutem Myokardinfarkt ohne maligne ventrikuläre Arrhythmien und 10 Patienten mit koronarer Herzkrankheit und anhaltender, monomorpher ventrikulärer Tachykardie in der Anamnese wurde in einem magnetisch abgeschirmten Raum eine Magnetokardiographie mittels Superconducting Quantum Interference Device (SQUID)-Elementen durchgeführt. Zur Quantifizierung der fragmentierten Aktivierung im QRS wurde ein Fragmentations-Index (FI) berechnet. Bei jedem Patienten bzw. Gesunden wurde außerdem ein hochverstärktes EKG zur Analyse von Spätpotentialen, bei den Patienten mit koronarer Herzkrankheit eine Herzkatheteruntersuchung und bei den Patienten mit ventrikulären Herzrhythmusstörungen eine elektrophysiologische Untersuchung durchgeführt.Es ergaben sich für die drei Gruppen hochsignifikant unterschiedliche Werte für den FI (p<0,005). Der mittlere FI in der Gruppe der Gesunden betrug 20,4±5,4, in der Gruppe der Postinfarkt-Patienten ohne Arrhythmien 27,2±12,1 und in der Gruppe der Patienten mit koronarer Herzkrankheit und ventrikulären Tachykardien 49,5±17,9. Bei einem Schwellenwert von 36 ergab sich eine Sensitivität von 80%, eine Spezifität von 93%, ein positiv prädiktiver Wert von 66% und ein negativ prädiktiver Wert von 96% bezüglich des Auftretens einer anhaltenden ventrikulären Tachykardie. Der Fragmentations-Index war korreliert mit dem Ausmaß der regionalen Wandbewegungsstörungen und der globalen linksventrikulären Ejektionsfraktion.Bei der Spätpotentialanalyse ergaben sich überraschend niedrige Werte für Sensitivität (20%) und positiv prädiktiven Wert (50%) bei einer Spezifität von 96% und einem negativ prädiktiven Wert von 88%. Bei der Errechnung des FI aus den elektrischen Signalen konnten die drei Gruppen nur unzureichend unterschieden werden.In der 2-jährigen Nachverfolgungsperiode der Postinfarkt-Patienten erlitt ein Patient Kammerflimmern und konnte erfolgreich reanimiert werden. Der FI dieses Patienten betrug 17.Ein Patient mit koronarer 3-Gefäß-Erkrankung verstarb an einem akuten Myokardinfarkt. Sein FI betrug 39.Schlußfolgerung: Mittels der Magnetokardiographie konnte eine fragmentierte ventrikuläre Aktivierung bei Patienten mit koronarer Herzkrankheit auch im QRS-Komplex nachgewiesen werden und zu abgelaufenen ventrikulären Tachykardien korreliert werden.SummaryFragmented 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 (p<0,005). 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.Conclusion: 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.

Magnetokardiographisches Mapping: QT Dispersion bei Patienten mit koronarer Herzkrankheit mit und ohne ventrikuläre Tachykardien

Eine Dispersion der QT-Zeit, die im Oberfl~ichen EKG gemessen wird, wurde sowohl fa Gesunde als auch fa verschiedene Erkrankungen beschrieben. Eine erh6hte QT Dispersion fiel z.B. bei Patienten mit koronarer Herzkrankheit, Patienten mit Dilatativer Kardiomyopathie, Hypertropher Kardiomyopathie und bei Patienten mit Long QT-Syndrom auf (t, 2, 3, 4, 5). Experimentell konnte an Langendorff-perfundierten Kaninchenherzen eine Ubereinstimmung der QT Dispersion epikardialer monophasischer Aktionspotentiale mit Elektrogrammen ira Oberfl~chen-EKG gezeigt werden (6). Demzufolge scheint die QT Dispersion im Oberfl/ichen-EKG ein Korrelat der lokal inhomogenen Repolarisation bei bestimmten Patienten zu sein. So wie ein Zusammenhang zwischen expe¡ nachgewiesener Inhomogenit/~t der Repola¡ und erh6hter ventrikul~rer Vulnerabilit~it besteht (6, 7, 8), konnte in klinischen Studien eine erh6hte QT Dispersion ira Oberfl~ichenEKG als Risikofaktor fa ventrikul/ire Arrhythmien ausgemacht werden (9). Allerdings ist die Bestimmung der QT Dispersion problematisch (10). Es ergeben sich vor allem bei der Festlegung des T-Wellen Endes Schwierigkeiten, wenn die T-Welle flach oder biphasisch ist oder wenn sich eine U-Welle anschliel3t. Die Magnetokardiographie ist ein relativ neues Verfahren, mit dem das voto Herzen ausgehende magnetische Feld bera bestimmt wird. Mit einem Mehr-Kanal-System l~iBt sich ohne viel Aufwand ein pr5kordiales Mapping mit im Vergleich zum 12-Kanal EKG hoher r~iumlicher Aufl6sung durchfa Ziel di• Studie war es, di• Wertigkeit der QT Dispersion nach magnetokardiographischen Multi-Kanal-Mapping an Patienten mit koronarer Herzkrankheit mit und ohne ventrikul~ire Tachykardien sowie an einem Kontrollkollektiv zu a252

Magnetcardiographic detection of abnormal intraventricular activation in patients with ischemic heart disease with and without tachycardia

UNLABELLED 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 (p<0,005). 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. CONCLUSION 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.ZusammenfassungFragmentierte und verzögerte Aktivierung des ventrikulären Myokards kann die Ursache für maligne tachykarde Herzrhythmusstörungen sein. Durch den Nachweis ventrikulärer Spätpotentiale wird nur eine sehr stark verzögerte Depolarisation, nicht aber die Intra-QRS-Aktivierung erfaßt. Ziel dieser Untersuchung war es daher, die gesamte Phase der ventrikulären Depolarisation zu untersuchen, eine abnorme elektrische Aktivierung magnetokardiographisch zu erfassen und zu quantifizieren sowie an einem kleinen Kollektiv koronarkranker Patienten die prognostische Bedeutung abzuschätzen.Bei 26 Gesunden, 32 Patienten nach akutem Myokardinfarkt ohne maligne ventrikuläre Arrhythmien und 10 Patienten mit koronarer Herzkrankheit und anhaltender, monomorpher ventrikulärer Tachykardie in der Anamnese wurde in einem magnetisch abgeschirmten Raum eine Magnetokardiographie mittels Superconducting Quantum Interference Device (SQUID)-Elementen durchgeführt. Zur Quantifizierung der fragmentierten Aktivierung im QRS wurde ein Fragmentations-Index (FI) berechnet. Bei jedem Patienten bzw. Gesunden wurde außerdem ein hochverstärktes EKG zur Analyse von Spätpotentialen, bei den Patienten mit koronarer Herzkrankheit eine Herzkatheteruntersuchung und bei den Patienten mit ventrikulären Herzrhythmusstörungen eine elektrophysiologische Untersuchung durchgeführt.Es ergaben sich für die drei Gruppen hochsignifikant unterschiedliche Werte für den FI (p<0,005). Der mittlere FI in der Gruppe der Gesunden betrug 20,4±5,4, in der Gruppe der Postinfarkt-Patienten ohne Arrhythmien 27,2±12,1 und in der Gruppe der Patienten mit koronarer Herzkrankheit und ventrikulären Tachykardien 49,5±17,9. Bei einem Schwellenwert von 36 ergab sich eine Sensitivität von 80%, eine Spezifität von 93%, ein positiv prädiktiver Wert von 66% und ein negativ prädiktiver Wert von 96% bezüglich des Auftretens einer anhaltenden ventrikulären Tachykardie. Der Fragmentations-Index war korreliert mit dem Ausmaß der regionalen Wandbewegungsstörungen und der globalen linksventrikulären Ejektionsfraktion.Bei der Spätpotentialanalyse ergaben sich überraschend niedrige Werte für Sensitivität (20%) und positiv prädiktiven Wert (50%) bei einer Spezifität von 96% und einem negativ prädiktiven Wert von 88%. Bei der Errechnung des FI aus den elektrischen Signalen konnten die drei Gruppen nur unzureichend unterschieden werden.In der 2-jährigen Nachverfolgungsperiode der Postinfarkt-Patienten erlitt ein Patient Kammerflimmern und konnte erfolgreich reanimiert werden. Der FI dieses Patienten betrug 17.Ein Patient mit koronarer 3-Gefäß-Erkrankung verstarb an einem akuten Myokardinfarkt. Sein FI betrug 39.Schlußfolgerung: Mittels der Magnetokardiographie konnte eine fragmentierte ventrikuläre Aktivierung bei Patienten mit koronarer Herzkrankheit auch im QRS-Komplex nachgewiesen werden und zu abgelaufenen ventrikulären Tachykardien korreliert werden.SummaryFragmented 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 (p<0,005). 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.Conclusion: 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.

Magnetkardiographischer Nachweis abnormer intraventrikulärer Erregungsausbreitung bei ischämie-bedingter Herzerkrankung ohne und mit Tachykardien@@@Magnetcardiographic detection of abnormal intraventricular activation in patients with ischemic heart disease with and without tachycardia

UNLABELLED 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 (p<0,005). 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. CONCLUSION 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.ZusammenfassungFragmentierte und verzögerte Aktivierung des ventrikulären Myokards kann die Ursache für maligne tachykarde Herzrhythmusstörungen sein. Durch den Nachweis ventrikulärer Spätpotentiale wird nur eine sehr stark verzögerte Depolarisation, nicht aber die Intra-QRS-Aktivierung erfaßt. Ziel dieser Untersuchung war es daher, die gesamte Phase der ventrikulären Depolarisation zu untersuchen, eine abnorme elektrische Aktivierung magnetokardiographisch zu erfassen und zu quantifizieren sowie an einem kleinen Kollektiv koronarkranker Patienten die prognostische Bedeutung abzuschätzen.Bei 26 Gesunden, 32 Patienten nach akutem Myokardinfarkt ohne maligne ventrikuläre Arrhythmien und 10 Patienten mit koronarer Herzkrankheit und anhaltender, monomorpher ventrikulärer Tachykardie in der Anamnese wurde in einem magnetisch abgeschirmten Raum eine Magnetokardiographie mittels Superconducting Quantum Interference Device (SQUID)-Elementen durchgeführt. Zur Quantifizierung der fragmentierten Aktivierung im QRS wurde ein Fragmentations-Index (FI) berechnet. Bei jedem Patienten bzw. Gesunden wurde außerdem ein hochverstärktes EKG zur Analyse von Spätpotentialen, bei den Patienten mit koronarer Herzkrankheit eine Herzkatheteruntersuchung und bei den Patienten mit ventrikulären Herzrhythmusstörungen eine elektrophysiologische Untersuchung durchgeführt.Es ergaben sich für die drei Gruppen hochsignifikant unterschiedliche Werte für den FI (p<0,005). Der mittlere FI in der Gruppe der Gesunden betrug 20,4±5,4, in der Gruppe der Postinfarkt-Patienten ohne Arrhythmien 27,2±12,1 und in der Gruppe der Patienten mit koronarer Herzkrankheit und ventrikulären Tachykardien 49,5±17,9. Bei einem Schwellenwert von 36 ergab sich eine Sensitivität von 80%, eine Spezifität von 93%, ein positiv prädiktiver Wert von 66% und ein negativ prädiktiver Wert von 96% bezüglich des Auftretens einer anhaltenden ventrikulären Tachykardie. Der Fragmentations-Index war korreliert mit dem Ausmaß der regionalen Wandbewegungsstörungen und der globalen linksventrikulären Ejektionsfraktion.Bei der Spätpotentialanalyse ergaben sich überraschend niedrige Werte für Sensitivität (20%) und positiv prädiktiven Wert (50%) bei einer Spezifität von 96% und einem negativ prädiktiven Wert von 88%. Bei der Errechnung des FI aus den elektrischen Signalen konnten die drei Gruppen nur unzureichend unterschieden werden.In der 2-jährigen Nachverfolgungsperiode der Postinfarkt-Patienten erlitt ein Patient Kammerflimmern und konnte erfolgreich reanimiert werden. Der FI dieses Patienten betrug 17.Ein Patient mit koronarer 3-Gefäß-Erkrankung verstarb an einem akuten Myokardinfarkt. Sein FI betrug 39.Schlußfolgerung: Mittels der Magnetokardiographie konnte eine fragmentierte ventrikuläre Aktivierung bei Patienten mit koronarer Herzkrankheit auch im QRS-Komplex nachgewiesen werden und zu abgelaufenen ventrikulären Tachykardien korreliert werden.SummaryFragmented 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 (p<0,005). 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.Conclusion: 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.