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A. P. Fischer - One of the best experts on this subject based on the ideXlab platform.
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Surgical treatment of Tachyarrhythmias.
Journal of Cardiovascular Pharmacology, 1991Co-Authors: A. P. FischerAbstract:Tachyarrhythmia surgery should be divided into two separate groups: supraventricular and ventricular. Supraventricular Tachyarrhythmias (SVT): The first surgical cure of the Wolff-Parkinson-White syndrome (WPW) in 1968 led to a better understanding of the pathophysiology and anatomy of this syndrome. WPW should now be classified by its anatomical location as defined by the preoperative and intraoperative mapping. At present, there are two surgical approaches for WPW, endocardial or epicardial
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Surgical treatment of Tachyarrhythmias.
Journal of cardiovascular pharmacology, 1991Co-Authors: A. P. FischerAbstract:Tachyarrhythmia surgery should be divided into two separate groups: supraventricular and ventricular. Supraventricular Tachyarrhythmias (SVT): The first surgical cure of the Wolff-Parkinson-White syndrome (WPW) in 1968 led to a better understanding of the pathophysiology and anatomy of this syndrome. WPW should now be classified by its anatomical location as defined by the preoperative and intraoperative mapping. At present, there are two surgical approaches for WPW, endocardial or epicardial. Improvement of the surgical results has broadened the indications for surgery of WPW, making it the most commonly performed operation for SVT. Surgical treatment is briefly discussed for AV nodal reentrant tachycardia, ectopic (focal) atrial tachycardia, atrial flutter, and atrial fibrillation. Ventricular Tachyarrhythmias (VT): Different types of direct operations have been applied to the treatment of VT in ischemic heart disease. Because of the fairly high mortality and recurrence rate of these major operations in patients with poor ventricular function, there is now a marked increase in the use of implantable cardioverter-defibrillators as an indirect surgical approach.
Stefan H Hohnloser - One of the best experts on this subject based on the ideXlab platform.
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Ventricular Tachyarrhythmias and implantable cardioverter–defibrillator
Oxford Medicine Online, 2015Co-Authors: Joachim R Ehrlich, Stefan H HohnloserAbstract:Few scenarios in intensive coronary care are commonly associated with as much fear and apprehension as the event of a ventricular Tachyarrhythmia. This chapter provides information to help successfully manage such situations. Residents, fellows, and physicians involved in providing acute cardiac care are in need of broad background knowledge regarding the diagnostic and therapeutic means, as well as the prognostic implications of such events, in order to provide adequate medical care to their patients. The present chapter summarizes information on the pathophysiological basis of ventricular Tachyarrhythmias and teaches tools to detect and correctly differentiate a ventricular from a supraventricular arrhythmia on the surface electrocardiogram. The chapter provides the reader with a summary of specific treatment modalities and information on indications for treatment with an implantable cardioverter-defibrillator. Last, the chapter deals with the management of device interventions (appropriately delivered for ventricular Tachyarrhythmias or inappropriately delivered for other reasons) within the increasing population of patients fitted with an implantable cardioverter-defibrillator.
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quantitative assessment of microvolt t wave alternans in patients with congestive heart failure
Journal of Cardiovascular Electrophysiology, 2005Co-Authors: Thomas Klingenheben, Pawel Ptaszynski, Stefan H HohnloserAbstract:INTRODUCTION: T-wave alternans has been shown to be linked to the genesis of ventricular Tachyarrhythmias. Currently, only qualitative assessment of microvolt T-wave alternans (MTWA) is recommended in clinical practise. Whether quantitative assessment of MTWA yields complementary information is unknown. METHODS AND RESULTS: Noninvasive MTWA determination was performed in 204 consecutive patients with ischemic or nonischemic cardiomyopathy. Of those, 100 tested MTWA positive. In these recordings, MTWA magnitude was quantitatively assessed (alternans voltage, V(alt)). Patients were followed for a mean of 17 months. Ventricular tachyarrhythmic events constituted the study endpoint. Patients with nonischemic cardiomyopathy had a higher V(alt) than patients with ischemic cardiomyopathy (10.3 +/- 9.2 [median 7.2] vs 6.2 +/- 3.2 [median 4.6] microV; P = 0.007). The number of MTWA-positive ECG leads was also higher in patients nonischemic cardiomyopathy (7.3 +/- 2.4 [median 8] vs 6.0 +/- 2.5 [median 6]; P = 0.016). Patients who suffered an arrhythmic event during follow-up had higher MTWA voltages (10.8 +/- 10.0 [median 8.8] vs 7.4 +/- 5.7 [median 6.4] microV; P = 0.05) a higher number of MTWA-positive ECG leads (7.6 +/- 2.4 [median 8] vs 6.4 +/- 2.5 [median 6]; P = 0.05) compared to patients with an uncomplicated course. CONCLUSION: Patients with nonischemic cardiomyopathy and patients with tachyarrhythmic complications have more extensive MTWA possibly reflecting more extensive myocardial damage and a higher arrhythmia propensity.
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usefulness of microvolt t wave alternans for prediction of ventricular tachyarrhythmic events in patients with dilated cardiomyopathy results from a prospective observational study
Journal of the American College of Cardiology, 2003Co-Authors: Stefan H Hohnloser, Thomas Klingenheben, Daniel M Bloomfield, Omar H Dabbous, Richard J CohenAbstract:OBJECTIVES: This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND: Patients with DCM are at increased risk of sudden death from ventricular Tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS: A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS: During an average follow-up of 14 +/- 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p < 0.035 and p < 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS: Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.
Mintu P Turakhia - One of the best experts on this subject based on the ideXlab platform.
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ability of microvolt t wave alternans to modify risk assessment of ventricular tachyarrhythmic events a meta analysis
American Heart Journal, 2012Co-Authors: Anurag Gupta, Donald D Hoang, Leah S Karliner, Jeffrey A Tice, Paul A Heidenreich, Paul J Wang, Mintu P TurakhiaAbstract:Background Prior studies have indicated that the magnitude of risk association of microvolt T-wave alternans (MTWA) testing appears to vary with the population studied. We performed a meta-analysis to determine the ability of MTWA to modify risk assessment of ventricular tachyarrhythmic events (VTEs) and sudden cardiac death (SCD) across a series of patient risk profiles using likelihood ratio (LR) testing, a measure of test performance independent of disease prevalence. Methods We identified original research articles published from January 1990 to January 2011 that investigate spectrally derived MTWA. Ventricular tachyarrhythmic event was defined as the total and arrhythmic mortality and nonfatal sustained or implantable cardioverter-defibrillator–treated ventricular Tachyarrhythmias. Summary estimates were created for positive and nonnegative MTWA results using a random-effects model and were expressed as positive (LR+) and negative (LR−) LRs. Results Of 1,534 articles, 20 prospective cohort studies met our inclusion criteria, consisting of 5,945 subjects predominantly with prior myocardial infarction or left ventricular dysfunction. Although there was a modest association between positive MTWA and VTE (relative risk 2.45, 1.58-3.79) and nonnegative MTWA and VTE (3.68, 2.23-6.07), test performance was poor (positive MTWA: LR+ 1.78, LR− 0.43; nonnegative MTWA: LR+ 1.38, LR− 0.56). Subgroup analyses of subjects classified as prior VTE, post–myocardial infarction, SCD-HeFT type, and MADIT-II type had a similar poor test performance. A negative MTWA result would decrease the annualized risk of VTE from 8.85% to 6.37% in MADIT-II–type patients and from 5.91% to 2.60% in SCD-HeFT–type patients. Conclusions Despite a modest association, results of spectrally derived MTWA testing do not sufficiently modify the risk of VTE to change clinical decisions.
Richard J Cohen - One of the best experts on this subject based on the ideXlab platform.
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usefulness of microvolt t wave alternans for prediction of ventricular tachyarrhythmic events in patients with dilated cardiomyopathy results from a prospective observational study
Journal of the American College of Cardiology, 2003Co-Authors: Stefan H Hohnloser, Thomas Klingenheben, Daniel M Bloomfield, Omar H Dabbous, Richard J CohenAbstract:OBJECTIVES: This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND: Patients with DCM are at increased risk of sudden death from ventricular Tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS: A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS: During an average follow-up of 14 +/- 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p < 0.035 and p < 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS: Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.
Thomas Klingenheben - One of the best experts on this subject based on the ideXlab platform.
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quantitative assessment of microvolt t wave alternans in patients with congestive heart failure
Journal of Cardiovascular Electrophysiology, 2005Co-Authors: Thomas Klingenheben, Pawel Ptaszynski, Stefan H HohnloserAbstract:INTRODUCTION: T-wave alternans has been shown to be linked to the genesis of ventricular Tachyarrhythmias. Currently, only qualitative assessment of microvolt T-wave alternans (MTWA) is recommended in clinical practise. Whether quantitative assessment of MTWA yields complementary information is unknown. METHODS AND RESULTS: Noninvasive MTWA determination was performed in 204 consecutive patients with ischemic or nonischemic cardiomyopathy. Of those, 100 tested MTWA positive. In these recordings, MTWA magnitude was quantitatively assessed (alternans voltage, V(alt)). Patients were followed for a mean of 17 months. Ventricular tachyarrhythmic events constituted the study endpoint. Patients with nonischemic cardiomyopathy had a higher V(alt) than patients with ischemic cardiomyopathy (10.3 +/- 9.2 [median 7.2] vs 6.2 +/- 3.2 [median 4.6] microV; P = 0.007). The number of MTWA-positive ECG leads was also higher in patients nonischemic cardiomyopathy (7.3 +/- 2.4 [median 8] vs 6.0 +/- 2.5 [median 6]; P = 0.016). Patients who suffered an arrhythmic event during follow-up had higher MTWA voltages (10.8 +/- 10.0 [median 8.8] vs 7.4 +/- 5.7 [median 6.4] microV; P = 0.05) a higher number of MTWA-positive ECG leads (7.6 +/- 2.4 [median 8] vs 6.4 +/- 2.5 [median 6]; P = 0.05) compared to patients with an uncomplicated course. CONCLUSION: Patients with nonischemic cardiomyopathy and patients with tachyarrhythmic complications have more extensive MTWA possibly reflecting more extensive myocardial damage and a higher arrhythmia propensity.
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usefulness of microvolt t wave alternans for prediction of ventricular tachyarrhythmic events in patients with dilated cardiomyopathy results from a prospective observational study
Journal of the American College of Cardiology, 2003Co-Authors: Stefan H Hohnloser, Thomas Klingenheben, Daniel M Bloomfield, Omar H Dabbous, Richard J CohenAbstract:OBJECTIVES: This study was designed to evaluate the ability of microvolt-level T-wave alternans (MTWA) to identify prospectively patients with idiopathic dilated cardiomyopathy (DCM) at risk of ventricular tachyarrhythmic events and to compare its predictive accuracy with that of conventional risk stratifiers. BACKGROUND: Patients with DCM are at increased risk of sudden death from ventricular Tachyarrhythmias. At present, there are no established methods of assessing this risk. METHODS: A total of 137 patients with DCM underwent risk stratification through assessment of MTWA, left ventricular ejection fraction, baroreflex sensitivity (BRS), heart rate variability, presence of nonsustained ventricular tachycardia (VT), signal-averaged electrocardiogram, and presence of intraventricular conduction defect. The study end point was either sudden death, resuscitated ventricular fibrillation, or documented hemodynamically unstable VT. RESULTS: During an average follow-up of 14 +/- 6 months, MTWA and BRS were significant univariate predictors of ventricular tachyarrhythmic events (p < 0.035 and p < 0.015, respectively). Multivariate Cox regression analysis revealed that only MTWA was a significant predictor. CONCLUSIONS: Microvolt-level T-wave alternans is a powerful independent predictor of ventricular tachyarrhythmic events in patients with DCM.