Publications by authors named "Peter Kneppo"

3 Publications

  • Page 1 of 1

Multi-lead vs single-lead T -T interval measurements for prediction of reperfusion ventricular tachyarrhythmias.

J Cardiovasc Electrophysiol 2019 10 21;30(10):2090-2097. Epub 2019 Aug 21.

Department of Cardiac Physiology, Institute of Physiology, Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar, Russia.

Introduction: Electrocardiographic T -T interval (Tp-Te) is a promising marker for the prediction of ventricular tachycardia and/or ventricular fibrillation (VT/VF). The study was aimed to compare single-lead vs multilead Tp-Te variables as VT/VF predictors in experimental ischemia/reperfusion model.

Methods And Results: Computer simulations were done using the ECGSIM model with an ischemic region set in anterior left ventricular apex. In 18 anesthetized cats, myocardial ischemia was induced by 30-minute ligation of left anterior descending coronary artery followed by reperfusion. Body surface ECGs in limb leads and modified precordial leads were recorded. Tp-Te was detected automatically in individual leads with a custom-designed parametric algorithm. Tp-Te dispersion and total Tp-Te were calculated as a difference between the maximal and minimal value of individual Tp-Te(s) and an interval between the earliest Tpeak and the latest Tend throughout all leads, respectively. Simulations showed that the increase of local, but not total, dispersion of repolarization characteristic for ischemic damage led to nonuniform shortening of T-peak times across 12 standard leads, which in turn resulted in the increase of single-lead Tp-Te(s), total Tp-Te and Tp-Te dispersion. Animals experienced VT/VF showed increased Tp-Te dispersion and total Tp-Te during reperfusion. In univariate logistic regression analysis, only the Tp-Te dispersion at the beginning of reperfusion was associated with the VT/VF incidence. According to ROC curve analysis, the optimal cut-off value of the Tp-Te dispersion was 17 ms (sensitivity 0.71, specificity 0.80).

Conclusions: The reperfusion VT/VFs were independently predicted by increased Tp-Te dispersion, which suggests the importance of multi-lead evaluation of Tp-Te intervals.
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October 2019

Electrocardiographic diagnosis of left ventricular hypertrophy on the basis of dipole electrocardiotopography method.

J Electrocardiol 2008 Nov-Dec;41(6):697.e1-6

Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia.

Purpose: The aim of this study was to verify a new criterion of hypertension-related left ventricular hypertrophy (LVH) on the basis of the dipole electrocardiotopographic technique, which provides intelligible pictorial patterns and efficient quantitative parameters for recognition of pathologic states of the heart.

Methods: Standard 12-lead and vectorcardiographic measurements with the McFee-Parungao lead system were carried out for 289 echocardiographically accessed healthy subjects and hypertensive patients with LVH. The proposed parameter index of left ventricular hypertrophy for recognition of LVH is a product of the following 3 characteristics: maximum magnitude of depolarization vector, total duration of ventricular depolarization, and local spatial integral of activation duration. This parameter was compared with several other parameters commonly used for LVH diagnosis. The diagnostic efficiencies of these parameters were statistically estimated and compared using the receiver operating characteristics (ROC curves), area under the ROC curve, and partial areas under the ROC curve (pAUC). The area under the ROC curve values were compared by the standard nonparametric method, and pAUC comparison was performed by bootstrap methodology.

Results: The ROC curves display the definite advantage of the proposed criterion, especially for the specificities greater than 0.7. Statistical comparative analysis showed that the corresponding pAUC for the index of left ventricular hypertrophy is greater than for R(x) + S(z), Cornell product, and Sokolow-Lyon criteria at confidence level > or = .95.

Conclusion: The dipole electrocardiotopography-based diagnostic criterion of LVH is demonstrated to be statistically more accurate as compared to other criteria studied. The advantage of this criterion suggests that with the use of decartograms, it is possible to reveal some additional information not accessible for other diagnostic tools. Decartograms help to visualize and quantify the redistribution of activation duration over the myocardium, thus providing a valuable instrument for heuristic analysis and dynamic observation of the heart state affected by LVH.
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January 2009

Modular measuring system for assessment of the thyroid gland functional state.

Conf Proc IEEE Eng Med Biol Soc 2005;2005:6646-9

Institute for Biomedical Engineering, Czech Technical University in Prague, Czech Republic.

Distributed modular system BioLab for biophysical examinations enabling assessment of the thyroid gland functional state is presented. Two smart sensors modules measuring 4 different biosignals are connected to an Ethernet based network and enable to obtain peripheral indicators of human cardiovascular and neuromuscular functions. Personal notebook or desktop computer with a network interface controls the sensors and performs processing and evaluation of measured biosignals.
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September 2008