Arvydas Matiukas

Lithuanian University of Health Sciences, Kaunas, Kauno Apskritis, Lithuania

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Publications (15)31.62 Total impact

  • Heart Rhythm. 11/2014; 11(11):2136.
  • Arvydas Matiukas, Arkady M. Pertsov
    Biophysical Journal 01/2013; 104(2):670-. · 3.67 Impact Factor
  • Biophysical Journal 01/2013; 104(2):337-. · 3.67 Impact Factor
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    ABSTRACT: Voltage-sensitive fluorescent dyes have become a major tool in cardiac and neuro-electrophysiology. Achieving high signal-to-noise ratios requires increased illumination intensities, which may cause photobleaching and phototoxicity. The optimal range of illumination intensities varies for different dyes and must be evaluated individually. We evaluate two dyes: di-4-ANBDQBS (excitation 660 nm) and di-4-ANEPPS (excitation 532 nm) in the guinea pig heart. The light intensity varies from 0.1 to 5  mW/mm2, with the upper limit at 5 to 10 times above values reported in the literature. The duration of illumination was 60 s, which in guinea pigs corresponds to 300 beats at a normal heart rate. Within the identified duration and intensity range, neither dye shows significant photobleaching or detectable phototoxic effects. However, light absorption at higher intensities causes noticeable tissue heating, which affects the electrophysiological parameters. The most pronounced effect is a shortening of the action potential duration, which, in the case of 532-nm excitation, can reach ∼30%. At 660-nm excitation, the effect is ∼10%. These findings may have important implications for the design of optical mapping protocols in biomedical applications.
    Journal of Biomedical Optics 09/2012; 17(9):96007-1. · 2.75 Impact Factor
  • Biophysical Journal 01/2011; 100(3). · 3.67 Impact Factor
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    ABSTRACT: Real-time optical registration of electrical activity in the heart allows the study of arrhythmogenic mechanisms, in particular due to global ischemia. It is known that global ischemia increases electrical heterogeneity in the heart. However, inter-ventricular differences between the right (RV) and left ventricle (LV) during ischemia and their relationship to arrhythmogenesis remains poorly understood. We used high resolution optical mapping (di-4-ANEPPS, excitation at 532 nm, emission at 640+/-50 nm) of Langendorff-perfused rabbit hearts to quantify inter-ventricular heterogeneity in the heart during periodic pacing and ventricular fibrillation. Two fast CCD cameras were used to record electrical activity from the RV and LV during control, global ischemia (20 min), and reperfusion. Hearts were paced at progressively reduced (from 300 ms to 100 ms) basic cycle lengths and ventricular fibrillation was induced by burst pacing and recorded before the global ischemia, and after the reperfusion. The action potential durations (APD), maximum slopes of APD restitution curves (S(max)), and mean dominant frequency (DF) of ventricular fibrillation were measured for both LV and RV surfaces. No APD heterogeneity was observed in control hearts. Global ischemia induced inter-ventricular heterogeneity in APDs (RV: 109+/-21 ms, LV: 89+/-23 ms; p<0.01) that was abolished upon reperfusion. However, S(max) was uniformly decreased in both RV (control: 0.94+/-0.25, ischemia: 0.36+/-0.12; p<0.01) and LV (control: 0.99+/-0.24, ischemia: 0.43+/-0.21; p<0.01) and did not recover upon reperfusion. In addition, the DF of ventricular fibrillation during reperfusion decreased significantly in RV (from 8.6+/-1.3 Hz to 6.2+/-1.1 Hz; p<0.05) but remained the same in LV (9.0+/-0.8 Hz vs 8.5+/-1.0 Hz). Thus, our results demonstrate that global ischemia induces inter-ventricular heterogeneity in APD during periodic pacing. Although this effect was abolished upon reperfusion, S(max) did not recover, indicating the presence of residual changes in electrical properties of the heart. Therefore, reperfusion reveals the presence of inter-ventricular heterogeneities in the dynamics of ventricular fibrillation.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2009; 2009:6321-4.
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    ABSTRACT: The development of voltage-sensitive dyes has revolutionized cardiac electrophysiology and made optical imaging of cardiac electrical activity possible. Photon diffusion models coupled to electrical excitation models have been successful in qualitatively predicting the shape of the optical action potential and its dependence on subsurface electrical wave orientation. However, the accuracy of the diffusion equation in the visible range, especially for thin tissue preparations, remains unclear. Here, we compare diffusion and Monte Carlo (MC) based models and we investigate the role of tissue thickness. All computational results are compared to experimental data obtained from intact guinea pig hearts. We show that the subsurface volume contributing to the epi-fluorescence signal extends deeper in the tissue when using MC models, resulting in longer optical upstroke durations which are in better agreement with experiments. The optical upstroke morphology, however, strongly correlates to the subsurface propagation direction independent of the model and is consistent with our experimental observations.
    Optics Express 10/2008; 16(18):13758-72. · 3.55 Impact Factor
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    ABSTRACT: Mapping the myocardial fiber organization is important for assessing the electrical and mechanical properties of normal and diseased hearts. Current methods to determine the fiber organization have several limitations: histological sectioning mechanically distorts the tissue and is labor-intensive, while diffusion tensor imaging has low spatial resolution and requires expensive MRI scanners. Here, we utilized optical clearing, a fluorescent dye, and confocal microscopy to create three-dimensional reconstructions of the myocardial fiber organization of guinea pig and mouse hearts. We have optimized the staining and clearing procedure to allow for the nondestructive imaging of whole hearts with a thickness up to 3.5 mm. Myocardial fibers could clearly be identified at all depths in all preparations. We determined the change of fiber orientation across strips of guinea pig left ventricular wall. Our study confirms the qualitative result that there is a steady counterclockwise fiber rotation across the ventricular wall. Quantitatively, we found a total fiber rotation of 105.7+/-14.9 degrees (mean+/-standard error of the mean); this value lies within the range reported by previous studies. These results show that optical clearing, in combination with a fluorescent dye and confocal microscopy, is a practical and accurate method for determining myocardial fiber organization.
    Microscopy Research and Technique 08/2008; 71(7):510-6. · 1.59 Impact Factor
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    ABSTRACT: Information about intramural propagation of electrical excitation is crucial to understanding arrhythmia mechanisms in thick ventricular muscle. There is currently a controversy over whether it is possible to extract such information from the shape of the upstroke in optical mapping recordings. We show that even in the complex geometry of a whole guinea pig heart, optical upstroke morphology reveals the 3D wavefront orientation near the surface. To characterize the upstroke morphology, we use V(F)(*), the fractional level at which voltage-sensitive fluorescence, V(F), has maximal time derivative. Low values of V(F)(*)( approximately 0.2) indicate a wavefront moving away from the surface, high values of V(F)(*) ( approximately 0.6) a wavefront moving toward the surface, and intermediate values of V(F)(*) ( approximately 0.4) a wavefront moving parallel to the surface. We further performed computer simulations using Luo-Rudy II electrophysiology and a simplified 3D geometry. The simulated V(F)(*) maps for free wall and apical stimulations as well as for sinus rhythm are in good quantitative agreement with the averaged experimental results. Furthermore, computer simulations show that the effect of the curvature of the heart on wave propagation is negligible.
    Biophysical Journal 08/2008; 95(2):942-50. · 3.67 Impact Factor
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    ABSTRACT: The subsurface electrical wave orientation in cardiac tissue is inferred from epi-fluorescence measurements. It is calculated using coupled electrophysiological and photon transport models. We compare Monte Carlo and diffusion based models, showing only minor differences.
    Biomedical Optics; 03/2008
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    ABSTRACT: We report a fast laser-scanning system for imaging rapidly propagating electrical waves inside the ventricular wall with 1 ms time resolution. The system uses a novel biaxial scanning algorithm and near-infrared voltage-sensitive dyes.
    Biomedical Optics; 03/2008
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    ABSTRACT: Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been used successfully for optical mapping in cardiac cells and tissues. However, their utility for probing electrical activity deep inside the myocardial wall and in blood-perfused myocardium has been limited because of light scattering and high absorption by endogenous chromophores and hemoglobin at blue-green excitation wavelengths. The purpose of this study was to characterize two new styryl dyes--di-4-ANBDQPQ (JPW-6003) and di-4-ANBDQBS (JPW-6033)--optimized for blood-perfused tissue and intramural optical mapping. Voltage-dependent spectra were recorded in a model lipid bilayer. Optical mapping experiments were conducted in four species (mouse, rat, guinea pig, and pig). Hearts were Langendorff perfused using Tyrode's solution and blood (pig). Dyes were loaded via bolus injection into perfusate. Transillumination experiments were conducted in isolated coronary-perfused pig right ventricular wall preparations. The optimal excitation wavelength in cardiac tissues (650 nm) was >70 nm beyond the absorption maximum of hemoglobin. Voltage sensitivity of both dyes was approximately 10% to 20%. Signal decay half-life due to dye internalization was 80 to 210 minutes, which is 5 to 7 times slower than for di-4-ANEPPS. In transillumination mode, DeltaF/F was as high as 20%. In blood-perfused tissues, DeltaF/F reached 5.5% (1.8 times higher than for di-4-ANEPPS). We have synthesized and characterized two new near-infrared dyes with excitation/emission wavelengths shifted >100 nm to the red. They provide both high voltage sensitivity and 5 to 7 times slower internalization rate compared to conventional dyes. The dyes are optimized for deeper tissue probing and optical mapping of blood-perfused tissue, but they also can be used for conventional applications.
    Heart Rhythm 11/2007; 4(11):1441-51. · 5.05 Impact Factor
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    ABSTRACT: Styryl voltage-sensitive dyes (e.g., di-4-ANEPPS) have been widely and successfully used as probes for mapping membrane potential changes in cardiac cells and tissues. However, their utility has been somewhat limited because their excitation wavelengths have been restricted to the 450- to 550-nm range. Longer excitation/emission wavelength probes can minimize interference from endogenous chromophores and, because of decreased light scattering and lower absorption by endogenous chromophores, improve recording from deeper tissue layers. In this article, we report efforts to develop new potentiometric styryl dyes that have excitation wavelengths ranging above 700 nm and emission spectra extending to 900 nm. Three dyes for cardiac optical mapping were investigated in depth from several hundred dyes containing 47 variants of the styryl chromophores. Absorbance and emission spectra in ethanol and multilamellar vesicles, as well as voltage-dependent spectral changes in a model lipid bilayer, have been recorded for these dyes. Optical action potentials were recorded in typical cardiac tissues (rat, guinea pig, pig) and compared with those of di-4-ANEPPS. The voltage sensitivities of the fluorescence of these new potentiometric indicators are as good as those of the widely used ANEP series of probes. In addition, because of molecular engineering of the chromophore, the new dyes provide a wide range of dye loading and washout time constants. These dyes will enable a series of new experiments requiring the optical probing of thick and/or blood-perfused cardiac tissues.
    AJP Heart and Circulatory Physiology 07/2006; 290(6):H2633-43. · 4.01 Impact Factor
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    ABSTRACT: The rotating fiber orientation within the cardiac wall substantially affects the electrical propagation and can cause intra-myocardial cusp waves. Numerical simulations have shown that the cusps form in layers where propagation is perpendicular to the fiber orientation and lead to complex wave front morphologies. They can travel across layers and break through at the epi- or endocardial surfaces where they cause apparent accelerations of propagation. The validation of these results remains a major experimental challenge. In the present study, we investigate both computationally and experimentally how intramural cusp waves can be detected using optical imaging. Our simulations show that cusps alter the optical upstroke morphology and can be detected well before they reach the surface (up to 1 mm deep). Experiments in Langendorff-perfused guinea pig hearts are consistent with our numerical findings.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 02/2006; 1:1564-7.
  • Article: AB37-5
    Heart Rhythm. 01/2006; 3(5).

Publication Stats

80 Citations
31.62 Total Impact Points

Institutions

  • 2012
    • Lithuanian University of Health Sciences
      • Institute of Cardiology
      Kaunas, Kauno Apskritis, Lithuania
  • 2006–2009
    • State University of New York Upstate Medical University
      • Department of Pharmacology
      Syracuse, NY, United States
    • Ghent University
      • Department of Physics and Astronomy
      Gent, VLG, Belgium
  • 2008
    • Kaunas University of Technology
      Caunas, Kauno Apskritis, Lithuania