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Evaluation of excitation propagation in the rabbit heart: optical mapping and transmural microelectrode recordings.

Mačianskienė R, Martišienė I, Navalinskas A, Vosyliūtė R, Treinys R, Vaidelytė B, Benetis R, Jurevičius J - PLoS ONE (2015)

Bottom Line: Because of the optical features of heart tissue, optical and electrical action potentials are only moderately associated, especially when near-infrared dyes are used in optical mapping (OM) studies.These components correspond to the components of the propagating electrical wave that are transmural and parallel to the epicardium.The co-registration of OM and transmural microelectrode APs enabled the probing depth of fluorescence measurements to be calculated and the OAP upstroke to be divided into two components (depth-weighted and lateral-scattering), and it also allowed the relative strengths of their effects on the shape of the OAP upstroke to be evaluated.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania.

ABSTRACT

Background: Because of the optical features of heart tissue, optical and electrical action potentials are only moderately associated, especially when near-infrared dyes are used in optical mapping (OM) studies.

Objective: By simultaneously recording transmural electrical action potentials (APs) and optical action potentials (OAPs), we aimed to evaluate the contributions of both electrical and optical influences to the shape of the OAP upstroke.

Methods and results: A standard glass microelectrode and OM, using an near-infrared fluorescent dye (di-4-ANBDQBS), were used to simultaneously record transmural APs and OAPs in a Langendorff-perfused rabbit heart during atrial, endocardial, and epicardial pacing. The actual profile of the transmural AP upstroke across the LV wall, together with the OAP upstroke, allowed for calculations of the probing-depth constant (k ~2.1 mm, n = 24) of the fluorescence measurements. In addition, the transmural AP recordings aided the quantitative evaluation of the influences of depth-weighted and lateral-scattering components on the OAP upstroke. These components correspond to the components of the propagating electrical wave that are transmural and parallel to the epicardium. The calculated mean values for the depth-weighted and lateral-scattering components, whose sum comprises the OAP upstroke, were (in ms) 10.18 ± 0.62 and 0.0 ± 0.56 for atrial stimulation, 9.37 ± 1.12 and 3.01 ± 1.30 for endocardial stimulation, and 6.09 ± 0.79 and 8.16 ± 0.98 for epicardial stimulation; (n = 8 for each). For this dye, 90% of the collected fluorescence originated up to 4.83 ± 0.18 mm (n = 24) from the epicardium.

Conclusions: The co-registration of OM and transmural microelectrode APs enabled the probing depth of fluorescence measurements to be calculated and the OAP upstroke to be divided into two components (depth-weighted and lateral-scattering), and it also allowed the relative strengths of their effects on the shape of the OAP upstroke to be evaluated.

No MeSH data available.


Related in: MedlinePlus

Characterization of optical and electrical APs using various stimulations of a whole rabbit heart.(A-C) Examples of simultaneous recordings of an OAP (light gray) and two APs, epicardial (gray) and subendocardial (black). The start time of the OAP was synchronized with that of the electrical APs. (D-F) Superimposition of the upstrokes of the subendo-/epi-AP and OAP from A-C on an expanded time scale. The cross indicates the crossing point between the OAP and the APs obtained from subendo- and epicardium. (G-I) OAP activation-time maps for atrial/endocardial/epicardial pacing. The interval between the isochrones (black lines) is 2 ms. Numbers near isochrones show the activation time in ms. The asterisks and the square pulse indicate the location of the microelectrodes and the stimulating electrode, respectively, on the epicardial surface. Stimulation period: 300 ms.
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pone.0123050.g002: Characterization of optical and electrical APs using various stimulations of a whole rabbit heart.(A-C) Examples of simultaneous recordings of an OAP (light gray) and two APs, epicardial (gray) and subendocardial (black). The start time of the OAP was synchronized with that of the electrical APs. (D-F) Superimposition of the upstrokes of the subendo-/epi-AP and OAP from A-C on an expanded time scale. The cross indicates the crossing point between the OAP and the APs obtained from subendo- and epicardium. (G-I) OAP activation-time maps for atrial/endocardial/epicardial pacing. The interval between the isochrones (black lines) is 2 ms. Numbers near isochrones show the activation time in ms. The asterisks and the square pulse indicate the location of the microelectrodes and the stimulating electrode, respectively, on the epicardial surface. Stimulation period: 300 ms.

Mentions: Fig 2A–2C shows OAP (upper) and electrical APs recordings (lower) and their superimposed upstrokes on an expanded time scale (Fig 2D–2F) for stimulations of the atrium (left), endocardium (middle), and epicardium (right). The upstroke duration of the subendo-AP was marginally shorter (in ms: 1.07 ± 0.25, 1.61 ± 0.45 and 1.09 ± 0.22) than that of the epi-AP (2.17 ± 0.27 ms, 2.64 ± 0.23 ms and 2.44 ± 0.28 ms; n = 8 for each; P <0.05) when stimulated from the atrium, endocardium and epicardium, respectively. However, the OAP upstroke duration under the same experimental conditions was much longer (10.15 ± 0.29 ms, 12.38 ± 0.51 ms, and 14.26 ± 0.58 ms, respectively; n = 8; P <0.05). The difference in AP upstroke duration occurred because the OAP, which was measured using the di-4-ANBDQBS dye, was the result of the summation of propagating electrical signals obtained from multiple cells in the LV wall [8,16], while the AP was obtained from a single cell. The mean values of standard AP parameters are presented in S1 Table.


Evaluation of excitation propagation in the rabbit heart: optical mapping and transmural microelectrode recordings.

Mačianskienė R, Martišienė I, Navalinskas A, Vosyliūtė R, Treinys R, Vaidelytė B, Benetis R, Jurevičius J - PLoS ONE (2015)

Characterization of optical and electrical APs using various stimulations of a whole rabbit heart.(A-C) Examples of simultaneous recordings of an OAP (light gray) and two APs, epicardial (gray) and subendocardial (black). The start time of the OAP was synchronized with that of the electrical APs. (D-F) Superimposition of the upstrokes of the subendo-/epi-AP and OAP from A-C on an expanded time scale. The cross indicates the crossing point between the OAP and the APs obtained from subendo- and epicardium. (G-I) OAP activation-time maps for atrial/endocardial/epicardial pacing. The interval between the isochrones (black lines) is 2 ms. Numbers near isochrones show the activation time in ms. The asterisks and the square pulse indicate the location of the microelectrodes and the stimulating electrode, respectively, on the epicardial surface. Stimulation period: 300 ms.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400155&req=5

pone.0123050.g002: Characterization of optical and electrical APs using various stimulations of a whole rabbit heart.(A-C) Examples of simultaneous recordings of an OAP (light gray) and two APs, epicardial (gray) and subendocardial (black). The start time of the OAP was synchronized with that of the electrical APs. (D-F) Superimposition of the upstrokes of the subendo-/epi-AP and OAP from A-C on an expanded time scale. The cross indicates the crossing point between the OAP and the APs obtained from subendo- and epicardium. (G-I) OAP activation-time maps for atrial/endocardial/epicardial pacing. The interval between the isochrones (black lines) is 2 ms. Numbers near isochrones show the activation time in ms. The asterisks and the square pulse indicate the location of the microelectrodes and the stimulating electrode, respectively, on the epicardial surface. Stimulation period: 300 ms.
Mentions: Fig 2A–2C shows OAP (upper) and electrical APs recordings (lower) and their superimposed upstrokes on an expanded time scale (Fig 2D–2F) for stimulations of the atrium (left), endocardium (middle), and epicardium (right). The upstroke duration of the subendo-AP was marginally shorter (in ms: 1.07 ± 0.25, 1.61 ± 0.45 and 1.09 ± 0.22) than that of the epi-AP (2.17 ± 0.27 ms, 2.64 ± 0.23 ms and 2.44 ± 0.28 ms; n = 8 for each; P <0.05) when stimulated from the atrium, endocardium and epicardium, respectively. However, the OAP upstroke duration under the same experimental conditions was much longer (10.15 ± 0.29 ms, 12.38 ± 0.51 ms, and 14.26 ± 0.58 ms, respectively; n = 8; P <0.05). The difference in AP upstroke duration occurred because the OAP, which was measured using the di-4-ANBDQBS dye, was the result of the summation of propagating electrical signals obtained from multiple cells in the LV wall [8,16], while the AP was obtained from a single cell. The mean values of standard AP parameters are presented in S1 Table.

Bottom Line: Because of the optical features of heart tissue, optical and electrical action potentials are only moderately associated, especially when near-infrared dyes are used in optical mapping (OM) studies.These components correspond to the components of the propagating electrical wave that are transmural and parallel to the epicardium.The co-registration of OM and transmural microelectrode APs enabled the probing depth of fluorescence measurements to be calculated and the OAP upstroke to be divided into two components (depth-weighted and lateral-scattering), and it also allowed the relative strengths of their effects on the shape of the OAP upstroke to be evaluated.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania.

ABSTRACT

Background: Because of the optical features of heart tissue, optical and electrical action potentials are only moderately associated, especially when near-infrared dyes are used in optical mapping (OM) studies.

Objective: By simultaneously recording transmural electrical action potentials (APs) and optical action potentials (OAPs), we aimed to evaluate the contributions of both electrical and optical influences to the shape of the OAP upstroke.

Methods and results: A standard glass microelectrode and OM, using an near-infrared fluorescent dye (di-4-ANBDQBS), were used to simultaneously record transmural APs and OAPs in a Langendorff-perfused rabbit heart during atrial, endocardial, and epicardial pacing. The actual profile of the transmural AP upstroke across the LV wall, together with the OAP upstroke, allowed for calculations of the probing-depth constant (k ~2.1 mm, n = 24) of the fluorescence measurements. In addition, the transmural AP recordings aided the quantitative evaluation of the influences of depth-weighted and lateral-scattering components on the OAP upstroke. These components correspond to the components of the propagating electrical wave that are transmural and parallel to the epicardium. The calculated mean values for the depth-weighted and lateral-scattering components, whose sum comprises the OAP upstroke, were (in ms) 10.18 ± 0.62 and 0.0 ± 0.56 for atrial stimulation, 9.37 ± 1.12 and 3.01 ± 1.30 for endocardial stimulation, and 6.09 ± 0.79 and 8.16 ± 0.98 for epicardial stimulation; (n = 8 for each). For this dye, 90% of the collected fluorescence originated up to 4.83 ± 0.18 mm (n = 24) from the epicardium.

Conclusions: The co-registration of OM and transmural microelectrode APs enabled the probing depth of fluorescence measurements to be calculated and the OAP upstroke to be divided into two components (depth-weighted and lateral-scattering), and it also allowed the relative strengths of their effects on the shape of the OAP upstroke to be evaluated.

No MeSH data available.


Related in: MedlinePlus