The role of approximate entropy in predicting ventricular defibrillation threshold

Ali Hamzei, Toshihiko Ohara, Young Hoon Kim, Moon Hyoung Lee, Olga Voroshilovski, Shien-Fong Lin, James N. Weiss, Peng-Sheng Chen, Hrayr S. Karagueuzian

Research output: Contribution to journalArticle

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Abstract

Background: The role of myocardial tissue mass on ventricular defibrillation threshold (DFT) is unclear. We hypothesized that changes in tissue mass modulate DFT by changing ventricular fibrillation (VF) wavefront regularity (entropy). Methods and Results: The right ventricles (RV) of seven farm pigs were isolated, superfused and perfused through the right coronary artery with oxygenated Tyrode's solution at 37°C. The epicardial surface was stained with the voltage sensitive dye, di-4-ANEPPS, and activation wavefront numbers (AWN) during VF were determined from the optical maps using a CCD camera (96 × 96 pixels over a 3.5 × 3.5 cm area). The RV mass was progressively reduced by sequential cutting of 1 to 2 g of tissue (approximately 12 cuts in total) distal to the perfusion site. After each cut, VF was reinduced, optical maps obtained, and the 50% probability of successful DFT50 determined using an up-down algorithm. After each cut, the approximate entropy (ApEn) was also computed using 5 seconds of VF data obtained with a bipolar electrode and a pseudo-electrocardiogram. Tissue mass reduction of up to one third of the RV mass (ie, from 48.4 ± 4.25 g to 34 ± 4.7 g) caused little or no change in the DFT, ApEn or AWN. However, further progressive reduction of the RV mass near the critical mass of VF resulted in a significant (P <0.05) progressive decrease in all three measured parameters. DFT energy was reduced by 27% (1.47 ± 0.34 J vs. 1.02 ± 0.14 J). There was a significant (P <0.01) correlation between the DFT and ApEn, which significantly further increased (P <0.001) near the critical mass. In a separate series of 6 isolated RVs, the ApEn correlated well with the Kolmogorov-Sinai (K-S) entropy, the standard method of calculating entropy. Conclusion: Tissue mass reduction significantly reduces DFT when the mass reduction increases VF wavefront regularity.

Original languageEnglish (US)
Pages (from-to)45-52
Number of pages8
JournalJournal of Cardiovascular Pharmacology and Therapeutics
Volume7
Issue number1
StatePublished - 2002
Externally publishedYes

Fingerprint

Entropy
Ventricular Fibrillation
Heart Ventricles
Third Ventricle
Coronary Vessels
Electrocardiography
Electrodes
Coloring Agents
Swine
Perfusion

Keywords

  • Approximate entropy
  • Defibrillation threshold
  • Electrical stimulation
  • Mapping
  • Ventricular fibrillation

ASJC Scopus subject areas

  • Pharmacology
  • Cardiology and Cardiovascular Medicine

Cite this

Hamzei, A., Ohara, T., Kim, Y. H., Lee, M. H., Voroshilovski, O., Lin, S-F., ... Karagueuzian, H. S. (2002). The role of approximate entropy in predicting ventricular defibrillation threshold. Journal of Cardiovascular Pharmacology and Therapeutics, 7(1), 45-52.

The role of approximate entropy in predicting ventricular defibrillation threshold. / Hamzei, Ali; Ohara, Toshihiko; Kim, Young Hoon; Lee, Moon Hyoung; Voroshilovski, Olga; Lin, Shien-Fong; Weiss, James N.; Chen, Peng-Sheng; Karagueuzian, Hrayr S.

In: Journal of Cardiovascular Pharmacology and Therapeutics, Vol. 7, No. 1, 2002, p. 45-52.

Research output: Contribution to journalArticle

Hamzei, A, Ohara, T, Kim, YH, Lee, MH, Voroshilovski, O, Lin, S-F, Weiss, JN, Chen, P-S & Karagueuzian, HS 2002, 'The role of approximate entropy in predicting ventricular defibrillation threshold', Journal of Cardiovascular Pharmacology and Therapeutics, vol. 7, no. 1, pp. 45-52.
Hamzei, Ali ; Ohara, Toshihiko ; Kim, Young Hoon ; Lee, Moon Hyoung ; Voroshilovski, Olga ; Lin, Shien-Fong ; Weiss, James N. ; Chen, Peng-Sheng ; Karagueuzian, Hrayr S. / The role of approximate entropy in predicting ventricular defibrillation threshold. In: Journal of Cardiovascular Pharmacology and Therapeutics. 2002 ; Vol. 7, No. 1. pp. 45-52.
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AU - Ohara, Toshihiko

AU - Kim, Young Hoon

AU - Lee, Moon Hyoung

AU - Voroshilovski, Olga

AU - Lin, Shien-Fong

AU - Weiss, James N.

AU - Chen, Peng-Sheng

AU - Karagueuzian, Hrayr S.

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N2 - Background: The role of myocardial tissue mass on ventricular defibrillation threshold (DFT) is unclear. We hypothesized that changes in tissue mass modulate DFT by changing ventricular fibrillation (VF) wavefront regularity (entropy). Methods and Results: The right ventricles (RV) of seven farm pigs were isolated, superfused and perfused through the right coronary artery with oxygenated Tyrode's solution at 37°C. The epicardial surface was stained with the voltage sensitive dye, di-4-ANEPPS, and activation wavefront numbers (AWN) during VF were determined from the optical maps using a CCD camera (96 × 96 pixels over a 3.5 × 3.5 cm area). The RV mass was progressively reduced by sequential cutting of 1 to 2 g of tissue (approximately 12 cuts in total) distal to the perfusion site. After each cut, VF was reinduced, optical maps obtained, and the 50% probability of successful DFT50 determined using an up-down algorithm. After each cut, the approximate entropy (ApEn) was also computed using 5 seconds of VF data obtained with a bipolar electrode and a pseudo-electrocardiogram. Tissue mass reduction of up to one third of the RV mass (ie, from 48.4 ± 4.25 g to 34 ± 4.7 g) caused little or no change in the DFT, ApEn or AWN. However, further progressive reduction of the RV mass near the critical mass of VF resulted in a significant (P <0.05) progressive decrease in all three measured parameters. DFT energy was reduced by 27% (1.47 ± 0.34 J vs. 1.02 ± 0.14 J). There was a significant (P <0.01) correlation between the DFT and ApEn, which significantly further increased (P <0.001) near the critical mass. In a separate series of 6 isolated RVs, the ApEn correlated well with the Kolmogorov-Sinai (K-S) entropy, the standard method of calculating entropy. Conclusion: Tissue mass reduction significantly reduces DFT when the mass reduction increases VF wavefront regularity.

AB - Background: The role of myocardial tissue mass on ventricular defibrillation threshold (DFT) is unclear. We hypothesized that changes in tissue mass modulate DFT by changing ventricular fibrillation (VF) wavefront regularity (entropy). Methods and Results: The right ventricles (RV) of seven farm pigs were isolated, superfused and perfused through the right coronary artery with oxygenated Tyrode's solution at 37°C. The epicardial surface was stained with the voltage sensitive dye, di-4-ANEPPS, and activation wavefront numbers (AWN) during VF were determined from the optical maps using a CCD camera (96 × 96 pixels over a 3.5 × 3.5 cm area). The RV mass was progressively reduced by sequential cutting of 1 to 2 g of tissue (approximately 12 cuts in total) distal to the perfusion site. After each cut, VF was reinduced, optical maps obtained, and the 50% probability of successful DFT50 determined using an up-down algorithm. After each cut, the approximate entropy (ApEn) was also computed using 5 seconds of VF data obtained with a bipolar electrode and a pseudo-electrocardiogram. Tissue mass reduction of up to one third of the RV mass (ie, from 48.4 ± 4.25 g to 34 ± 4.7 g) caused little or no change in the DFT, ApEn or AWN. However, further progressive reduction of the RV mass near the critical mass of VF resulted in a significant (P <0.05) progressive decrease in all three measured parameters. DFT energy was reduced by 27% (1.47 ± 0.34 J vs. 1.02 ± 0.14 J). There was a significant (P <0.01) correlation between the DFT and ApEn, which significantly further increased (P <0.001) near the critical mass. In a separate series of 6 isolated RVs, the ApEn correlated well with the Kolmogorov-Sinai (K-S) entropy, the standard method of calculating entropy. Conclusion: Tissue mass reduction significantly reduces DFT when the mass reduction increases VF wavefront regularity.

KW - Approximate entropy

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KW - Ventricular fibrillation

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