Applicability of Body Surface Potential Mapping Through Exercise in Small Animals

Keywords
Exercise; Physical Conditionning; Animal; Body Surface Potential Mapping; Myocardial; Rats; Heart Ventricle

The electrical potentials of the heart have been recorded for over a hundred years to represent the distribution of these internal electrical events on the torso surface. Such recordings that started with Waller tried to establish a resultant vector from a bipolar source, the “heart vector,” assuming that this distribution of potentials would act as if an electrical bipole was inserted inside the thorax and applied to the body surface, with a third electrode adding the sagittal component of the vector. The three would be enough to supply all the electrocardiogram (ECG) information extracted from measurements from the body surface. It was not until the 1930s and 1940s that the number of electrodes on the chest surface was tentatively increased to detect events occurring in cardiac areas near the precordial leads. Finally, after 1950 some studies demonstrated that the complexity of the electrical information generated inside the heart was far greater than that generated by a sole bipole, with multiple wavefronts in the ventricles creating currents that flow into and from the heart in several places; the potentials, therefore, would exhibit maximum and minimum distributions varying with time, usually located in areas unexplored by the conventional electrocardiogram.

New methodologies complementing the ECG and vectorcardiogram (ECG) added new electrodes (dorsal and right precordial leads), and, since Wilson, the 12-lead ECG started to have three bipolar and three unipolar modified leads in the frontal plane, in addition to six unipolar (precordial) leads on the anterior chest, which can record most of the information about electrical events in the heart. However, the myocardial electrical activity global expression cannot be captured without a larger number of simultaneously recorded leads.

The body surface potential mapping (BSPM) can provide, spatially and noninvasively, in great detail, both the electrical non-bipolar components and the bipolar component of the cardiac electrical activity. It is responsive to regional events inside the heart by capturing the distribution of potentials on the body surface and evaluating the various aspects within the cardiac field.

Manual assessment of a large number of electrograms recorded simultaneously demands computerized processing, and for this reason, it was only in the 1960s that the BSPM became usable in medical practice. Several systems were developed in the 1970s and 1980s to deploy electrodes across the torso.

In Brazil, the experience with the BSPM methodology began early in the 1990s,¹–³ when we could acquire the 87-lead Fukuda Denshi 7100 equipment, the first to be manufactured in the world; we were trained for its use at the manufacturer's premises in Japan (Tokyo).

During the last three decades, thereby, we developed pioneering studies in all the specialties of Cardiology, including our partnership with colleagues developing doctoral theses at InCor HCFMUSP.⁴–¹³

The Biomedical Engineering Department of InCor HCFMUSP has been working on the development of a fully nationalized 64-lead BSPM equipment since 2016, with the contribution of the Electrocardiography Unit of InCor.

The first experiences with the BSPM analysis with this new equipment, including vectorcardiography, have already been approved and published.¹⁴,¹⁵

The evolution of BSPM utilization has been very promising, especially from the experimental viewpoint, since it enables placing a much bigger number of electrodes than with standard ECG and forward evaluation of isopotential and isochronal maps.

In the article by the Russian group headed by Dr. Irina Roshchevskaya,¹⁶ who has deep knowledge in experimental work with Electrocardiography in small animals, we find interesting experiences, such as using BSPM in small animals with a very challenging adaptation of electrodes; this work brings us an innovative experience in this field.

The authors evaluated the electrical activity of the heart of untrained rats during ventricular depolarization after the performance of acute exhaustive exercises on a treadmill using the BSPM combined with the standard ECG.

Using isopotential maps obtained from the BSPM to assess the heart's electrical activity during ventricular depolarization is an extensively studied tool. The novelty of this study is the use of this resource in rats submitted to exhaustive physical exercise. BSPM evaluation of these animals under such conditions did not reveal any alteration of the spatial pattern of body surface potential distribution during ventricular depolarization. What could be seen was a decrease in the duration of the middle phase and in the overall duration of the ventricular depolarization, as well as in the amplitude of BSPM negative extremum.

The results showed that this activity causes reversible alterations of BSPM temporal features and amplitudes during ventricular depolarization, which are related to alterations of the main ventricular myocardial mass excitability. These findings may contribute to the analysis of cardiac electrical activation in high-performance athletes.

• Short Editorial related to the article: Body Surface Potential Mapping during Ventricular Depolarization in Rats after Acute Exhaustive Exercise

Referências

• ¹
  Pastore CA. Mapeamento eletrocardiográfico de Superfície na localização de vias acessórias na síndrome de Wolff-Parkinson-White. [Tese]. São Paulo: Universidade de São Paulo. Faculdade de Medicina;1992.
• ²
  Pastore CA, Moffa PJ. Aspectos técnicos e aplicações clínicas do mapeamento eletrocardiográfico de superfície (Body Surface Mapping). Arq Bras Cardiol. 1992;58(5):391-7.
• ³
  Pastore CA, Moffa PJ. Body surface potential mapping to identify localization of ventricular insertion of accessory pathways in Wolff-Parkinson-White syndrome. In: Proceedings of the XXth International Congress on Electrocardiology./by /Macfarlane PW, Rautaharju P (eds). Singapore: World Scientific;Publishing Co; 1993. p:161-4 (Publishing Co;19931993)
• ⁴
  Pastore CA, Moffa P, Tobias N, Silva HB, Bortolotto LA, et al. Body surface potential mapping in malignant hypertension. Jap Heart J. 1994;35(Suppl):505-6.
• ⁵
  Tranchesi Jr B, Kalil Filho R, Forlenza LMA, Chacra AP, Abaurre P, Patrício M, et al. The importance of body surface potential mapping in the diagnosis of right ventricular infarction. In: 12 World Congress of Cardiology/ 16 Congress of the European Society of Cardiology. Berlim; Sept 1994.Eur Heart J.1994;15(Suppl):1-615. doi: 10.1093/eurheartj/15.Abstract_Supplement
  » https://doi.org/10.1093/eurheartj/15.Abstract_Supplement
• ⁶
  Pastore CA, Moffa PJ, Tobias NM, Moraes AG, Kaiser E, Cuoco MA, et al. Análise do bloqueio do ramo esquerdo pelo mapeamento eletrocardiográfico de superfície. Comparação com os achados eletro-vetorcardiográficos. Arq Bras Cardiol. 1996;66(5):253-6. PMID: 9008906
• ⁷
  Douglas R.A.G, Samesima N, Martinelli Filho M, Pedrosa AA, Nishioka SAD,. Pastore CA, et al. Global and regional ventricular repolarization study by body surface potential mapping in patients with left bundle-branch block and heart failure undergoing cardiac resynchronization therapy. Ann Noninvas Electrocardiol. 2012;17(2):123-9. PMID: 22537330
• ⁸
  Samesima N, Pastore CA, Douglas RA, Martinelli Filho, M., Pedrosa, A.A. Improved relationship between left and right ventricular electrical activation after cardiac resynchronization therapy in heart failure patients can be quantified by body surface potential mapping. Clinic. 2013;68 (7):986-91.
• ⁹
  Pastore CA, Tobias N, Kaiser E, Bacal F, Aziz JL, Moreira LLFP, et al. Electrocardiographic and vectorcardiographic findings of patients undergoing reductive ventriculectomy (Batista operation). Clin Cardiol. (Mahwah), 2003;26:36-42.
• ¹⁰
  Pastore CA, Arcêncio SR, Tobias N, Kaiser E, Martinelli Filho M, Moreira, LFP, et al. QT interval dispersion analysis in patients undergoing left partial ventriculectomy (Batista operation). Ann Noninvas Electrocardiol. 2004;9(4):375-82. doi: 10.1111/j.1542-474X.2004.94582.x.
  » https://doi.org/10.1111/j.1542-474X.2004.94582.x
• ¹¹
  De Carvalho FC, Consolim-Colombo FM, Pastore CA, Rubira MC, Menegüetti, J, Krieger EM, et al. Acute reduction of ventricular volume decreases QT interval dispersion in elderly subjects with and without heart failure. Am J Physiol. - Heart Circ Physiol.2005;288 (5 57-5):H2171-H2176.
• ¹²
  Pastore CA, Tobias N, Samesima N, Martinelli Filho M, Pedrosa, A., Nishioka, S. et al. Body surface potential mapping investigating the ventricular activation patterns in the cardiac resynchronization of patients with left bundle-branch block and heart failure. J Electrocardiol. 2006;39(1):93-102 doi: 10.1016/j.jelectrocard.2005.07.004.
  » https://doi.org/10.1016/j.jelectrocard.2005.07.004
• ¹³
  Pastore CA, Tobias N, Samesima, Martinelli Filho M., Pedrosa A, Nishioka S, et al. Ventricular electrical activation in cardiac resynchronization as characterized by body surface potential mapping. Arq Bras Cardiol. 2007;88(3):223-8, 251-7. DOI: 10.1590/s0066-782x2007000300001
  » https://doi.org/10.1590/s0066-782x2007000300001
• ¹⁴
  Salinet JL, Marques V, Mazzetto M, Camargo ED, Pastore, C.A., Cestari IA. A 64-lead body surface potential mapping system. Comput Cardiol 2017;44:1-4.
• ¹⁵
  Salinet J, Paredes JGS, Tobias N, Marques VG, Samesima, N, Pastore CA., Cestari, I.A. Non-Invasive Characterization of Cardiac Activation Patterns: Contributions of Body Surface Potential Mapping in Healthy Volunteers. Comput Cardiol. Sept.2019. art. no. 9005509.
• ¹⁶
  Ivonin AG, Smirnova SL, Roshchevskaya IM. Body Surface Potential Mapping during Ventricular Depolarization in Rats after Acute Exhaustive Exercise]. Arq Bras Cardiol. 2022; 119(5):766-775.

Publication Dates

• Publication in this collection
  25 Nov 2022
• Date of issue
  Nov 2022