RESUMEN
BACKGROUND: Prolongation of the PQ interval, generally associated with an atrioventricular conduction delay, may be related to changes in intraventricular impulse spreading. OBJECTIVE: To assess, using body surface potential mapping (BSPM), the process of ventricular depolarization in athletes with prolonged PQ intervals at rest and after exercise. METHODS: The study included 7 cross-country skiers with a PQ interval of more than 200 ms (Prolonged-PQ group) and 7 with a PQ interval of less than 200 ms (Normal-PQ group). The BSPM from 64 unipolar torso leads was performed before (Pre-Ex) and after the bicycle exercise test (Post-Ex). Body surface equipotential maps were analyzed during ventricular depolarization. The significance level was 5%. RESULTS: Compared to Normal-PQ athletes, the first and second periods of the stable position of cardiac potentials on the torso surface were longer, and the formation of the "saddle" potential distribution occurred later, at Pre-Ex, in Prolonged-PQ athletes. At Post-Ex, the Prolonged-PQ group showed a shortening of the first and second periods of stable potential distributions and a decrease in appearance time of the "saddle" phenomenon relative to Pre-Ex (to the values near to those of the Normal-PQ group). Additionally, at Post-Ex, the first inversion of potential distributions and the total duration of ventricular depolarization in Prolonged-PQ athletes decreased compared to Pre-Ex and with similar values in Normal-PQ athletes. Compared to Normal-PQ athletes, the second inversion was longer at Pre-Ex and Post-Ex in Prolonged-PQ athletes. CONCLUSION: Prolonged-PQ athletes had significant differences in the temporal characteristics of BSPM during ventricular depolarization both at rest and after exercise as compared to Normal-PQ athletes.
FUNDAMENTO: O prolongamento do intervalo PQ, geralmente associado a um atraso na condução atrioventricular, pode estar relacionado a alterações na propagação do impulso intraventricular. OBJETIVO: Avaliar, por meio do mapeamento do potencial de superfície corporal (BSPM), o processo de despolarização ventricular em atletas com intervalos PQ prolongados em repouso e após o exercício. MÉTODOS: O estudo incluiu 7 esquiadores cross-country com intervalo PQ superior a 200 ms (grupo PQ Prolongado) e 7 com intervalo PQ inferior a 200 ms (grupo PQ Normal). O BSPM de 64 derivações unipolares do tronco foi realizado antes (Pré-Ex) e após o teste ergométrico de bicicleta (Pós-Ex). Mapas equipotenciais da superfície corporal foram analisados durante a despolarização ventricular. O nível de significância foi de 5%. RESULTADOS: Comparado com atletas com PQ Normal, o primeiro e o segundo períodos de posição estável dos potenciais cardíacos na superfície do tronco foram mais longos, e a formação da distribuição de potencial "sela" ocorreu mais tarde, no Pré-Ex, nos atletas com PQ Prolongado. No Pós-Ex, o grupo PQ Prolongado apresentou um encurtamento do primeiro e segundo períodos de distribuições de potencial estáveis e uma diminuição no tempo de aparecimento do fenômeno "sela" em relação ao Pré-Ex (para valores próximos aos do Normal -Grupo PQ). Além disso, no Pós-Ex, a primeira inversão das distribuições de potencial e a duração total da despolarização ventricular em atletas com PQ Prolongado diminuíram em comparação com o Pré-Ex e com valores semelhantes em atletas com PQ Normal. Em comparação com atletas com PQ Normal, a segunda inversão foi mais longa no Pré-Ex e Pós-Ex em atletas com PQ Prolongado. CONCLUSÃO: Atletas com PQ prolongado apresentaram diferenças significativas nas características temporais do BSPM durante a despolarização ventricular, tanto em repouso quanto após o exercício, em comparação com atletas com PQ normal.
Asunto(s)
Mapeo del Potencial de Superficie Corporal , Ejercicio Físico , Humanos , Potenciales de Acción , Corazón , AtletasRESUMEN
Resumo Fundamento: O prolongamento do intervalo PQ, geralmente associado a um atraso na condução atrioventricular, pode estar relacionado a alterações na propagação do impulso intraventricular. Objetivo: Avaliar, por meio do mapeamento do potencial de superfície corporal (BSPM), o processo de despolarização ventricular em atletas com intervalos PQ prolongados em repouso e após o exercício. Métodos: O estudo incluiu 7 esquiadores cross-country com intervalo PQ superior a 200 ms (grupo PQ Prolongado) e 7 com intervalo PQ inferior a 200 ms (grupo PQ Normal). O BSPM de 64 derivações unipolares do tronco foi realizado antes (Pré-Ex) e após o teste ergométrico de bicicleta (Pós-Ex). Mapas equipotenciais da superfície corporal foram analisados durante a despolarização ventricular. O nível de significância foi de 5%. Resultados: Comparado com atletas com PQ Normal, o primeiro e o segundo períodos de posição estável dos potenciais cardíacos na superfície do tronco foram mais longos, e a formação da distribuição de potencial "sela" ocorreu mais tarde, no Pré-Ex, nos atletas com PQ Prolongado. No Pós-Ex, o grupo PQ Prolongado apresentou um encurtamento do primeiro e segundo períodos de distribuições de potencial estáveis e uma diminuição no tempo de aparecimento do fenômeno "sela" em relação ao Pré-Ex (para valores próximos aos do Normal -Grupo PQ). Além disso, no Pós-Ex, a primeira inversão das distribuições de potencial e a duração total da despolarização ventricular em atletas com PQ Prolongado diminuíram em comparação com o Pré-Ex e com valores semelhantes em atletas com PQ Normal. Em comparação com atletas com PQ Normal, a segunda inversão foi mais longa no Pré-Ex e Pós-Ex em atletas com PQ Prolongado. Conclusão: Atletas com PQ prolongado apresentaram diferenças significativas nas características temporais do BSPM durante a despolarização ventricular, tanto em repouso quanto após o exercício, em comparação com atletas com PQ normal.
Abstract Background: Prolongation of the PQ interval, generally associated with an atrioventricular conduction delay, may be related to changes in intraventricular impulse spreading. Objective: To assess, using body surface potential mapping (BSPM), the process of ventricular depolarization in athletes with prolonged PQ intervals at rest and after exercise. Methods: The study included 7 cross-country skiers with a PQ interval of more than 200 ms (Prolonged-PQ group) and 7 with a PQ interval of less than 200 ms (Normal-PQ group). The BSPM from 64 unipolar torso leads was performed before (Pre-Ex) and after the bicycle exercise test (Post-Ex). Body surface equipotential maps were analyzed during ventricular depolarization. The significance level was 5%. Results: Compared to Normal-PQ athletes, the first and second periods of the stable position of cardiac potentials on the torso surface were longer, and the formation of the "saddle" potential distribution occurred later, at Pre-Ex, in Prolonged-PQ athletes. At Post-Ex, the Prolonged-PQ group showed a shortening of the first and second periods of stable potential distributions and a decrease in appearance time of the "saddle" phenomenon relative to Pre-Ex (to the values near to those of the Normal-PQ group). Additionally, at Post-Ex, the first inversion of potential distributions and the total duration of ventricular depolarization in Prolonged-PQ athletes decreased compared to Pre-Ex and with similar values in Normal-PQ athletes. Compared to Normal-PQ athletes, the second inversion was longer at Pre-Ex and Post-Ex in Prolonged-PQ athletes. Conclusion: Prolonged-PQ athletes had significant differences in the temporal characteristics of BSPM during ventricular depolarization both at rest and after exercise as compared to Normal-PQ athletes.
RESUMEN
Ivonina, Natalya I., Andrey A. Fokin, and Irina M. Roshchevskaya. Body surface potential mapping during heart ventricular repolarization in male swimmers and untrained persons under hypoxic and hypercapnic hypoxia. High Alt Med Biol. 22:308-316, 2021. Background: In swimmers, as a result of prolonged breath-holding during swimming, first hypoxic hypoxia (HH) and then hypercapnic hypoxia (HCH) occurs, which may influence the electrical activity of the heart (EAH). What type of normobaric hypoxia more strongly affects the EAH-normocapnic HH or HCH? Methods: The electrical activity of swimmers' hearts (n = 7) and untrained persons (n = 10) was studied by using electrocardiography (ECG) and body surface potential mapping (BSPM) during the period of ventricular repolarization at baseline, at normocapnic HH, at HCH, and in the recovery period. Results: HH led to more significant changes in the EAH in all participants in comparison with HCH. There was no change in the amplitude of T waveECG at hypoxic and HCH, but a change in the amplitude of the minimum was noted in BSPM. The minimum in athletes changed by the end of the exposure (from -0.40 ± 0.12 mV to -0.26 ± 0.11 mV, p = 0.001); in the control, it decreased earlier (after 8 minutes of exposure to HH, the amplitude of the minimum was -0.24 ± 0.08 mV, p = 0.026). With HH, the duration of the QT interval in athletes was shortened due to the shortening of the J-Tpeak (from 250 to 188 ms, p = 0.001) and the Tpeak-Tend (from 98 to 86 ms) intervals. In controls, the decrease in the QT interval was due to the J-Tpeak shortening only (from 280 to 200 ms, p = 0.026). Conclusions: In the study of the effect of hypoxia on the EAH during ventricular repolarization, the use of the BSPM has proven to be more informative than the use of traditional ECG. When using potential mapping, more significant changes in ventricular repolarization at HH than at HCH were revealed, whereas the parameters changed less in swimmers compared with the baseline than in controls during both exposures.
