Alteration of Ventricular Fibrillation by Flecainide, Verapamil, and Sotalol

Background—The purpose of this study was to determine whether the myocardial electrophysiological properties are useful for predicting changes in the ventricular fibrillatory pattern. Methods and Results—Thirty-two Langendorff-perfused rabbit hearts were used to record ventricular fibrillatory activity with an epicardial multiple electrode. Under control conditions and after flecainide, verapamil, or d,l-sotalol, the dominant frequency (FrD), type of activation maps, conduction velocity, functional refractory period, and wavelength (WL) of excitation were determined during ventricular fibrillation (VF). Flecainide (1.9±0.3 versus 2.4±0.6 cm, P<0.05) and sotalol (2.1±0.3 versus 2.5±0.5 cm, P<0.05) prolonged WL and diminished FrD during VF, whereas verapamil (2.0±0.2 versus 1.7±0.2 cm, P<0.001) shortened WL and increased FrD. Simple linear regression revealed an inverse relation between FrD and the functional refractory period (r=0.66, P<0.0001), a direct relation with respect to conduction velocity (r=0.33, P<0.01), and an inverse relation with respect to WL estimated during VF (r=0.49, P<0.0001). By stepwise multiple regression, the functional refractory periods were the only predictors of FrD. Flecainide and sotalol increased the circuit size of the reentrant activations, whereas verapamil decreased it. The 3 drugs significantly reduced the percentages of more complex activation maps during VF. Conclusions—The activation frequency is inversely related to WL during VF, although a closer relation is observed with the functional refractory period. Despite the diverging effects of verapamil versus flecainide and sotalol on the activation frequency, WL, and size of the reentrant circuits, all 3 drugs reduce activation pattern complexity during VF.Chorro Gasco, Francisco Javier, [email protected] ; Guerrero Martinez, Juan Francisco, [email protected] ; Sanchis Fores, Juan, [email protected] ; Such Belenguer, Luis, [email protected]

Análisis del efecto del ejercicio físico en la homogeneidad espacial del espectro de la señal de fibrilación ventricular

El presente trabajo estudia las modificaciones intrínsecas que el ejercicio físico produce en la respuesta cardíaca durante fibrilación ventricular (FV), tanto en condiciones de perfusión estable como cuando se produce isquemia en una zona del miocardio. Se estudiarán dichas modificaciones comparándolas con las producidas por el efecto de un fármaco (Glibenclamida) y con un grupo control. El análisis se realizará desde el punto de vista del dominio frecuencial, estudiando la homogeneidad espacial de la frecuencia dominante (ROIsaFD) y de la energía normalizada (ROIsaEN), en registros de cartografía cardíaca unipolar de corazón aislado de conejo. Se utilizarán tres grupos de conejos: control (GC: sin entrenamiento, N=18), entrenados (GE: N=9) y fármaco (GF: sin entrenamiento, con tratamiento, N=15). Se realizarán comparaciones intergrupos, teniendo en cuenta el hecho de que se realizan medidas repetidas en el tiempo, y se harán comparaciones intragrupos para estudiar el efecto del tiempo. Los resultados obtenidos sugieren que los efectos intrínsecos producidos por ejercicio físico sobre la homogeneidad espacial de la respuesta espectral de la FV son similares a los producidos por el tratamiento con Glibenclamida, especialmente cuando se tienen zonas isquémicas

Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart

[EN] A study has been made of the effect of chronic exercise on myocardial electrophysiological heterogeneity and stability, as well as of the role of cholinergic neurons in these changes. Determinations in hearts from untrained and trained rabbits on a treadmill were performed. The hearts were isolated and perfused. A pacing electrode and a recording multielectrode were located in the left ventricle. The parameters determined during induced VF, before and after atropine (1 mu M), were: fibrillatory cycle length (VV), ventricular functional refractory period (FRPVF), normalized energy (NE) of the fibrillatory signal and its coefficient of variation (CV), and electrical ventricular activation complexity, as an approach to myocardial heterogeneity and stability. The VV interval was longer in the trained group than in the control group both prior to atropine (78 +/- 10 vs. 68 +/- 10 ms) and after atropine (76 +/- 8 vs. 67 +/- 10 ms). Likewise, FRPVF was longer in the trained group than in the control group both prior to and after atropine (53 +/- 8 vs. 42 +/- 7 ms and 50 +/- 6 vs. 40 +/- 6 ms, respectively), and atropine did not modify FRPVF. The CV of FRPVF was lower in the trained group than in the control group prior to atropine (12.5 +/- 1.5% vs. 15.1 +/- 3.8%) and, decreased after atropine (15.1 +/- 3.8% vs. 12.2 +/- 2.4%) in the control group. The trained group showed higher NE values before (0.40 +/- 0.04 vs. 0.36 +/- 0.05) and after atropine (0.37 +/- 0.04 vs. 0.34 +/- 0.06; p = 0.08). Training decreased the CV of NE both before (23.3 +/- 2% vs. 25.2 +/- 4%; p = 0.08) and after parasympathetic blockade (22.6 +/- 1% vs. 26.1 +/- 5%). Cholinergic blockade did not modify these parameters within the control and trained groups. Activation complexity was lower in the trained than in the control animals before atropine (34 +/- 8 vs. 41 +/- 5), and increased after atropine in the control group (41 +/- 5 vs. 48 +/- 9, respectively). Thus, training decreases the intrinsic heterogeneity of the myocardium, increases electrophysiological stability, and prevents some modifications due to muscarinic block.This research was supported by the Spanish Ministry of Education and Science, (DEP2007-73234-C03-01 to AMA), http://www.mecd.gob.es/portada-mecd/; and the Generalitat Valenciana (PROMETEO 2010/093 to FJC, and FPI/2008/003 to MZ), http://www.gva.es/va/inicio/presentacion; jsessionid=ydprbDQZTsCTz85W1Such-Miquel, L.; Brines-Ferrando, L.; Alberola, A.; Zarzoso Muñoz, M.; Chorro Gasco, FJ.; Guerrero-Martínez, JF.; Parra-Giraldo, G.... (2018). Effect of chronic exercise on myocardial electrophysiological heterogeneity and stability. Role of intrinsic cholinergic neurons: A study in the isolated rabbit heart. PLoS ONE. 13(12). https://doi.org/10.1371/journal.pone.0209085S1312Billman, G. E. (2002). Aerobic exercise conditioning: a nonpharmacological antiarrhythmic intervention. Journal of Applied Physiology, 92(2), 446-454. doi:10.1152/japplphysiol.00874.2001Billman, G. E. (2006). A comprehensive review and analysis of 25 years of data from an in vivo canine model of sudden cardiac death: Implications for future anti-arrhythmic drug development. Pharmacology & Therapeutics, 111(3), 808-835. doi:10.1016/j.pharmthera.2006.01.002Dor-Haim, H., Berenfeld, O., Horowitz, M., Lotan, C., & Swissa, M. (2013). Reduced Ventricular Arrhythmogeneity and Increased Electrical Complexity in Normal Exercised Rats. PLoS ONE, 8(6), e66658. doi:10.1371/journal.pone.0066658Hamer, M., & Stamatakis, E. (2008). Physical Activity and Cardiovascular Disease: Directions for Future Research. The Open Sports Sciences Journal, 1(1), 1-2. doi:10.2174/1875399x00801010001Powers, S. K., Smuder, A. J., Kavazis, A. N., & Quindry, J. C. (2014). Mechanisms of Exercise-Induced Cardioprotection. Physiology, 29(1), 27-38. doi:10.1152/physiol.00030.2013Hull, S. S., Vanoli, E., Adamson, P. B., Verrier, R. L., Foreman, R. D., & Schwartz, P. J. (1994). Exercise training confers anticipatory protection from sudden death during acute myocardial ischemia. Circulation, 89(2), 548-552. doi:10.1161/01.cir.89.2.548Hajnal, Á., Nagy, O., Litvai, Á., Papp, J., Parratt, J. R., & Végh, Á. (2005). Nitric oxide involvement in the delayed antiarrhythmic effect of treadmill exercise in dogs. Life Sciences, 77(16), 1960-1971. doi:10.1016/j.lfs.2005.02.015Such, L., Alberola, A. M., Such-Miquel, L., López, L., Trapero, I., Pelechano, F., … Chorro, F. J. (2008). Effects of chronic exercise on myocardial refractoriness: a study on isolated rabbit heart. Acta Physiologica, 193(4), 331-339. doi:10.1111/j.1748-1716.2008.01851.xZarzoso, M., Such-Miquel, L., Parra, G., Brines-Ferrando, L., Such, L., Chorro, F. J., … Alberola, A. (2011). The training-induced changes on automatism, conduction and myocardial refractoriness are not mediated by parasympathetic postganglionic neurons activity. European Journal of Applied Physiology, 112(6), 2185-2193. doi:10.1007/s00421-011-2189-4Billman, G. E. (2009). Cardiac autonomic neural remodeling and susceptibility to sudden cardiac death: effect of endurance exercise training. American Journal of Physiology-Heart and Circulatory Physiology, 297(4), H1171-H1193. doi:10.1152/ajpheart.00534.2009HAN, J., & MOE, G. K. (1964). Nonuniform Recovery of Excitability in Ventricular Muscle. Circulation Research, 14(1), 44-60. doi:10.1161/01.res.14.1.44Beaumont, E., Salavatian, S., Southerland, E. M., Vinet, A., Jacquemet, V., Armour, J. A., & Ardell, J. L. (2013). Network interactions within the canine intrinsic cardiac nervous system: implications for reflex control of regional cardiac function. The Journal of Physiology, 591(18), 4515-4533. doi:10.1113/jphysiol.2013.259382Armour, J. A. (2008). Potential clinical relevance of the ‘little brain’ on the mammalian heart. Experimental Physiology, 93(2), 165-176. doi:10.1113/expphysiol.2007.041178Abramochkin, D. V., Nurullin, L. F., Borodinova, A. A., Tarasova, N. V., Sukhova, G. S., Nikolsky, E. E., & Rosenshtraukh, L. V. (2009). Non-quantal release of acetylcholine from parasympathetic nerve terminals in the right atrium of rats. Experimental Physiology, 95(2), 265-273. doi:10.1113/expphysiol.2009.050302CHORRO, F. J., CANOVES, J., GUERRERO, J., MAINAR, L., SANCHIS, J., SORIA, E., … LOPEZ-MERINO, V. (2000). Opposite Effects of Myocardial Stretch and Verapamil on the Complexity of the Ventricular Fibrillatory Pattern: An Experimental Study. Pacing and Clinical Electrophysiology, 23(11), 1594-1603. doi:10.1046/j.1460-9592.2000.01594.xSuch, L., Rodriguez, A., Alberola, A., Lopez, L., Ruiz, R., Artal, L., … Chorro, F. J. (2002). 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Effects of S-Nitrosoglutathione on Electrophysiological Manifestations of Mechanoelectric Feedback

[EN] Electromechanical coupling studies have described the intervention of nitric oxide and S-nitrosylation processes in Ca2+ release induced by stretch, with heterogeneous findings. On the other hand, ion channel function activated by stretch is influenced by nitric oxide, and concentration-dependent biphasic effects upon several cellular functions have been described. The present study uses isolated and perfused rabbit hearts to investigate the changes in mechanoelectric feedback produced by two different concentrations of the nitric oxide carrier S-nitrosoglutathione. Epicardial multielectrodes were used to record myocardial activation at baseline and during and after left ventricular free wall stretch using an intraventricular device. Three experimental series were studied: (a) control (n=10); (b) S-nitrosoglutathione 10 mu M (n=11); and (c) S-nitrosoglutathione 50 mu M (n=11). The changes in ventricular fibrillation (VF) pattern induced by stretch were analyzed and compared. S-nitrosoglutathione 10 mu M did not modify VF at baseline, but attenuated acceleration of the arrhythmia (15.6 +/- 1.7 vs. 21.3 +/- 3.8Hz; p<0.0001) and reduction of percentile 5 of the activation intervals (42 +/- 3 vs. 38 +/- 4ms; p<0.05) induced by stretch. In contrast, at baseline using the 50 mu M concentration, percentile 5 was shortened (38 +/- 6 vs. 52 +/- 10ms; p<0.005) and the complexity index increased (1.77 +/- 0.18 vs. 1.27 +/- 0.13; p<0.0001). The greatest complexity indices (1.84 +/- 0.17; p<0.05) were obtained during stretch in this series. S-nitrosoglutathione 10 mu M attenuates the effects of mechanoelectric feedback, while at a concentration of 50 mu M the drug alters the baseline VF pattern and accentuates the increase in complexity of the arrhythmia induced by myocardial stretch.Carlos III Health Institute/FEDER funds (Spanish Ministry of Economy and Competitiveness): Grants FIS PI12/00407, PI15/01408, PIE15/00013, and RETIC “RIC” RD12/0042/0048. 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The role of nitric oxide and reactive oxygen species in the positive inotropic response to mechanical stretch in the mammalian myocardium. Biochimica Biophysica Acta, 1787, 811–817.Sag, C. M., Wagner, S., & Maier, L. S. (2013). Role of oxidants on calcium and sodium movement in healthy and diseased cardiac myocytes. Free Radical Biology and Medicine, 63, 338–349.Janvier, N. C., & Boyett, M. R. (1996). The role of Na-Ca exchange current in the cardiac action potential. Cardiovascular Research, 32, 69–84.Kovács, M., Kiss, A., Gönczi, M., Miskolczi, G., Seprényl, G., Kaszaki, J., Kohr, M. J., Murphy, E., & Vegh, A. (2015). Effect of sodium nitrite on ischaemia and reperfusion-induced arrhythmias in anaesthetized dogs: Is protein S-nitrosylation involved? PLoS ONE, 10(4), e0122243 (eCollection 2015). https://doi.org/10.1371/journal.pone.0122243

Effects of Physical Exercise and Glibenclamide on Local Activation Waves during Ventricular Fibrillation

Abstrac

Effects of the inhibition of late sodium current by GS967 on stretch-induced changes in cardiac electrophysiology

[EN] PurposeMechanical stretch increases sodium and calcium entry into myocytes and activates the late sodium current. GS967, a triazolopyridine derivative, is a sodium channel blocker with preferential effects on the late sodium current. The present study evaluates whether GS967 inhibits or modulates the arrhythmogenic electrophysiological effects of myocardial stretch.MethodsAtrial and ventricular refractoriness and ventricular fibrillation modifications induced by acute stretch were studied in Langendorff-perfused rabbit hearts (n=28) using epicardial multiple electrodes and high-resolution mapping techniques under control conditions and during the perfusion of GS967 at different concentrations (0.03, 0.1, and 0.3M).ResultsOn comparing ventricular refractoriness, conduction velocity and wavelength obtained before stretch had no significant changes under each GS967 concentration while atrial refractoriness increased under GS967 0.3M. Under GS967, the stretch-induced changes were attenuated, and no significant differences were observed between before and during stretch. GS967 0.3M diminished the normal stretch-induced changes resulting in longer (less shortened) atrial refractoriness (13826ms vs 95 +/- 9ms; p<0.01), ventricular refractoriness (155 +/- 18ms vs 124 +/- 16 ms; p<0.01) and increments in spectral concentration (23 +/- 5% vs 17 +/- 2%; p<0.01), the fifth percentile of ventricular activation intervals (46 +/- 8ms vs 31 +/- 3ms; p<0.05), and wavelength of ventricular fibrillation (2.5 +/- 0.5cm vs 1.7 +/- 0.3cm; p<0.05) during stretch. The stretch-induced increments in dominant frequency during ventricular fibrillation (control=38%, 0.03M=33%, 0.1M=33%, 0.3M=14%; p<0.01) and the stretch-induced increments in arrhythmia complexity index (control=62%, 0.03M=41%, 0.1M=32%, 0.3M=16%; p<0.05) progressively decreased on increasing the GS967 concentration.Conclusions GS967 attenuates stretch-induced changes in cardiac electrophysiology.This work was supported by the Spanish Ministry of Economy and Competiveness (Carlos III Health Institute)/European Regional Development Fund (FEDER) (Grants FIS PI12/00407, PI15/01408, PIE15/00013, CB16/11/00486) and by the Generalitat Valenciana (Grant PROMETEO FASE II 2014/037).Canto Serrano, ID.; Santamaría, L.; Genovés, P.; Such-Miquel, L.; Arias-Mutis, ÓJ.; Zarzoso Muñoz, M.; Soler, C.... (2018). Effects of the inhibition of late sodium current by GS967 on stretch-induced changes in cardiac electrophysiology. 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Nuevo péptido inhibidor del intercambiador NA4+H+ (pinhe), y sus aplicaciones.

Fecha de solicitud: 15.07.2003.- Titulares: Consejo Superior de Investigaciones Científicas (CSIC).- Universidad de Valencia.- Universidad Miguel Hernández.[EN]The invention relates to a peptide (PINHE) comprising 28 amino acids, which is obtained by fractionation and purification of the supernatant of the culture of Haloferax gibbonsii alicante SPH7. PINHE acts as a natural physiological inhibitor of the Na/H exchanger in eukaryotes. Moreover, PINHE is active in wide ranges of saline concentrations, temperature and pH as well as being trypsin resistant and pronase sensitive. Owing to the reversible action of said peptide on the Na/H exchanger, it can be used (1) for the treatment or prophylaxis of pathologies such as cardiovascular, renal, cerebral and metabolic diseases, pathological proliferative processes, hyperproduction of hydrochloric acid, etc. and (2) for other diseases or pathologies associated with a post-ischemic reperfusion lesion and ischemia caused by hyperactivity of the NHE, such as ischemias caused by primary or secondary vascular alterations in different tissues, by post-infarction reperfusion, by an organ or tissue transplant, etc. The inventive peptide can also be used as a contraceptive (in male mammals), an antibiotic or an immunoregulatory agent and in plants as a saline stress modulator. [ES]La presente invención describe un péptido (PINHE) constituido por 28 aminoácidos obtenido por fraccionamiento y purificación del sobrenadante del cultivo de Haloferax gibbonsii alicante SPH7. El PINHE actúa como inhibidor fisiológico natural del intercambiador Na+/H+ en eucariotas. Es activo en rangos amplios de concentraciones salinas, temperatura y pH, resistente a tripsina y sensible a pronasa. De su acción reversible sobre el intercambiador Na+/H+ se deriva: (1) su uso para el tratamiento o profilaxis de patologías como enfermedades cardiovasculares, renales, cerebrales, metabólicas, procesos proliferativos patológicos, hiperproducción de ácido clorhídrico, etc., (2) en otras enfermedades o patologías que cursen con isquemia y lesión por reperfusión post-isquémica debida a la hiperactividad del NHE como isquemias por alteraciones vasculares primarias o secundarias en diversos tejidos, por reperfusión post-infarto, por transplante de órganos o tejidos, etc. También como contraceptivo (en mamíferos macho), antibiótico o agente inmunorregulador, y en plantas como modulador del estrés salino.Peer reviewe

Una halocina que actúa sobre el intercambiador Na+/H+ de Haloarchaea como un nuevo tipo de inhibidor de NHE de mamíferos

10 páginas, 3 figuras.[EN]: The capability of halocin H6 (a bacteriocin-like protein produced by haloarchaeaHaloferax gibbonsii) to inhibit Na+/H+ exchange (NHE) in mammalian cells and its cardio-protective efficacy on the ischemic and reperfused myocardium were evaluated in the present study. H6 inhibits NHE activity (measured by a flow cytometry method) in a dose-dependent form of cell lines of mammalian origin (HEK293, NIH3T3, Jurkat and HL-1) as well as in primary cell culture from human skeletal muscle (myocytes and fibroblasts).In vivo, an ischemia-reperfusion model in dogs by coronary arterial occlusion was used (two hours of regional ischemia and three hours of reperfusion). In animals treated with halocin H6 there was a significant reduction of premature ventricular ectopic beats and infarct size, whereas blood pressure and heart rate remained unchanged. Up to date, halocin H6 is the only described biological molecule that exerts a, specific inhibitory activity in NHE of eukaryotic cells.[ES]: En el presente trabajo se evalúa la capacidad de la halocina H6 (una proteína tipo bacteriocina producida por la haloarchaea Haloferax gibbonsii) para inhibir el intercambiador Na+/H+ (NHE) de células de mamífero y su posible eficacia cardioprotectora frente a los daños causados por isquemia-reperfusión del miocardio. En experimentos in vitro H6 inhibe la actividad de NHE (determinada por citometría de flujo) de forma dosis-dependiente tanto en líneas celulares de mamíferos (HEK293, NIH3T3, Jurkat y HL-1) como en cultivos primarios de miocitos y fibroblastos aislados de músculo esquelético humano. En experimentos in vivo se utilizó un modelo de isquemia- reperfusión en perros por oclusión de la arteria coronaria (dos horas de isquemia y tres de reperfusión). En animales tratados con halocina H6 se produjo una disminución significativa a nivel estadístico, tanto del número de latidos ectópicos ventriculares como del tamaño del infarto, mientras que no se produjeron cambios tanto en la presión sanguínea como en el ritmo cardíaco. Hasta la fecha la halocina H6 es la única molécula biológica descrita que ejerce una actividad inhibidora específica sobre el NHE de células eucariotas.M. Dolz held a fellowship of CSIC-Bancaja Foundation. This work was supported in part by Spanish Council for Scientific Research (CSIC- 2001551).Peer reviewe