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. 1990 Oct;429:387–400. doi: 10.1113/jphysiol.1990.sp018263

Regional changes in ventricular excitability during load manipulation of the in situ pig heart.

J W Dean 1, M J Lab 1
PMCID: PMC1181706  PMID: 2277353

Abstract

1. The effect of load manipulation on myocardial excitability was studied in the anaesthetized, in situ pig heart. 2. A 33% increase in systolic left ventricular pressure achieved by aortic clamping reduced the mean effective refractory period by 11 ms (7.6%, P less than 0.01); whereas a 15% reduction in ventricular pressure achieved by intravenous infusion of sodium nitroprusside increased the mean effective refractory period by 4 ms (3.2%, P less than 0.05). 3. Changes in action potential duration, measured to 70% repolarization, roughly paralleled those of the effective refractory period. 4. The changes in effective refractory period were inhomogeneous, with a greater change occurring at the apex compared to the base in response to an increase in load, i.e. there was an increase in regional dispersion of refractoriness across the left ventricle. 5. Since inhomogeneity of repolarization and refractoriness is known to be potentially arrhythmogenic, these findings suggest that mechanical factors may contribute directly to the arrhythmias commonly seen clinically in high load states such as congestive cardiac failure and may also have consequences for the treatment of such arrhythmias.

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Selected References

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  1. Allen D. G., Nichols C. G., Smith G. L. The effects of changes in muscle length during diastole on the calcium transient in ferret ventricular muscle. J Physiol. 1988 Dec;406:359–370. doi: 10.1113/jphysiol.1988.sp017385. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. BLUMENTHAL M. R., WANG H. H., WANG S. C. Effect of acute experimental aortic stenosis on coronary circulation. Circ Res. 1962 Oct;11:727–735. doi: 10.1161/01.res.11.4.727. [DOI] [PubMed] [Google Scholar]
  3. Bassingthwaighte J. B., Fry C. H., McGuigan J. A. Relationship between internal calcium and outward current in mammalian ventricular muscle; a mechanism for the control of the action potential duration? J Physiol. 1976 Oct;262(1):15–37. doi: 10.1113/jphysiol.1976.sp011583. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Calkins H., Maughan W. L., Kass D. A., Sagawa K., Levine J. H. Electrophysiological effect of volume load in isolated canine hearts. Am J Physiol. 1989 Jun;256(6 Pt 2):H1697–H1706. doi: 10.1152/ajpheart.1989.256.6.H1697. [DOI] [PubMed] [Google Scholar]
  5. Calkins H., Maughan W. L., Weisman H. F., Sugiura S., Sagawa K., Levine J. H. Effect of acute volume load on refractoriness and arrhythmia development in isolated, chronically infarcted canine hearts. Circulation. 1989 Mar;79(3):687–697. doi: 10.1161/01.cir.79.3.687. [DOI] [PubMed] [Google Scholar]
  6. Cleland J. G., Dargie H. J., Ball S. G., Gillen G., Hodsman G. P., Morton J. J., East B. W., Robertson I., Ford I., Robertson J. I. Effects of enalapril in heart failure: a double blind study of effects on exercise performance, renal function, hormones, and metabolic state. Br Heart J. 1985 Sep;54(3):305–312. doi: 10.1136/hrt.54.3.305. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Cohn J. N., Archibald D. G., Ziesche S., Franciosa J. A., Harston W. E., Tristani F. E., Dunkman W. B., Jacobs W., Francis G. S., Flohr K. H. Effect of vasodilator therapy on mortality in chronic congestive heart failure. Results of a Veterans Administration Cooperative Study. N Engl J Med. 1986 Jun 12;314(24):1547–1552. doi: 10.1056/NEJM198606123142404. [DOI] [PubMed] [Google Scholar]
  8. Colquhoun D., Neher E., Reuter H., Stevens C. F. Inward current channels activated by intracellular Ca in cultured cardiac cells. Nature. 1981 Dec 24;294(5843):752–754. doi: 10.1038/294752a0. [DOI] [PubMed] [Google Scholar]
  9. Dean J. W., Lab M. J. Arrhythmia in heart failure: role of mechanically induced changes in electrophysiology. Lancet. 1989 Jun 10;1(8650):1309–1312. doi: 10.1016/s0140-6736(89)92697-4. [DOI] [PubMed] [Google Scholar]
  10. Franz M. R., Burkhoff D., Yue D. T., Sagawa K. Mechanically induced action potential changes and arrhythmia in isolated and in situ canine hearts. Cardiovasc Res. 1989 Mar;23(3):213–223. doi: 10.1093/cvr/23.3.213. [DOI] [PubMed] [Google Scholar]
  11. HAN J., MOE G. K. NONUNIFORM RECOVERY OF EXCITABILITY IN VENTRICULAR MUSCLE. Circ Res. 1964 Jan;14:44–60. doi: 10.1161/01.res.14.1.44. [DOI] [PubMed] [Google Scholar]
  12. Hansen D. E., Craig C. S., Hondeghem L. M. Stretch-induced arrhythmias in the isolated canine ventricle. Evidence for the importance of mechanoelectrical feedback. Circulation. 1990 Mar;81(3):1094–1105. doi: 10.1161/01.cir.81.3.1094. [DOI] [PubMed] [Google Scholar]
  13. Kaufmann R. L., Bayer R. M., Harnasch C. Autoregulation of contractility in the myocardial cell. Displacement as a controlling parameter. Pflugers Arch. 1972;332(2):96–116. [PubMed] [Google Scholar]
  14. Lab M. J., Allen D. G., Orchard C. H. The effects of shortening on myoplasmic calcium concentration and on the action potential in mammalian ventricular muscle. Circ Res. 1984 Dec;55(6):825–829. doi: 10.1161/01.res.55.6.825. [DOI] [PubMed] [Google Scholar]
  15. Lab M. J. Contraction-excitation feedback in myocardium. Physiological basis and clinical relevance. Circ Res. 1982 Jun;50(6):757–766. doi: 10.1161/01.res.50.6.757. [DOI] [PubMed] [Google Scholar]
  16. Lab M. J. Transient depolarisation and action potential alterations following mechanical changes in isolated myocardium. Cardiovasc Res. 1980 Dec;14(11):624–637. doi: 10.1093/cvr/14.11.624. [DOI] [PubMed] [Google Scholar]
  17. Lab M. J., Woollard K. V. Monophasic action potentials, electrocardiograms and mechanical performance in normal and ischaemic epicardial segments of the pig ventricle in situ. Cardiovasc Res. 1978 Sep;12(9):555–565. doi: 10.1093/cvr/12.9.555. [DOI] [PubMed] [Google Scholar]
  18. Lazzara R., El-Sherif N., Hope R. R., Scherlag B. J. Ventricular arrhythmias and electrophysiological consequences of myocardial ischemia and infarction. Circ Res. 1978 Jun;42(6):740–749. doi: 10.1161/01.res.42.6.740. [DOI] [PubMed] [Google Scholar]
  19. Lerman B. B., Burkhoff D., Yue D. T., Franz M. R., Sagawa K. Mechanoelectrical feedback: independent role of preload and contractility in modulation of canine ventricular excitability. J Clin Invest. 1985 Nov;76(5):1843–1850. doi: 10.1172/JCI112177. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Levine J. H., Guarnieri T., Kadish A. H., White R. I., Calkins H., Kan J. S. Changes in myocardial repolarization in patients undergoing balloon valvuloplasty for congenital pulmonary stenosis: evidence for contraction-excitation feedback in humans. Circulation. 1988 Jan;77(1):70–77. doi: 10.1161/01.cir.77.1.70. [DOI] [PubMed] [Google Scholar]
  21. Loaldi A., Pepi M., Agostoni P. G., Fiorentini C., Grazi S., Della Bella P., Guazzi M. D. Cardiac rhythm in hypertension assessed through 24 hour ambulatory electrocardiographic monitoring. Effects of load manipulation with atenolol, verapamil, and nifedipine. Br Heart J. 1983 Aug;50(2):118–126. doi: 10.1136/hrt.50.2.118. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Macho P., Vatner S. F. Effects of nitroglycerin and nitroprusside on large and small coronary vessels in conscious dogs. Circulation. 1981 Dec;64(6):1101–1107. doi: 10.1161/01.cir.64.6.1101. [DOI] [PubMed] [Google Scholar]
  23. Mirro M. J., Bailey J. C., Watanabe A. M. Dissociation between the electrophysiological properties and total tissue cyclic guanosine monophosphate content of guinea pig atria. Circ Res. 1979 Aug;45(2):225–233. doi: 10.1161/01.res.45.2.225. [DOI] [PubMed] [Google Scholar]
  24. Mullins L. J. The generation of electric currents in cardiac fibers by Na/Ca exchange. Am J Physiol. 1979 Mar;236(3):C103–C110. doi: 10.1152/ajpcell.1979.236.3.C103. [DOI] [PubMed] [Google Scholar]
  25. Reiter M. J., Synhorst D. P., Mann D. E. Electrophysiological effects of acute ventricular dilatation in the isolated rabbit heart. Circ Res. 1988 Mar;62(3):554–562. doi: 10.1161/01.res.62.3.554. [DOI] [PubMed] [Google Scholar]
  26. Reuter H., Seitz N. The dependence of calcium efflux from cardiac muscle on temperature and external ion composition. J Physiol. 1968 Mar;195(2):451–470. doi: 10.1113/jphysiol.1968.sp008467. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Sideris D. A., Kontoyannis D. A., Michalis L., Adractas A., Moulopoulos S. D. Acute changes in blood pressure as a cause of cardiac arrhythmias. Eur Heart J. 1987 Jan;8(1):45–52. doi: 10.1093/oxfordjournals.eurheartj.a062158. [DOI] [PubMed] [Google Scholar]
  28. Tinker J. H., Michenfelder J. D. Sodium nitroprusside: pharmacology, toxicology and therapeutics. Anesthesiology. 1976 Sep;45(3):340–354. [PubMed] [Google Scholar]
  29. Webster M. W., Fitzpatrick M. A., Nicholls M. G., Ikram H., Wells J. E. Effect of enalapril on ventricular arrhythmias in congestive heart failure. Am J Cardiol. 1985 Sep 15;56(8):566–569. doi: 10.1016/0002-9149(85)91186-5. [DOI] [PubMed] [Google Scholar]

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