How inotropic drugs alter dynamic and static indices of cyclic myoplasmic [Ca2+] to contractility relationships in intact hearts. J Cardiovasc Pharmacol 2003 Oct;42(4):539-53
Date
09/26/2003Pubmed ID
14508241DOI
10.1097/00005344-200310000-00013Scopus ID
2-s2.0-0141642005 (requires institutional sign-in at Scopus site) 14 CitationsAbstract
The authors examined effects of positive (dopamine and digoxin) and negative (nifedipine and lidocaine) inotropic interventions on the instantaneous cyclic relationship between myoplasmic [Ca2+] and simultaneously developed left ventricular pressure (LVP) in intact guinea pig hearts. Novel indices were developed to quantify this relationship based on (1) transient [Ca2+] and LVP signal morphology, ie, maxima and minima, peak derivatives, beat areas, durations, and ratios of indices of LVP to [Ca2+]; (2) temporal delay; and (3) LVP versus [Ca2+] loop morphology, ie, orientation, size, hysteresis, position, shape, and duration. These analyses were used to assess the cost of phasic [Ca2+] for contraction and relaxation over one beat after inotropic intervention. It was found that dopamine and digoxin increased contractile and relaxation responsiveness to phasic [Ca2+], cumulative Ca2+, and net Ca2+ flux. Unlike dopamine, digoxin did not decrease relaxation response time. Nifedipine and lidocaine decreased contractile and relaxation responsiveness to phasic [Ca2+], cumulative Ca2+, and net Ca2+ flux. Unlike lidocaine, nifedipine decreased net available Ca2+ and Ca2+ influx. Positive inotropic agents increased [Ca2+]-LVP loop area and hysteresis and resulted in a more vertically oriented loop. Nifedipine and lidocaine decreased these loop indices and lidocaine exhibited greater loop hysteresis than did nifedipine. These novel indices provide a quantitative assessment of myoplasmic [Ca2+] handling for cardiac contractile function.
Author List
Rhodes SS, Ropella KM, Camara AK, Chen Q, Riess ML, Stowe DFAuthors
Amadou K. Camara PhD Professor in the Anesthesiology department at Medical College of WisconsinDavid F. Stowe MD, PhD Professor in the Anesthesiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsCalcium
Digoxin
Dopamine
Guinea Pigs
Lidocaine
Muscle Contraction
Myocardial Contraction
Myocardium
Nifedipine
Signal Processing, Computer-Assisted
Ventricular Function
Ventricular Function, Left
Ventricular Pressure
