TY - JOUR
T1 - Ventricular relaxation and myocardial ischemia
T2 - A comparison of different models of tau during coronary angioplasty
AU - Simari, Robert D.
AU - Bell, Malcolm R.
AU - Schwartz, Robert S.
AU - Nishimura, Rick A.
AU - Holmes, David R.
PY - 1992/4
Y1 - 1992/4
N2 - This study compares the sensitivity and variability of four models of tau, the time constant of ventricular relaxation, to detect the presence of myocardial ischemia. High fidelity left ventricular pressure recordings were obtained in ten patients undergoing coronary angioplasty at baseline, during balloon inflation, and at recovery. Four models of tau were considered: (1) a semilogarithmic, zero asymptote model (TL), (2) a semilogarithmic model using data from the first 40 ms of isovolumic relaxation (T40), (3) an exponential non‐zero asymptote model (Te), and (4) a derivative non‐zero asymptote model (TD). TL, T40, and TE increased significantly during inflation and returned to near baseline values at recovery. TD showed no change during inflation. Comparisons of TL, T40, and TE using the derived relaxation half‐time (T1/2), failed to reveal significant differences between the models at baseline, during inflation, or at recovery. The non‐zero asymptote models were associated with a greater beat‐to‐beat variability than the semilogarithmic models. Thus, T1/2 using the semilogarithmic zero asymptote models (TL and T40) may be more useful and consistent when measuring the rate of isovolumic relaxation during myocardial ischemia.
AB - This study compares the sensitivity and variability of four models of tau, the time constant of ventricular relaxation, to detect the presence of myocardial ischemia. High fidelity left ventricular pressure recordings were obtained in ten patients undergoing coronary angioplasty at baseline, during balloon inflation, and at recovery. Four models of tau were considered: (1) a semilogarithmic, zero asymptote model (TL), (2) a semilogarithmic model using data from the first 40 ms of isovolumic relaxation (T40), (3) an exponential non‐zero asymptote model (Te), and (4) a derivative non‐zero asymptote model (TD). TL, T40, and TE increased significantly during inflation and returned to near baseline values at recovery. TD showed no change during inflation. Comparisons of TL, T40, and TE using the derived relaxation half‐time (T1/2), failed to reveal significant differences between the models at baseline, during inflation, or at recovery. The non‐zero asymptote models were associated with a greater beat‐to‐beat variability than the semilogarithmic models. Thus, T1/2 using the semilogarithmic zero asymptote models (TL and T40) may be more useful and consistent when measuring the rate of isovolumic relaxation during myocardial ischemia.
KW - diastole
KW - myocardial function
KW - myocardial relaxation
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U2 - 10.1002/ccd.1810250404
DO - 10.1002/ccd.1810250404
M3 - Article
C2 - 1571988
AN - SCOPUS:0026530202
SN - 0098-6569
VL - 25
SP - 278
EP - 284
JO - Catheterization and cardiovascular diagnosis
JF - Catheterization and cardiovascular diagnosis
IS - 4
ER -