PMID- 2297830
OWN - NLM
STAT- MEDLINE
DCOM- 19900223
LR  - 20190623
IS  - 0009-7322 (Print)
IS  - 0009-7322 (Linking)
VI  - 81
IP  - 1
DP  - 1990 Jan
TI  - Assessment of left ventricular relaxation by Doppler echocardiography. Comparison 
      of isovolumic relaxation time and transmitral flow velocities with time constant 
      of isovolumic relaxation.
PG  - 260-6
AB  - Isovolumic relaxation time (IVRT) and events of early transmitral flow measured 
      by Doppler echocardiography were validated against the time constant of left 
      ventricular relaxation (tau) in open-chest dogs. During increased inotropy (by 
      isoproterenol infusion) at constant preload, enhancement of relaxation was 
      indicated by a decrease in tau from 48 +/- 12 (mean +/- SD) to 33 +/- 5 msec (p = 
      0.04) with a concomitant decrease in IVRT from 74 +/- 18 to 38 +/- 8 msec (p = 
      0.03). During decreased inotropy (by propranolol infusion) at constant preload, 
      slowing of relaxation was indicated by an increase in tau from 40 +/- 8 to 51 +/- 
      13 msec (p = 0.02) with a concomitant increase in IVRT from 71 +/- 15 to 83 +/- 
      21 msec (p less than 0.05). A significant correlation between changes in tau and 
      changes in IVRT was found (r = 0.66, p less than 0.001). In contrast, when left 
      ventricular end-diastolic pressure was increased from 7 +/- 2 to 24 +/- 4 mm Hg 
      at constant inotropy, tau increased from 47 +/- 14 to 64 +/- 25 msec (p = 0.03), 
      whereas no change in IVRT was observed (76 +/- 19 and 71 +/- 19 msec, 
      respectively). Aortic pressure was not significantly changed during any 
      intervention, and heart rate was kept constant by pacing. Peak early transmitral 
      velocity was unchanged by propranolol but increased during isoproterenol and 
      saline infusion (p less than 0.001 and p less than 0.01, respectively).(ABSTRACT 
      TRUNCATED AT 250 WORDS)
FAU - Myreng, Y
AU  - Myreng Y
AD  - Institute for Surgical Research, Rikshospitalet, University of Oslo, Norway.
FAU - Smiseth, O A
AU  - Smiseth OA
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Circulation
JT  - Circulation
JID - 0147763
SB  - IM
MH  - Animals
MH  - Blood Flow Velocity
MH  - Dogs
MH  - *Echocardiography, Doppler
MH  - Mitral Valve/*physiology
MH  - *Models, Cardiovascular
MH  - *Myocardial Contraction
MH  - Reproducibility of Results
MH  - Time Factors
EDAT- 1990/01/01 00:00
MHDA- 1990/01/01 00:01
CRDT- 1990/01/01 00:00
PHST- 1990/01/01 00:00 [pubmed]
PHST- 1990/01/01 00:01 [medline]
PHST- 1990/01/01 00:00 [entrez]
AID - 10.1161/01.cir.81.1.260 [doi]
PST - ppublish
SO  - Circulation. 1990 Jan;81(1):260-6. doi: 10.1161/01.cir.81.1.260.