PMID- 8655470
OWN - NLM
STAT- MEDLINE
DCOM- 19960731
LR  - 20191101
IS  - 0910-8327 (Print)
IS  - 0910-8327 (Linking)
VI  - 10
IP  - 6
DP  - 1995
TI  - Percutaneous transvenous mitral commissurotomy immediately restores quick 
      response of VO2 to mild exercise despite insignificant increases in peak VO2.
PG  - 323-7
AB  - Percutaneous transvenous mitral commissurotomy (PTMC) increases peak oxygen 
      uptake (VO2) chronically, but not acutely, despite early symptomatic 
      improvements. Analysis of transient VO2 responses to submaximal exercise (an 
      exercise regimen more comparable to the patients' daily activities than that 
      provided by maximal exercise testing), may be sensitive in detecting the acute 
      hemodynamic benefits of PTMC. Since no methods are available to accurately 
      estimate the transient response of VO2, we developed a new technique, using 
      random exercise. In 15 patients who underwent successful PTMC, we repeated the 
      conventional maximal exercise test and the random exercise test before and within 
      a few days after PTMC. For the random exercise test, we intermittently imposed 
      upright bicycle exercise at 50 W, according to a random binary sequence, while 
      measuring breath-by-breath VO2. After determining the transfer function relating 
      workload to VO2, we computed the high resolution VO2 response to a hypothetical 
      step increase in exercise. Despite improvements in resting hemodynamics and New 
      York Heart Association (NYHA) Class, peak VO2 improved insignificantly (952 +/- 
      271 vs 1,029 +/- 342 ml/min, P = 0.063) shortly after successful PTMC. In 
      contrast, the amplitude of the VO2 step response increased significantly in the 
      early-to-mid portion (28-76s; P < 0.01-0.05). The remaining portion was 
      unchanged. Consequently, the time constant shortened from 64 +/- 26 to 48 +/- 22s 
      (P < 0.05). The maximal Borg scale value during random exercise decreased 
      significantly (13.1 +/- 1.8 vs 11.4 +/- 1.1; P < 0.01). We conclude that the VO2 
      step response, using the random exercise test, is more sensitive than peak VO2 in 
      detecting the functional improvement that is coupled with the hemodynamic 
      improvement immediately after PTMC.
FAU - Takaki, H
AU  - Takaki H
AD  - Department of Cardiovascular Dynamics, National Cardiovascular Center Research 
      Institute, Osaka, Japan.
FAU - Sunagawa, K
AU  - Sunagawa K
FAU - Sugimachi, M
AU  - Sugimachi M
FAU - Tamai, J
AU  - Tamai J
FAU - Okano, Y
AU  - Okano Y
FAU - Kurita, T
AU  - Kurita T
FAU - Aihara, N
AU  - Aihara N
FAU - Shimizu, W
AU  - Shimizu W
FAU - Suyama, K
AU  - Suyama K
FAU - Kamakura, S
AU  - Kamakura S
AU  - et al.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - Japan
TA  - Heart Vessels
JT  - Heart and vessels
JID - 8511258
SB  - IM
MH  - Adult
MH  - *Catheterization/methods
MH  - Exercise/physiology
MH  - Exercise Test
MH  - Female
MH  - Hemodynamics/physiology
MH  - Humans
MH  - Linear Models
MH  - Male
MH  - Middle Aged
MH  - Mitral Valve Stenosis/physiopathology/*therapy
MH  - *Oxygen Consumption/physiology
MH  - Prognosis
EDAT- 1995/01/01 00:00
MHDA- 1995/01/01 00:01
CRDT- 1995/01/01 00:00
PHST- 1995/01/01 00:00 [pubmed]
PHST- 1995/01/01 00:01 [medline]
PHST- 1995/01/01 00:00 [entrez]
AID - 10.1007/BF02911391 [doi]
PST - ppublish
SO  - Heart Vessels. 1995;10(6):323-7. doi: 10.1007/BF02911391.