TY - JOUR
T1 - Wall thickness referenced to myocardial volume
T2 - A new noninvasive framework for cardiac mechanics
AU - Denslow, Stewart
AU - Balaji, Seshadri
AU - Hewett, Kenneth W.
PY - 1999/7
Y1 - 1999/7
N2 - Dimensional variables measured for study of left ventricular mechanics are subject to errors arising from difficulty in determining zero-stress dimensions for use as a reference. Based on a method validated for measurements within individuals, we have devised an approach that facilitates comparison between individuals while minimizing random scatter. We define an exact mathematical index of strain, ln(h0/h), using wall thickness (h) referenced to extrapolated wall thickness at zero-luminal volume (h0). Noninvasive data from rabbits, pigs, and humans all yielded highly similar myocardial stress, ln(h0/h), and work values. The stress-ln(h0/h) relationship during afterload variation was constant among individual pigs with a twofold variation in ventricular mass. Stress-ln(h0/h) data from our analysis displayed lower scatter than either pressure-volume data normalized to myocardial mass or stress-ln(h0/h) data referenced to end-diastolic dimensions. A Frank-Starling-like curve with high correlation (r2 = 0.96) was constructed from single points from different pigs, suggesting a low level of size and intersubject scatter. This method offers high precision for noninvasive characterization of ventricular and myocardial mechanics and for comparisons between subjects and between species.
AB - Dimensional variables measured for study of left ventricular mechanics are subject to errors arising from difficulty in determining zero-stress dimensions for use as a reference. Based on a method validated for measurements within individuals, we have devised an approach that facilitates comparison between individuals while minimizing random scatter. We define an exact mathematical index of strain, ln(h0/h), using wall thickness (h) referenced to extrapolated wall thickness at zero-luminal volume (h0). Noninvasive data from rabbits, pigs, and humans all yielded highly similar myocardial stress, ln(h0/h), and work values. The stress-ln(h0/h) relationship during afterload variation was constant among individual pigs with a twofold variation in ventricular mass. Stress-ln(h0/h) data from our analysis displayed lower scatter than either pressure-volume data normalized to myocardial mass or stress-ln(h0/h) data referenced to end-diastolic dimensions. A Frank-Starling-like curve with high correlation (r2 = 0.96) was constructed from single points from different pigs, suggesting a low level of size and intersubject scatter. This method offers high precision for noninvasive characterization of ventricular and myocardial mechanics and for comparisons between subjects and between species.
KW - Ventricular function
KW - Ventricular geometry
KW - Wall stress
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U2 - 10.1152/jappl.1999.87.1.211
DO - 10.1152/jappl.1999.87.1.211
M3 - Article
C2 - 10409577
AN - SCOPUS:0032798806
SN - 8750-7587
VL - 87
SP - 211
EP - 221
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 1
ER -