TY - JOUR
T1 - Alterations in left ventricular torsion in tachycardia-induced dilated cardiomyopathy
AU - Tibayan, Frederick A.
AU - Lai, David T.M.
AU - Timek, Tomasz A.
AU - Dagum, Paul
AU - Liang, David
AU - Daughters, George T.
AU - Ingels, Neil B.
AU - Miller, D. Craig
N1 - Funding Information:
Supported by grants HL-29589 and HL-67025 from the National Heart, Lung, and Blood Institute. Drs Tibayan, Lai, Timek, and Dagum are Carl and Leah McConnell Cardiovascular Surgical Research Fellows. Dr Timek is a recipient of the Thoracic Surgery Foundation Research Fellowship. Drs. Timek, Dagum, and Tibayan were supported by NHLBI Individual Research Service Awards HL-10452, HL-09569, and HL-67563, respectively. Dr Lai was supported by a fellowship from the American Heart Association, Western States Affiliate.
PY - 2002/7/1
Y1 - 2002/7/1
N2 - Objective: Left ventricular torsion reduces transmural systolic gradients of fiber strain, and torsional recoil in early diastole is thought to enhance left ventricular filling. Left ventricular remodeling in dilated cardiomyopathy may result in changes in torsion dynamics, but these effects are not yet characterized. Tachycardia-induced cardiomyopathy is accompanied by systolic and diastolic heart failure and left ventricular remodeling. We hypothesized that cardiomyopathy would alter systolic and diastolic left ventricular torsion mechanics, and this hypothesis was tested by studying sheep before and after the development of tachycardia-induced cardiomyopathy. Methods: Implanted miniature radiopaque markers were used in 8 sheep to measure left ventricular geometry and function, maximal torsional deformation, and early diastolic recoil before and after rapid ventricular pacing was used to create tachycardia-induced cardiomyopathy. Results: All animals had significant heart failure with ventricular dilatation and remodeling. With tachycardia-induced cardiomyopathy, maximum torsion relative to control conditions decreased (1.69° ± 0.61° vs 4.25° ± 2.33°), and early diastolic recoil was completely abolished (0.53° ± 1.19° vs -1.17° ± 0.94°). Conclusions: Cardiomyopathy is accompanied by decreased and delayed systolic left ventricular torsional deformation and loss of early diastolic recoil, which may contribute to left ventricular dysfunction by increasing systolic transmural strain gradients and impairing diastolic filling. Analysis of left ventricular torsion with radiofrequency-tagging magnetic resonance imaging should be explored to elucidate the role of torsion in patients with cardiomyopathy.
AB - Objective: Left ventricular torsion reduces transmural systolic gradients of fiber strain, and torsional recoil in early diastole is thought to enhance left ventricular filling. Left ventricular remodeling in dilated cardiomyopathy may result in changes in torsion dynamics, but these effects are not yet characterized. Tachycardia-induced cardiomyopathy is accompanied by systolic and diastolic heart failure and left ventricular remodeling. We hypothesized that cardiomyopathy would alter systolic and diastolic left ventricular torsion mechanics, and this hypothesis was tested by studying sheep before and after the development of tachycardia-induced cardiomyopathy. Methods: Implanted miniature radiopaque markers were used in 8 sheep to measure left ventricular geometry and function, maximal torsional deformation, and early diastolic recoil before and after rapid ventricular pacing was used to create tachycardia-induced cardiomyopathy. Results: All animals had significant heart failure with ventricular dilatation and remodeling. With tachycardia-induced cardiomyopathy, maximum torsion relative to control conditions decreased (1.69° ± 0.61° vs 4.25° ± 2.33°), and early diastolic recoil was completely abolished (0.53° ± 1.19° vs -1.17° ± 0.94°). Conclusions: Cardiomyopathy is accompanied by decreased and delayed systolic left ventricular torsional deformation and loss of early diastolic recoil, which may contribute to left ventricular dysfunction by increasing systolic transmural strain gradients and impairing diastolic filling. Analysis of left ventricular torsion with radiofrequency-tagging magnetic resonance imaging should be explored to elucidate the role of torsion in patients with cardiomyopathy.
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U2 - 10.1067/mtc.2002.121299
DO - 10.1067/mtc.2002.121299
M3 - Article
C2 - 12091807
AN - SCOPUS:0036657894
SN - 0022-5223
VL - 124
SP - 43
EP - 49
JO - Journal of Thoracic and Cardiovascular Surgery
JF - Journal of Thoracic and Cardiovascular Surgery
IS - 1
ER -