Mechanisms of Myocardial Ischemia in Hypertrophic Cardiomyopathy: Insights From Wave Intensity Analysis and Magnetic Resonance.

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Title: Mechanisms of Myocardial Ischemia in Hypertrophic Cardiomyopathy: Insights From Wave Intensity Analysis and Magnetic Resonance.
Authors: Raphael, CE
Cooper, R
Parker, KH
Collinson, J
Vassiliou, V
Pennell, DJ
De Silva, R
Hsu, LY
Greve, AM
Nijjer, S
Broyd, C
Ali, A
Keegan, J
Francis, DP
Davies, JE
Hughes, AD
Arai, A
Frenneaux, M
Stables, RH
Di Mario, C
Prasad, SK
Item Type: Journal Article
Abstract: BACKGROUND: Angina is common in hypertrophic cardiomyopathy (HCM) and is associated with abnormal myocardial perfusion. Wave intensity analysis improves the understanding of the mechanics of myocardial ischemia. OBJECTIVES: Wave intensity analysis was used to describe the mechanisms underlying perfusion abnormalities in patients with HCM. METHODS: Simultaneous pressure and flow were measured in the proximal left anterior descending artery in 33 patients with HCM and 20 control patients at rest and during hyperemia, allowing calculation of wave intensity. Patients also underwent quantitative first-pass perfusion cardiac magnetic resonance to measure myocardial perfusion reserve. RESULTS: Patients with HCM had a lower coronary flow reserve than control subjects (1.9 ± 0.8 vs. 2.7 ± 0.9; p = 0.01). Coronary hemodynamics in HCM were characterized by a very large backward compression wave during systole (38 ± 11% vs. 21 ± 6%; p < 0.001) and a proportionately smaller backward expansion wave (27% ± 8% vs. 33 ± 6%; p = 0.006) compared with control subjects. Patients with severe left ventricular outflow tract obstruction had a bisferiens pressure waveform resulting in an additional proximally originating deceleration wave during systole. The proportion of waves acting to accelerate coronary flow increased with hyperemia, and the magnitude of change was proportional to the myocardial perfusion reserve (rho = 0.53; p < 0.01). CONCLUSIONS: Coronary flow in patients with HCM is deranged. Distally, compressive deformation of intramyocardial blood vessels during systole results in an abnormally large backward compression wave, whereas proximally, severe left ventricular outflow tract obstruction is associated with an additional deceleration wave. Perfusion abnormalities in HCM are not simply a consequence of supply/demand mismatch or remodeling of the intramyocardial blood vessels; they represent a dynamic interaction with the mechanics of myocardial ischemia that may be amenable to treatment.
Issue Date: 11-Oct-2016
Date of Acceptance: 20-Jul-2016
URI: http://hdl.handle.net/10044/1/41578
DOI: https://dx.doi.org/10.1016/j.jacc.2016.07.751
ISSN: 1558-3597
Publisher: Elsevier
Start Page: 1651
End Page: 1660
Journal / Book Title: Journal of the American College of Cardiology
Volume: 68
Issue: 15
Copyright Statement: This article is available open access at https://dx.doi.org/10.1016/j.jacc.2016.07.751
Keywords: CMR
angina
cardiovascular magnetic resonance
left ventricular outflow tract obstruction
perfusion
CMR
angina
cardiovascular magnetic resonance
left ventricular outflow tract obstruction
perfusion
Cardiovascular System & Hematology
1102 Cardiovascular Medicine And Haematology
1117 Public Health And Health Services
Publication Status: Published
Appears in Collections:Faculty of Engineering
Bioengineering
National Heart and Lung Institute
Faculty of Medicine



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