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Article: Dynamic dyssynchrony and impaired contractile reserve of the left ventricle in beta-thalassaemia major: an exercise echocardiographic study
Title | Dynamic dyssynchrony and impaired contractile reserve of the left ventricle in beta-thalassaemia major: an exercise echocardiographic study |
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Authors | |
Keywords | Bicycle Cardiovascular magnetic resonance Cardiovascular parameters Controlled study Correlation analysis |
Issue Date | 2012 |
Publisher | Public Library of Science. The Journal's web site is located at http://www.plosone.org/home.action |
Citation | PLoS One, 2012, v. 7 n. 9, article no. e45265 How to Cite? |
Abstract | BACKGROUND: Performance of the left ventricle during exercise stress in thalassaemia patients is uncertain. We aimed to explore the phenomenon of dynamic dyssynchrony and assess contractile reserve in patients with beta-thalassaemia major and determine their relationships with myocardial iron load. METHODS AND RESULTS: Thirty-two thalassaemia patients (16 males), aged 26.8+/-6.9 years, without heart failure and 17 healthy controls were studied. Their left ventricular (LV) volumes, ejection fraction, systolic dyssynchrony index (SDI), and myocardial acceleration during isovolumic LV contraction (IVA) were determined at rest and during submaximal bicycle exercise testing using 3-dimensional and tissue Doppler echocardiography. Myocardial iron load as assessed by T2* cardiac magnetic resonance in patients were further related to indices of LV dyssynchrony and contractile reserve. At rest, patients had significantly greater LV SDI (p<0.001) but similar IVA (p = 0.22) compared with controls. With exercise stress, the prevalence of mechanical dyssynchrony (SDI>4.6%, control+2SD) increased from baseline 25% to 84% in patients. Delta SDI(exercise-baseline) correlated with exercise-baseline differences in LV ejection fraction (p<0.001) and stroke volume (p = 0.006). Compared with controls, patients had significantly less exercise-induced increase in LV ejection fraction, cardiac index, and IVA (interaction, all p<0.05) and had impaired contractile reserve as reflected by the gentler IVA-heart rate slope (p = 0.018). Cardiac T2* in patients correlated with baseline LV SDI (r = -0.44, p = 0.011) and IVA-heart rate slope (r = 0.36, p = 0.044). CONCLUSIONS: Resting LV dyssynchrony is associated with myocardial iron load. Exercise stress further unveils LV dynamic dyssynchrony and impaired contractile reserve in patients with beta-thalassaemia major. |
Persistent Identifier | http://hdl.handle.net/10722/169221 |
ISSN | 2023 Impact Factor: 2.9 2023 SCImago Journal Rankings: 0.839 |
PubMed Central ID | |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Cheung, YF | en_US |
dc.contributor.author | Yu, W | en_US |
dc.contributor.author | Li, SN | en_US |
dc.contributor.author | Lam, WWM | en_US |
dc.contributor.author | Ho, YC | en_US |
dc.contributor.author | Wong, SJ | en_US |
dc.contributor.author | Chan, GCF | en_US |
dc.contributor.author | Ha, SY | en_US |
dc.date.accessioned | 2012-10-18T08:46:00Z | - |
dc.date.available | 2012-10-18T08:46:00Z | - |
dc.date.issued | 2012 | en_US |
dc.identifier.citation | PLoS One, 2012, v. 7 n. 9, article no. e45265 | en_US |
dc.identifier.issn | 1932-6203 | - |
dc.identifier.uri | http://hdl.handle.net/10722/169221 | - |
dc.description.abstract | BACKGROUND: Performance of the left ventricle during exercise stress in thalassaemia patients is uncertain. We aimed to explore the phenomenon of dynamic dyssynchrony and assess contractile reserve in patients with beta-thalassaemia major and determine their relationships with myocardial iron load. METHODS AND RESULTS: Thirty-two thalassaemia patients (16 males), aged 26.8+/-6.9 years, without heart failure and 17 healthy controls were studied. Their left ventricular (LV) volumes, ejection fraction, systolic dyssynchrony index (SDI), and myocardial acceleration during isovolumic LV contraction (IVA) were determined at rest and during submaximal bicycle exercise testing using 3-dimensional and tissue Doppler echocardiography. Myocardial iron load as assessed by T2* cardiac magnetic resonance in patients were further related to indices of LV dyssynchrony and contractile reserve. At rest, patients had significantly greater LV SDI (p<0.001) but similar IVA (p = 0.22) compared with controls. With exercise stress, the prevalence of mechanical dyssynchrony (SDI>4.6%, control+2SD) increased from baseline 25% to 84% in patients. Delta SDI(exercise-baseline) correlated with exercise-baseline differences in LV ejection fraction (p<0.001) and stroke volume (p = 0.006). Compared with controls, patients had significantly less exercise-induced increase in LV ejection fraction, cardiac index, and IVA (interaction, all p<0.05) and had impaired contractile reserve as reflected by the gentler IVA-heart rate slope (p = 0.018). Cardiac T2* in patients correlated with baseline LV SDI (r = -0.44, p = 0.011) and IVA-heart rate slope (r = 0.36, p = 0.044). CONCLUSIONS: Resting LV dyssynchrony is associated with myocardial iron load. Exercise stress further unveils LV dynamic dyssynchrony and impaired contractile reserve in patients with beta-thalassaemia major. | - |
dc.language | eng | en_US |
dc.publisher | Public Library of Science. The Journal's web site is located at http://www.plosone.org/home.action | - |
dc.relation.ispartof | PLoS ONE | en_US |
dc.rights | This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. | - |
dc.subject | Bicycle | - |
dc.subject | Cardiovascular magnetic resonance | - |
dc.subject | Cardiovascular parameters | - |
dc.subject | Controlled study | - |
dc.subject | Correlation analysis | - |
dc.title | Dynamic dyssynchrony and impaired contractile reserve of the left ventricle in beta-thalassaemia major: an exercise echocardiographic study | en_US |
dc.type | Article | en_US |
dc.identifier.email | Cheung, YF: xfcheung@hku.hk | en_US |
dc.identifier.email | Wong, SJ: sjwong@hku.hk | en_US |
dc.identifier.email | Chan, GCF: gcfchan@hku.hk | en_US |
dc.identifier.email | Ha, SY: syha@hku.hk | en_US |
dc.identifier.authority | Cheung, YF=rp00382 | en_US |
dc.identifier.authority | Chan, GCF=rp00431 | en_US |
dc.description.nature | published_or_final_version | - |
dc.identifier.doi | 10.1371/journal.pone.0045265 | - |
dc.identifier.pmid | 23028894 | - |
dc.identifier.pmcid | PMC3445473 | - |
dc.identifier.scopus | eid_2-s2.0-84866481285 | - |
dc.identifier.hkuros | 212090 | en_US |
dc.identifier.volume | 7 | en_US |
dc.identifier.issue | 9, article no. e45265 | - |
dc.identifier.isi | WOS:000311313900109 | - |
dc.publisher.place | United States | - |
dc.identifier.issnl | 1932-6203 | - |