|
1
|
Abd-Elmoniem KZ, Tomas MS, Sasano T, Soleimanifard S, Vonken EJP, Youssef A, Agarwal H, Dimaano VL, Calkins H, Stuber M, Prince JL, Abraham TP, Abraham MR. Assessment of distribution and evolution of mechanical dyssynchrony in a porcine model of myocardial infarction by cardiovascular magnetic resonance. J Cardiovasc Magn Reson 2012; 14:1. [PMID: 22226320 PMCID: PMC3268109 DOI: 10.1186/1532-429x-14-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 01/06/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND We sought to investigate the relationship between infarct and dyssynchrony post- myocardial infarct (MI), in a porcine model. Mechanical dyssynchrony post-MI is associated with left ventricular (LV) remodeling and increased mortality. METHODS Cine, gadolinium-contrast, and tagged cardiovascular magnetic resonance (CMR) were performed pre-MI, 9 ± 2 days (early post-MI), and 33 ± 10 days (late post-MI) post-MI in 6 pigs to characterize cardiac morphology, location and extent of MI, and regional mechanics. LV mechanics were assessed by circumferential strain (eC). Electro-anatomic mapping (EAM) was performed within 24 hrs of CMR and prior to sacrifice. RESULTS Mean infarct size was 21 ± 4% of LV volume with evidence of post-MI remodeling. Global eC significantly decreased post MI (-27 ± 1.6% vs. -18 ± 2.5% (early) and -17 ± 2.7% (late), p < 0.0001) with no significant change in peri-MI and MI segments between early and late time-points. Time to peak strain (TTP) was significantly longer in MI, compared to normal and peri-MI segments, both early (440 ± 40 ms vs. 329 ± 40 ms and 332 ± 36 ms, respectively; p = 0.0002) and late post-MI (442 ± 63 ms vs. 321 ± 40 ms and 355 ± 61 ms, respectively; p = 0.012). The standard deviation of TTP in 16 segments (SD16) significantly increased post-MI: 28 ± 7 ms to 50 ± 10 ms (early, p = 0.012) to 54 ± 19 ms (late, p = 0.004), with no change between early and late post-MI time-points (p = 0.56). TTP was not related to reduction of segmental contractility. EAM revealed late electrical activation and greatly diminished conduction velocity in the infarct (5.7 ± 2.4 cm/s), when compared to peri-infarct (18.7 ± 10.3 cm/s) and remote myocardium (39 ± 20.5 cm/s). CONCLUSIONS Mechanical dyssynchrony occurs early after MI and is the result of delayed electrical and mechanical activation in the infarct.
Collapse
Affiliation(s)
- Khaled Z Abd-Elmoniem
- Biomedical and Metabolic Imaging Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
| | - Miguel Santaularia Tomas
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
- Department of Medicine, Division of Cardiology, Hospital Español de Mexico, Distrito Federal, Mexico
| | - Tetsuo Sasano
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Sahar Soleimanifard
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Evert-Jan P Vonken
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Amr Youssef
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Harsh Agarwal
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Veronica L Dimaano
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Hugh Calkins
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - Matthias Stuber
- Department of Radiology, Division of Magnetic Resonance Research, Johns Hopkins University, Baltimore, MD, USA
| | - Jerry L Prince
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Theodore P Abraham
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| | - M Roselle Abraham
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|