New insight into scar-related ventricular tachycardia circuits in ischemic cardiomyopathy: Fat deposition after myocardial infarction on computed tomography - A pilot study

Takeshi Sasaki, Hugh Calkins, Christopher F. Miller, Menekhem M. Zviman, Vadim Zipunnikov, Tomio Arai, Motoji Sawabe, Masashiro Terashima, Joseph E. Marine, Ronald D. Berger, Saman Nazarian, Stefan L. Zimmerman

Research output: Contribution to journalArticle

Abstract

Background Myocardial fat deposition (FAT-DEP) has been frequently observed in regions of chronic myocardial infarction in patients with ischemic cardiomyopathy. The role of FAT-DEP within scar-related ventricular tachycardia (VT) circuits has not been investigated. Objective This pilot study aimed to assess the impact of myocardial FAT-DEP on local electrograms and VT circuits in patients with ischemic cardiomyopathy. Methods Contrast-enhanced computed tomography was performed in 22 patients with ischemic VT. Electroanatomic map points were registered to the corresponding contrast-enhanced computed tomography images. Myocardial FAT-DEP was identified and characterized using a postprocessing image overlay that highlighted areas below 0 Hounsfield units (HU). The mean attenuation of local myocardial regions corresponding to sampled electrograms was measured on short-axis images. The associations of mean attenuation with bipolar and unipolar amplitudes, left ventricular wall thickness, and VT circuit sites were investigated. Results Of 1801 electroanatomic map points, 519 (28.8%) were located in regions with FAT-DEP. Significant differences were observed in mean intensity (23.2 ± 35.6 HU vs 81.7 ± 21.9 HU; P <.001), bipolar (0.75 ± 0.83 mV vs 2.9 ± 2.4 mV; P <.001) and unipolar (3.1 ± 1.7 mV vs 7.4 ± 4.3 mV; P <.001) amplitudes, and left ventricular wall thickness (5.2 ± 1.7 mm vs 8.2 ± 2.5 mm; P <.001) between regions with and without FAT-DEP. Lower HU was strongly associated with lower bipolar and unipolar amplitudes (P <.0001, respectively). Importantly, FAT-DEP was associated with critical VT circuit sites with fractionated or isolated potentials. Conclusion FAT-DEP was associated with electrogram characteristics and VT circuit sites. Further work will be needed to determine whether FAT-DEP plays a causal role in the generation of ischemic scar-related VT circuits.

Original languageEnglish (US)
Pages (from-to)1508-1518
Number of pages11
JournalHeart Rhythm
Volume12
Issue number7
DOIs
StatePublished - Jul 1 2015

Keywords

  • Computed tomography
  • Fat
  • Ischemic cardiomyopathy
  • Magnetic resonance imaging
  • Ventricular tachycardia

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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