High-frequency QRS electrocardiogram analysis during exercise stress testing for detecting ischemia.


Journal Article

INTRODUCTION: ECG stress testing is an inexpensive and non-invasive detector of myocardial ischemia; addition of high-frequency QRS analysis (HFQRS) may improve accuracy. This study compared HFQRS during exercise in patients with and without ischemia as defined by multiple criteria. MATERIAL AND METHODS: High-resolution ECGs were recorded for 139 patients undergoing T99-sestamibi/T201-thallium stress testing. Twenty-three were positive by at least two and 37 were negative for ischemia by all three of the following criteria: nuclear scan, ST-segment analysis and typical angina. Sixty-four not meeting criteria for positive or negative, six with adenosine test and nine patients with ECG recording artifacts were excluded. Mean age of the study group was 62+/-10 years, 83% were male. Ischemic patients had a higher incidence of previous myocardial infarction and coronary intervention than non-ischemic patients (74% vs. 46%; P=0.03 and 70% vs. 43%; P=0.05, respectively), but had a lower body mass index (28.7+/-5 vs. 33.0+/-8; P=0.015). HFQRS analysis consisting of signal averaging (150-250 Hz) and calculation of root mean squared values for each lead at different time points was performed and was similar between the groups. The relative change in HFQRS (RCQ) was calculated for each lead: {(maxHFQRS-minHFQRS)/maxHFQRS}. For each patient an RCQ index was calculated by averaging the two leads with the greatest RCQ value. The RCQ index was greater in ischemic vs. non-ischemic patients (45% vs. 34%; P=0.0069). CONCLUSION: Maximum decrease in HFQRS, as quantified by RCQ index, was greater in ischemic vs. non-ischemic patients. Use of the RCQ index may improve the diagnosis of ischemia during exercise stress testing.

Full Text

Cited Authors

  • Lipton, JA; Warren, SG; Broce, M; Abboud, S; Beker, A; Sörnmo, L; Lilly, DR; Maynard, C; Lucas, BD; Wagner, GS

Published Date

  • February 2008

Published In

Volume / Issue

  • 124 / 2

Start / End Page

  • 198 - 203

PubMed ID

  • 17462756

Pubmed Central ID

  • 17462756

Electronic International Standard Serial Number (EISSN)

  • 1874-1754

International Standard Serial Number (ISSN)

  • 0167-5273

Digital Object Identifier (DOI)

  • 10.1016/j.ijcard.2007.02.002


  • eng