A new electrocardiogram marker to identify patients at low risk for ventricular tachyarrhythmias: sum magnitude of the absolute QRST integral

Abstract

Objective-We proposed and tested a novel ECG marker of risk of ventricular arrhythmias (VA).Methods-Digital orthogonal ECGs were recorded at rest before ICD implantation in 508 participants of a primary prevention ICDs prospective cohort study (mean age 60±12; 377 male [74%]). The sum magnitude of the absolute QRST integral in 3 orthogonal leads (SAI QRST) was calculated. A derivation cohort of 128 patients was used to define a cutoff; a validation cohort (n=380) was used to test a predictive value.Results-During a mean follow-up of 18 months, 58 patients received appropriate ICD therapies. SAI QRST was lower in patients with VA (105.2±60.1 vs. 138.4±85.7 mV*ms, P=0.002). In the Cox proportional hazards analysis, patients with SAI QRST ≤145 mV*ms had about 4-fold higher risk of VA (HR3.6; 95% CI: 1.96-6.71, p<0.0001), and a 6-fold higher risk of monomorphic ventricular tachycardia [MMVT] (HR 6.58; P=0.014), whereas prediction of polymorphic ventricular tachycardia or ventricular fibrillation did not reach statistical significance.Conclusion-High SAI QRST is associated with low risk of sustained VA in patients with structural heart disease.Sudden cardiac death (SCD) strikes about 350,000 victims in the United States every year. 1 Implantable cardioverter-defibrillators (ICDs) are the treatment of choice2 -4 for patients at risk for SCD. The need to extend risk stratification beyond use of ejection fraction is well recognized.5 , 6 A U-shaped curve for ICD benefit was shown in the analysis of the MADIT II study, 5 prompting a search for markers that identify low-risk patients who do not benefit from ICD implantation. © 2010 Elsevier Inc. All rights reserved.Correspondence to Larisa G. Tereshchenko, MD, Carnegie 568, 600 N. Wolfe St., Baltimore, MD 21287. lteresh1@jhmi.edu Phone: 410-502-2796; Fax: 410-614-8039. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. During the century of electrocardiography multiple attempts were made to decipher complex information carried by cardiac electrical signal to obtain important clinical diagnostic and prognostic information. Several approaches have been proposed to develop composite ECG metrics that account for both amplitude and duration of ECG waveforms, with the goal to diagnose hypertrophy 7, 8, to determine localization and size of the scar9 -11, and to assess heterogeneity of action potential 12 . Although modern imaging modalities question utility of diagnostic ECG, prognostic ECG markers remain of interest. Arrhythmogenic substrate in susceptible to ventricular arrhythmia (VA) patients with structural heart disease is ...

Dynamic Changes in High Sensitivity Cardiac Troponin I are Associated with Dynamic Changes in Sum Absolute QRST Integral on Surface Electrocardiogram in Acute Decompensated Heart Failure

“…SAI QRST has been shown to be associated with ventricular arrhythmia, [5,6] SCD [4], appropriate ICD shocks [4][5][6], HF outcomes [4], and mechanical response on cardiac resynchronization therapy. [3] Our novel finding of the dynamic patient-specific association of SAI QRST with hsTnI in ADHF help to understand the mechanisms underlining acute changes in SAI QRST.…”

“…The absolute value of the area under the entire QRST waveform was measured on each orthogonal lead (X, Y, and Z). Absolute QRST integral values on X, Y, and Z leads were then summed to obtain SAI QRST as previously described [4][5][6]15].…”

Novel measure of electrical dyssynchrony predicts response in cardiac resynchronization therapy: Results from the SMART-AV Trial

“…Moreover, SAI QRST predicted sustained ventricular arrhythmias with appropriate ICD therapies 9–11 and cardiac death 11 in patients with and without conduction abnormalities. SAI QRST was developed as a simplified measure of action potential heterogeneity in the heart..…”

“…SAI QRST 9, 10 is a simple ECG marker of electrical remodeling and arrhythmia vulnerability, which in post-MI patients showed a correlation with the time passed since MI 11 . Moreover, SAI QRST predicted sustained ventricular arrhythmias with appropriate ICD therapies 9–11 and cardiac death 11 in patients with and without conduction abnormalities.…”

Genome‐Wide Associations of Global Electrical Heterogeneity ECG Phenotype: The ARIC (Atherosclerosis Risk in Communities) Study and CHS (Cardiovascular Health Study)

“…The sum absolute QRS‐T integral (SAI QRST) is a scalar analog of the SVG15, 16, 17, 18 which is associated with ventricular tachyarrhythmias in HF patients 15, 16, 19. SAI QRST is associated with electrical dyssynchrony,20 the mechanical response to cardiac resynchronization therapy (CRT),21 and mortality in patients with implanted CRT devices 22.…”