Abstract
Background: Little is known about the prevalence and prognostic significance of long QT interval among patients with chest pain during the acute phase of suspected cardiovascular injury.
Objectives: Our aim was to investigate the prevalence and prognostic significance of long QT interval among patients presenting to the emergency department (ED) with chest pain using an optimum QT rate correction formula.
Methods: We performed secondary analysis on data obtained from the IMMEDIATE AIM trial (N, 145). Data included 24-hour 12-lead Holter electrocardiographic recordings that were stored for offline computer analysis. The QT interval was measured automatically and rate corrected using seven QTc formulas including subject specific correction. The formula with the closer to zero absolute mean QTc/RR correlation was considered the most accurate.
Results: Linear and logarithmic subject specific QT rate correction outperformed other QTc formulas and resulted in the closest to zero absolute mean QTc/RR correlations (mean ± SD: 0.003 ± 0.002 and 0.017 ± 0.016, respectively). These two formulas produced adequate correction in 100% of study participants. Other formulas (Bazett’s, Fridericia’s, Framingham's, and study specific) resulted in inadequate correction in 47.6 to 95.2% of study participants. Using the optimum QTc formula, linear subject specific, the prevalence of long QTc interval was 14.5%. The QTc interval did not predict mortality or hospital admission at short and long term follow-up. Only the QT/RR slope predicted mortality at 7 year follow-up (odds ratio, 2.01; 95% CI, 1.02–3.96; p < 0.05). Conclusions: Adequate QT rate correction can only be performed using subject specific correction. Long QT interval is not uncommon among patients presenting to the ED with chest pain.
| Original language | American English |
|---|---|
| Pages (from-to) | 336-342 |
| Number of pages | 7 |
| Journal | Journal of Electrocardiology |
| Volume | 46 |
| Issue number | 4 |
| State | Published - Jul 1 2013 |
Funding
This was a secondary analysis of data obtained from the Ischemia Monitoring and Management in the Emergency Department in Analysis and Treatment of Acute Ischemic Myocardium (IMMEDIATE AIM) trial funded by the National Institutes of Health (RO1HL69753). 11 Data included 24-hour 12-lead Holter with high resolution ECG acquisition signal (1000 sample/second/channel) (N, 187). Excluded from the present analysis were patients with right (n, 16) or left (n, 10) bundle branch block, atrial fibrillation (n, 8), atrial flutter (n, 1), artificial pacemakers (n, 3), or a combination of these conditions (n, 4). The total sample size for the final analysis was 145.
| Funders | Funder number |
|---|---|
| National Institutes of Health | |
| National Heart, Lung, and Blood Institute | R01HL069753 |
Keywords
- Artifacts
- Chest Pain/diagnosis
- Comorbidity
- Diagnosis, Computer-Assisted/methods
- Electrocardiography, Ambulatory/statistics & numerical data
- Female
- Heart Rate
- Humans
- Long QT Syndrome/diagnosis
- Male
- Middle Aged
- Prevalence
- Prognosis
- Reproducibility of Results
- Risk Factors
- Sensitivity and Specificity
- Survival Analysis
- United States
Disciplines
- Nursing