Use of T-wave alternans in identifying patients with coronary artery disease
Stefano Figliozzi1, Alessandra Stazi, Gaetano Pinnacchio
1Department of cardiovascular medicine, Università Cattolica del Sacro Cuore, Roma, Italy.
Insights
Microvolt T-wave alternans (MTWA) is elevated in patients with obstructive coronary artery disease (CAD). MTWA levels decrease after revascularization, aiding in the identification of CAD.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Microvolt T-wave alternans (MTWA) is a known predictor of fatal events in coronary artery disease (CAD) patients.
- Previous studies indicated higher MTWA in CAD patients compared to healthy individuals.
Purpose of the Study:
- To assess the relationship between coronary artery disease (CAD) and MTWA.
- To evaluate MTWA's diagnostic value in identifying obstructive CAD based on coronary angiography.
Main Methods:
- 98 patients undergoing coronary angiography for suspected CAD were studied.
- Maximal exercise stress tests (EST) and MTWA measurements were performed.
- Patients were categorized into groups based on stenosis severity and prior percutaneous coronary intervention (PCI).
Main Results:
- MTWA was significantly higher in patients with significant stenosis (58.7 ± 24 μV) compared to those without (34.2 ± 15 μV) or with prior PCI (43.2 ± 24 μV).
- An MTWA threshold of >60 μV demonstrated 95% specificity and 82% positive predictive value for obstructive CAD.
- MTWA decreased significantly post-PCI in treated patients, while remaining unchanged in controls.
Conclusions:
- MTWA is elevated in obstructive CAD and decreases following coronary revascularization.
- MTWA assessment can aid in identifying patients with obstructive CAD.
Aims:
Microvolt T-wave alternans (MTWA) has been found to predict fatal events in patients with coronary artery disease (CAD). In a previous study, we found that MTWA values are higher in patients with CAD, compared with apparently healthy individuals. In this study, we assessed the relation between CAD and MTWA in patients with a diagnosis based on coronary angiography results.
Methods:
We studied 98 consecutive patients undergoing coronary angiography for suspected CAD. All patients underwent a maximal exercise stress test (EST), and MTWA was measured in the precordial ECG leads. Patients were divided into three groups: 40 patients without any significant (>50%) stenosis (group 1); 47 patients with significant stenosis (group 2); and 11 patients with a previous percutaneous coronary intervention (PCI) who had no evidence of restenosis (group 3). EST was repeated after 1 month in 24 group 2 patients who underwent PCI and in 17 group 1 patients.
Results:
MTWA was significantly higher in group 2 (58.7 ± 24 μV) compared with group 1 (34.2 ± 15 μV, P < 0.01) and group 3 (43.2 ± 24 μV, P < 0.05). An MTWA greater than 60 μV had 95% specificity and 82% positive predictive value for obstructive CAD. At 1-month follow-up, MTWA decreased significantly in patients treated with PCI (from 61.3 ± 22 to 43.5 ± 17 μV; P < 0.001), but not in group 1 patients (from 50.5 ± 22 to 44.3 ± 19 μV, P = 0.19).
Conclusion:
MTWA is increased in patients with obstructive CAD and is reduced by coronary revascularization. An assessment of MTWA can be helpful in identifying which patients with suspected CAD are likely to show obstructive CAD on angiography.
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