T-wave alternans and ST depression assessment identifies low risk individuals with ischemic cardiomyopathy in the absence of left ventricular hypertrophy

Baroreflex sensitivity but not microvolt T-wave alternans can predict major adverse cardiac events in ischemic heart failure

BACKGROUND

Major adverse cardiovascular events (MACE) constitutes the main cause of morbidity and mortality in ischemic heart failure (HF) patients. The prognostic value of the autonomic nervous system parameters and microvolt T-wave alternans (MTWA) in this issue has not been identified to date. The aim herein, was to assess the usefulness of the abovementioned parameters in the prediction of MACE in HF patients with left ventricular systolic dysfunction of ischemic origin.

METHODS

Baroreflex sensitivity (BRS), heart rate variability (HRV), MTWA and other well-known clinical parameters were analyzed in 188 ischemic HF outpatients with left ventricular ejection fraction (LVEF) ≤ 50%. During 34 (14-71) months of follow-up, 56 (30%) endpoints were noted.

RESULTS

Univariate Cox analyses revealed BRS (but not HRV), MTWA, age, New York Heart Association functional class III, LVEF, implantable cardioverter-defibrillator presence, use of diuretics and antiarrhythmic drugs, diabetes, and kidney insufficiency were defined as significant predictors of MACE. Pre-specified cut-off values for MACE occurrence for the aforementioned continuous parameters (age, LVEF, and BRS) were: ≥ 72 years, ≤ 33%, and ≤ 3 ms/mmHg, respectively. In a multivariate Cox analysis only BRS (HR 2.97, 95% CI 1.35-6.36, p < 0.006), and LVEF (HR 1.98, 95% CI 0.61-4.52, p < 0.038) maintained statistical significance in the prediction of MACE.

CONCLUSIONS

Baroreflex sensitivity and LVEF are independent of other well-known clinical parameters in the prediction of MACE in patients with HF of ischemic origin and LVEF up to 50%. BRS ≤ 3 ms/mmHg and LVEF ≤ 33% identified individuals with the highest probability of MACE during the follow-up period.

Microvolt T-wave alternans in young myocardial infarction patients with preserved cardiac function treated with single-vessel primary percutaneous coronary intervention

Introduction

Myocardial infarction continues to be the most important cause of morbidity and mortality, and recently this disease has begun to be seen commonly at young ages. In our study we aimed to assess microvolt T-wave alternans in young patients who had ST segment elevation myocardial infarction with preserved left ventricular function and who underwent single-vessel revascularization.

Material and methods

We enrolled 108 consecutive patients (age: 39.5 ±4.1) with ST segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention and 43 patients (age: 38.5 ±3.7) with normal coronary angiograms as a control group. The myocardial infarction patients were younger than 45 and had a preserved left ventricular ejection fraction. They were divided into three groups according to the culprit artery. The microvolt T-wave alternans (MTWA) values were calculated an average of 12 months after the primary percutaneous coronary intervention using the modified moving average method.

Results

The MTWA positivity was significantly higher in the STEMI group compared to the controls (p < 0.001). It was also significantly higher in STEMI patients with left anterior descending artery lesions compared to patients with circumflex artery and right coronary artery lesions (p = 0.013). Moreover, the culprit artery was independent predictor of MTWA positivity (p = 0.043).

Conclusions

In STEMI patients of a young age, MTWA positivity was higher than in healthy individuals, especially when the responsible vessel fed a wider region.

Ischemic Electrocardiographic Abnormalities and Prognosis in Decompensated Heart Failure

Background—

Identification of coronary ischemia may enable targeted diagnostic and therapeutic strategies for acute heart failure. We determined the risk of 30-day mortality associated with ischemic ECG abnormalities in patients with acute heart failure.

Methods and Results—

Among 8772 patients (53.4% women, median 78 years [Q1, Q3: 68,84]) presenting with acute heart failure to 86 hospital emergency departments in Ontario, Canada, Q-waves, T-wave inversion, or ST-depression were present in 51.8% of subjects. However, presence of ST-depression was the only finding associated with 30-day mortality with adjusted odds ratio 1.24 (95% confidence interval [CI], 1.02–1.50). Using continuous net reclassification improvement, addition of ST-depression to the Emergency Heart failure Mortality Risk Grade model reclassified 16.9% of patients overall, and 29.3% of those with a history of ischemic heart disease (both P <0.001). By adding ST-depression to the model, the Emergency Heart failure Mortality Risk Grade was extended to predict 30-day death with high discrimination ( c -statistic 0.801), with 0.57% mortality rate in the lowest risk decile. Adjusted odds ratios for 30-day mortality were 2.81 (95% CI, 1.48–5.31; P =0.002) in quintile 2, 7.41 (95% CI, 4.13–13.30; P <0.001) in quintile 3, and 14.47 (95% CI, 8.20–25.54; P <0.001) in quintile 4 compared with the lowest risk quintile. When the highest risk quintile was subdivided into 2 equally sized risk strata (deciles 9 and 10), the adjusted odds ratios for 30-day mortality were 27.20 (95% CI, 15.33–48.27; P <0.001) in decile 9 and 58.96 (95% CI, 33.54–103.65; P <0.001) in highest risk decile 10.

Conclusions—

Presence of ST-depression on the ECG reclassified risk of 30-day mortality in patients with acute heart failure, identifying both high- and low-risk subsets.