A Study of Tpeak-Tend/QT Interval Ratio in Predicting Heart Failure in ST-Elevation Myocardial Infarction and Its Correlation With N-terminal Pro B-type Natriuretic Peptide (NT-proBNP)

Background Acute ST-elevation myocardial infarction (STEMI) is the most common cause of mortality across the world. The electrocardiogram (ECG) Tpeak-Tend/QT interval appears to be a measure of the left ventricle's transmural dispersion of repolarization (TDR). Prolongation of this time could indicate adverse cardiac events like heart failure, arrhythmias, etc. Heart failure is a clinical syndrome that includes signs and symptoms such as peripheral edema and high jugular vein pressure. N-terminal pro B-type natriuretic peptide (NT-proBNP) is an effective predictor of left ventricular function and also helps in predicting the disease prognosis. Elevated levels of NT-proBNP are seen in many cases of left ventricular dysfunction. This study aims to evaluate the predictive utility of the Tpeak-Tend/QT interval ratio in predicting major adverse cardiac events (MACEs), such as heart failure, by examining the Tend/QT interval ratio values with NT-proBNP in STEMI. Methodology This cross-sectional study was conducted at a tertiary hospital between April 2024 and June 2024. It included STEMI patients, excluding those with non-STEMI (NSTEMI), valvular heart diseases, bundle branch block, or pacemakers. The patients with a Tpeak-Tend/QT ratio < 0.3 were included in group A, and the Tpeak-Tend/QT ratio > 0.3 in group B. They were monitored for MACE-like heart failure during hospitalization and were compared with a study of the Tpeak-Tend/QT interval ratio in predicting heart failure in STEMI and its correlation with NT-proBNP levels. Results In this study, out of 45 patients, male predominance was observed, with 35 (78%) being men and 10 (22%) being women. In group A, the most common age group was 60-70 years, with 16 (51%) patients; in Group B, it was 50-60 years, with six (42.8%) patients. Out of 31 patients in group A, 25 were male, and six were female. In group B, out of 14 patients, 10 were male, and four were female. In this study, out of the 45 patients included, 12 (85%) among 14 patients who had MACEs like heart failure had a Tpeak-Tend/QT interval ratio of more than 0.3, and their measured NT-proBNP levels were also more than 900 pg/mL, thus showing a statistically significant association between Tpeak-Tend/QT interval ratio and NT-proBNP. Conclusion The present study showed an increased Tpeak-Tend/QT interval ratio and NT-proBNP in patients who developed heart failure in STEMI. As ECG is a readily available and affordable tool, the Tpeak-Tend/QT interval ratio can be used along with conventional markers like NT-proBNP to predict MACE in patients with STEMI.

Patients with Achilles Tendon Rupture Are Prone to Develop Ventricular Arrhythmia

BACKGROUND AND OBJECTIVES

This study aimed to examine the ventricular repolarization (VR) disturbances of patients operated on for acute spontaneous Achilles tendon ruptures (ATRs), by comparing them with a healthy individual control group.

MATERIALS AND METHODS

Between June 2014 and July 2020, a total of 29 patients (28 males, 1 female; mean age: 40 ± 9.78 years; range, 21-66 years) who presented to the emergency department within the first three weeks of injury, and were diagnosed with acute spontaneous ATRs and treated with an open Krackow suture technique, were retrospectively analyzed. Fifty-two healthy individuals (47 males, 5 females; mean age: 39 ± 11.45 years; range, 21-66 years) were recruited as a control group from the cardiology outpatient clinic. Clinical data (demographic features and laboratory parameters (serum glucose, creatinine, hemoglobin, white blood cell count, and lipid profile)) and electrocardiograms (ECGs) were collected from medical records. ECGs were evaluated for heart rate and VR parameters of QRS width, QTc interval, cQTd interval, Tp-e interval, and Tp-e/QT ratio. The clinical data and these ECG parameters were compared between groups.

RESULTS

There was no statistically significant difference between groups, regarding clinical data (all p < 0.05). Among ECG parameters, heart rate, QRS width, QTc interval, and cQTd interval were similar between groups (all p < 0.05). There were two important statistically significant findings of this research: The mean Tp-e interval was longer (ATR group: 72.4 ± 24.7, control group: 58.8 ± 14.5, p: 0.01), and the Tp-e/QT ratio was higher (ATR group: 0.2 ± 0.1, control group: 0.16 ± 0.4, p: 0.027) in the ATR group.

CONCLUSIONS

According to the ventricular repolarization disturbances found in this study, patients with ATR may be at a higher risk of ventricular arrhythmia than healthy people. As a result, ATR patients should be assessed for ventricular arrhythmia risk by an expert cardiologist.

Tp-Te Interval and Tp-Te/QT Ratio Are Valuable Tools in Predicting Poor Outcome in Sepsis Patients

Objective

About 50% of patients with sepsis have different degrees of myocardial inhibition, known as sepsis-induced myocardial dysfunction (SMD), which increases the mortality rate of sepsis. Tp-Te interval and Tp-Te/QT ratio reflect ventricular transmural dispersion repolarization (TDR), and have good predictive value for death in patients with heart disease. This study aimed to investigate the prognostic value of Tp-Te and Tp-Te/QT in patients with sepsis.

Methods

The current study included a total of 625 participants: 201 patients with sepsis, 213 patients with heart failure, and 211 healthy participants. According to the severity and outcome, the patients with sepsis were divided into the sepsis group and the septic shock group, and the death group and the survival group to explore the differences of indicators among subgroups of sepsis. The ROC curve was used to analyze the predictive value of the indicators for deaths of patients with sepsis and calculate the cutoff point. Then, we investigated the incidence of arrhythmia in patients with sepsis with different TDR. The correlation between Tp-Te/QT and the commonly used predictive indicators in ICU was also discussed.

Results

(1) Tp-Te and Tp-Te/QT in patients with sepsis and heart failure (HF) were significantly higher than the control group (p < 0.01). (2) Compared with patients with sepsis, the increase of Tp-Te and Tp-Te/QT is more prominent in patients with HF. Especially, the increase of the Tp-Te/QT was statistically significant (p < 0.001). (3) compared with patients with sepsis (no shock), the Tp-Te, Tp-Te/QT, and SOFA were increased in patients with septic shock (p < 0.05). (4) In the death group, Tp-Te /QT, SOFA, and Apache-II were higher; LVEF was lower than the survival group (p < 0.05). (5) ROC curves showed that Tp-Te/QT, SOFA, and LVEF have predictive values for death (p < 0.05; AUC = 0.808, 0.716, 0.412). The cutoff point of Tp-Te/QT was 0.32. (6) The incidence of arrhythmia is different in patients with sepsis with different TDR. (7) There is a significant correlation between Tp-Te/QT and SOFA (p < 0.001, r = 0.79).

Conclusion

TDR in patients with sepsis is significantly increased, which was between healthy population and patients with HF. Tp-Te and Tp-Te/QT are effective indicators to reflect the severity and poor outcome of patients with sepsis.

Terminal T-wave inversion predicts reperfusion tachyarrhythmias in STEMI

INTRODUCTION

A reliable electrocardiographic predictor of ventricular fibrillation (VF) in patients with ST elevation myocardial infarction (STEMI) is lacking so far. Previous experimental/simulation study suggested a terminal T-wave inversion (TTWI) in ischemia-related ECG leads corresponding to anterior infarct localization as an independent predictor of reperfusion VF (rVF). This T-wave characteristic has never been tested as a rVF predictor in clinical settings. The aim of this study was to test if terminal T-wave inversion (TTWI) at admission ECG (before reperfusion) can serve as a predictor of ventricular fibrillation during reperfusion (rVF) in patients with anterior STEMI undergoing primary PCI.

METHODS AND RESULTS

Study population included consecutive patients with anterior infarct localization admitted for primary PCI (n = 181, age 65 [57; 76] years, 66% male). Of those, 14 patients had rVF (rVF group, age 59 [47; 76] years, 64% male) and patients without rVF comprised the No-rVF group (n = 167, age 65 [57; 76] years, 66% male). Association of TTWI with rVF was analyzed using logistic regression analysis adjusted for relevant clinical and electrocardiographic covariates. The prevalence of TTWI in rVF group was 62% comparing to 23% in the No-rVF group, p = 0.005. TTWI was associated with increased risk of rVF (OR 5.51; 95% CI 1.70-17.89; p = 0.004) and remained a significant predictor after adjustment for age, gender, history of MI prior to index admission, VF before reperfusion, T_peak-T_end, maximal ST elevation, and QRS duration (OR 23.49; 95% CI 3.14-175.91; p = 0.002).

CONCLUSIONS

The terminal T-wave inversion in anterior leads before PCI independently predicted rVF in patients with anterior MI thus confirming the previous experimental/simulation findings.

Prognostic value of infarct-related-lead Tpeak-Tend/QT ratio in patients with ST-segment elevation myocardial infarction

Tpeak-Tend/QT ratio (Tp-e/QT) in patients with ST-segment elevation myocardial infarction (STEMI) is reportedly associated with major adverse cardiac events (MACEs). However, Tp-e/QT measurement methods are controversial, and few studies have clarified the effect of different Tp-e/QT measures on prognosis. Our study is the first to investigate the advantages of the Tp-e/QT measured by infarct-related-lead method in predicting MACEs during hospitalization and long-term mortality in patients with STEMI. A total of 427 STEMI patients undergoing primary percutaneous coronary intervention (PCI) were included in this study. The Tp-e/QT before PCI was measured by traditional 12-lead method and infarct-related-lead method. Outcomes were tested using comparative statistics, logistic regression, receiver operating characteristic (ROC) curve and Kaplan-Meier survival analysis. There were 62 (14.5%) patients who had MACEs in-hospital. Logistic regression showed that the Tp-e/QT in infarct-related-lead was an independent predictor (p < 0.001). The area under the ROC curve (AUC) of the Tp-e/QT in infarct-related-lead was larger than that in the Tp-e/QT in traditional 12-lead (0.889 vs 0.741), and the optimal cutoff value was 0.32. The three-year survival rate of patients in the infarct-related-lead Tp-e/QT < 0.32 group was better than Tp-e/QT ≥ 0.32 group in Kaplan-Meier survival analysis (93.9 vs 87.0%). When stratified according to infarct-related arteries, the results showed that the common odds ratio of patients in Tp-e/QT ≥ 0.32 group occurred MACEs was 1.562, P = 0.038. The infarct-related-lead Tp-e/QT performed better than the traditional 12-lead Tp-e/QT in predicting poor prognosis.

In-Hospital Prognostic Value of Electrocardiographic Parameters Other Than ST-Segment Changes in Acute Myocardial Infarction: Literature Review and Future Perspectives

Electrocardiography (ECG) remains an irreplaceable tool in the management of the patients with myocardial infarction, with evaluation of the QRS and ST segment being the present major focus. Several ECG parameters have already been proposed to have prognostic value with regard to both in-hospital and long-term follow-up of patients. In this review, we discuss various ECG parameters other than ST segment changes, particularly with regard to their in-hospital prognostic importance. Our review not only evaluates the prognostic segments and parts of ECG, but also highlights the need for an integrative approach in big data to re-assess the parameters reported to predict in-hospital prognosis. The evolving importance of artificial intelligence in evaluation of ECG, particularly with regard to predicting prognosis, and the potential integration with other patient characteristics to predict prognosis, are discussed.

Association of QT dispersion with mortality and arrhythmic events-A meta-analysis of observational studies

BACKGROUND

The risk stratification of coronary heart disease (CHD) and/or heart failure (HF) patients with easily measured electrocardiographic markers is of clinical importance. The aim of this meta-analysis is to indicate whether increased QT dispersion (QTd) is associated with fatal and nonfatal outcomes in patients with CHD and/or HF.

METHODS

We systematically searched MEDLINE and Cochrane databases without restrictions until August 15, 2018 using the keyword "QT dispersion". Studies including data on the association between QTd and all-cause mortality, sudden cardiac death (SCD) or arrhythmic events in patients with HF and/or CHD were classified as eligible.

RESULTS

In the analysis including patients with CHD and/or HF, we found that QTd did not differ significantly in patients with SCD compared to no SCD patients while QTd was significantly greater in the group of all-cause mortality patients and in patients who experienced a sustained ventricular arrhythmia. Subgroup analysis showed that in myocardial infarction studies, QTd was significantly higher in patients with an arrhythmic event compared to arrhythmic event-free patients while a nonsignificant difference was found in QTd in patients who died from any cause compared to survivors. Similarly, in HF patients, the QTd was significantly greater in patients with an arrhythmic event while a nonsignificant difference was found regarding all-cause mortality and SCD outcomes.

CONCLUSIONS

QTd has a prognostic role for stratifying myocardial infarction or HF patients who are at higher risk of arrhythmic events. However, no prognostic role was found regarding all-cause mortality or SCD in this patient population.

Evaluation of Tpeak to end/QT and Tpeak to end/QTc ratios in patients with STEMI undergoing percutaneous intervention vs. thrombolytic therapy

INTRODUCTION

The patients with ST-segment Elevation Myocardial Infarction (STEMI) are significantly at increased risk of arrhythmia. Repolarization of myocardium has been evaluated by a series of electrical parameters including T wave peak to T wave end (Tp-Te) and Tp-Te/QT ratio. Which were compared with survival outcomes between two groups of STEMI patients treated with Primary Percutaneous Coronary Intervention (PPCI) and recombinant Tissue Plasminogen Activator (r-TPA).

METHODS

In this prospective study, 188 patients with STEMI were included in the study. 12‑Lead ECGs were obtained from all patients on time of admission and after 24 h after treatment. After dividing the patients into two groups based on their type of treatment (PPCI or r-TPA), The Tp-Te/QT and Tp-Te/QTc ratios were calculated using ECG records. The survival outcomes were compared between two groups.

RESULTS

95 patients (50.5%) underwent PPCI and 93 patients (49.5%) received r-TPA. Tp-Te/QT and Tp-Te/QTc ratios after administration of the treatments were significantly decreased in both groups (P-value = .001) with lower Tp-Te/QT and Tp-Te/QTc ratios in PPCI group (P-value = .001). 7 patients in PPCI group (7.3%) and 16 patients in r-TPA group (17.2%) were died during their hospitalization period (P-value = .04). The best combination of sensitivity and specificity of post treatment Tp-Te/QT ratio was at cutoff points of 29.4 with 82% sensitivity and 83% specificity.

CONCLUSION

Our study demonstrated that Tp-Te/QT and Tp-Te/QTc ratios decrease significantly after both PPCI and r-TPA therapies, but with PPCI these indexes decrease more than r-TPA, resulting a better survival outcome in patients with STEMI.

Prolonged Tpeak -Tend interval is a risk factor for sudden cardiac death in adults with congenital heart disease

Objective

Adult congenital heart disease (ACHD) patients are at risk of sudden cardiac death (SCD). However, methods for risk stratification are not yet well‐defined. The T_peak‐T_end (TpTe) interval, a measure of dispersion of ventricular repolarization, is a risk factor for SCD in non‐ACHD patients. We aim to evaluate whether TpTe can be used in risk stratification for SCD in ACHD patients.

Design

From an international multicenter cohort of 25 790 ACHD patients, we identified all SCD cases. Cases were matched to controls by age, gender, congenital defect, and (surgical) intervention.

Outcome Measures

TpTe was measured on a standard 12‐lead ECG. The maximum TpTe of all ECG leads (TpTe‐max), mean (TpTe‐mean), and TpTe dispersion (maximum minus minimum) were obtained. Odds ratios (OR) for SCD cases vs controls were calculated using conditional logistic regression analysis.

Results

ECGs were available for 147 cases (median age at death 33.5 years (quartiles 26.2, 48.7), 66% male) and 267 controls. The mean TpTe‐max was 97 ± 24 ms in cases vs 84 ± 17 ms in controls (P < .001); TpTe‐mean was 70 ± 16 vs 63 ± 10 ms (P < .001); and dispersion was 51 ± 22 ms vs 41 ± 16 ms (P = .02), respectively. Assessing each ECG lead separately, TpTe in lead aVR predicted SCD most accurately. TpTe in lead aVR was 71 ± 23 ms in cases vs 61 ± 13 ms in controls (P < .001). After adjusting for impaired ventricular function, heart failure symptoms, and prolonged QRS duration, the OR of SCD of TpTe in lead aVR at an optimal cutoff of 80 ms was 5.8 (95% CI 2.7‐12.4, P < .001).

Conclusions

The TpTe interval is associated with SCD in ACHD patients. Particularly, TpTe in lead aVR can be used as an independent risk factor for SCD in ACHD patients and may, therefore, add precision to current risk prediction models.

Noninvasive assessment of left-ventricular diastolic electromechanical coupling in hypertensive heart disease

BACKGROUND

There is a need to stratify patients who may develop heart failure because of the current "heart failure pandemic". We hypothesized that noninvasive assessment of diastolic electromechanical coupling by electrocardiography and Doppler echocardiography may be clinically useful for risk stratification of hypertensive patients who may develop heart failure.

METHODS

We measured the time from the peak to end of the T wave (TpTe) as an electrophysiological parameter, and peak early diastolic mitral flow (E) and lateral annular (e') velocities as mechanical parameters in 109 patients with hypertension. Relationships between these parameters and their association with the prognosis were evaluated.

RESULTS

The e' was inversely correlated with TpTe (p < 0.001) and QTc (p < 0.014), whereas E/e' was positively correlated with TpTe (p < 0.001) and QTc (p < 0.001). The TpTe predicted patients with E/e' > 12. There were 24 cardiovascular events during follow-up (57 ± 20 months), and Kaplan-Meier analysis showed that outcome was worse (p = 0.003) in patients with higher E/e' than lower E/e'; however, there was no difference between patients with longer TpTe (≧72 ms) and shorter TpTe (< 72 ms).

CONCLUSION

The correlation of TpTe with e' and E/e' in hypertensive patients suggests that these parameters reflect diastolic ventricular electromechanical coupling. The E/e' predicted outcome, and an elevated E/e' should be suspected when TpTe is prolonged (> 72 ms). Noninvasive evaluation of diastolic electromechanical coupling is clinically useful in patients with hypertension for predicting their outcome.

Evaluation of the impact of treatment with hematopoietic stem cells transplantation (HSCT) on biochemical markers of heart function and novel electrocardiographic markers of repolarization in patients with hematological malignancies

High-dose chemotherapy (HDC) followed by stem cell transplantation (HSCT) is a well-established method in patients with hematological malignancies, and for last few years, many efforts have been made to estimate short- and long-term efficacy of this method, as well as early and late complications. The present study concentrates on cardiotoxic effects, mainly early changes using biochemical markers such as N-terminal natriuretic peptide type B (NT-proBNP) and cardiac troponins (cTn). Simultaneously, the analysis of 12-lead ECG was done before and after the procedure in which the novel repolarization markers: T_p-e and T_p-e/QT ratio were measured, together with standard markers: QT, QTc. It was found that NT-pro BNP was significantly increased after HSCT in comparison to results before it, and no significant changes were present in Troponin levels. Simultaneously, T_p-e interval and T_p-e/QT ratio were significantly higher after HSCT. The use of cyclophosphamide, advanced age, and higher level of blood cholesterol concentration were risk factors for the increase in NT-proBNP and treatment with cyclophosphamide as well as fludarabine and higher creatinine levels were risk factors for the increase in T_p-e/QT ratio. In conclusion, in the early term evaluation after HSCT in patients with no previously diagnosed heart disease, the mild changes in markers of heart overload and repolarization were noted. The observations suggest that in all patients undergoing HSCT, even the ones without pre-existing cardiovascular disease, the evaluation, and monitoring of heart function should be considered.

Tpeak-Tend/QT interval predicts ST-segment resolution and major adverse cardiac events in acute ST-segment elevation myocardial infarction patients undergoing percutaneous coronary intervention

Elevated ST-segment and increased Tpeak-Tend interval (Tp-e) were prognostic predictors in major adverse cardiac events (MACEs) in ST-segment elevation myocardial infarction (STEMI). The electrophysiologic relationship between them during percutaneous coronary intervention (PCI) needs to elucidate.Patients with STEMI admitted to hospital were prospectively evaluated. ST-segment resolution (STR) (defined as ≥50% reduction as the complete-STR [CSTR] group, <50% as incomplete-STR [ISTR] group), Tp-e interval, and ratio of Tp-e to QT interval (Tp-e/QT) were measured, calculated and analyzed with MACEs.Tp-ec interval (corrected Tp-e interval, P < .001) and Tp-e/QT ratio (P < .001) were significantly increased by myocardial infarction and partly recovered post-PCI. Patients with ISTR showed more increased Tp-ec interval (P < .001) and Tp-e/QT ratio (P < .001) than those in CSTR groups post-PCI. In multivariate analysis and receiver operating characteristic curves analysis, Tp-e/QT was an independent and strongest predictor for STR. STR and electrocardiogram parameters with a cutoff value for predicting STR showed prognostic value for MACE in STEMI in Kaplan-Meier survival analysis.Both STR and change of Tp-e parameters were not only predictors of arrhythmia, but also prognostic factors of MACE in patients with STEMI after PCI.

T-Wave Indices and Atherosclerosis

Tpeak-Tend interval, the time difference between the peak and the end of the T-wave, reflects the degree of dispersion of repolarization. Its prolongation has been associated with higher risks of developing ventricular arrhythmias and sudden cardiac death in different pro-arrhythmic conditions such as Brugada and long QT syndromes. In this review, we will provide a comprehensive overview on how Tpeak-Tend is altered in different atherosclerotic conditions such as hypertension, stable coronary artery disease, acute coronary obstruction, and coronary slow flow as well as inflammatory diseases affecting the arterial tree. We will explore its relationship with arterial function and dysfunction, ventricular remodeling, and arrhythmic and mortality outcomes. The published literature shows that patients with coronary atherosclerosis, whether in the form of stable coronary artery disease, chronic total occlusion, slow flow, or acute coronary obstruction, have prolonged Tpeak-Tend intervals and Tpeak-Tend/QT ratios. These can be used to predict the occurrence of ventricular arrhythmias and sudden cardiac death. They also correlate with the extent and severity of arterial stenosis and structural remodeling of the ventricles as well as arterial function and dysfunction. Finally, they can be normalized following revascularization and may therefore be used as a surrogate measure of treatment success.

The assessment of P-wave dispersion and myocardial repolarization parameters in patients with chronic kidney disease

Objective: The risks of sudden death and cardiac arrhythmia are increased in patients with chronic kidney disease (CKD). Here, we aimed to evaluate the indicators of arrhythmias, such as p-wave dispersion (P-WD), QTc dispersion, Tp-e and Tp-e/QT ratio in patients with CKD stages 3–5 on no renal replacement therapy (RRT).

Material and methods: One-hundred and thirty three patients with CKD stages 3–5 and 32 healthy controls were enrolled into the study. No patients received RRT. QTc dispersion, P-WD and Tp-e interval were measured using electrocardiogram and Tp-e/QT ratio was also calculated.

Results: Mean age rates were found similar in patients and controls (60.8 ± 14.2 and 61 ± 12.9 y, p = .937, respectively). Compared patients with controls, P-WD (45.85 ± 12.42 vs. 21.17 ± 6.6 msec, p < .001), QTc-min (366.99 ± 42.31 vs. 387.15 ± 20.5 msec, p < .001), QTc dispersion (71.13 ± 27.95 vs. 41.25 ± 14.55 msec, p < .001), Tp-e maximum (81.04 ± 10.34 vs. 75.49 ± 10.9 msec, p < .001), Tp-e minimum (62.25 ± 7.58 vs. 54.8 ± 6.72 msec, p < .001) and Tp-e/QTc ratio (0.19 ± 0.02 vs. 0.18 ± 0.01, p = .001) were found to be different. QTc-max and Tp-e interval were found to be similar in both groups.

Conclusion: P-WD and QTc dispersion, Tp-e interval and Tp-e/QTc ratio were found to be increased in with CKD stages 3–5 on no RRT.

Tpeak-Tend dispersion as a predictor for malignant arrhythmia events in patients with vasospastic angina

BACKGROUND

Tpeak-Tend interval (Tp-e interval) in electrocardiogram (ECG) has been reported to predict malignant arrhythmia events (MAE) in ST-segment elevation myocardial infarction and ion channelopathy. Tp-e interval and other ECG parameters as predictors for MAE was evaluated in patients with vasospastic angina (VA).

METHODS AND RESULTS

Sixty-two patients with VA (Non-MAE group) and 20 patients with VA complicated by MAE (MAE group) were enrolled in our Division of Cardiology between January 2010 and December 2015. Continuous variables were analyzed by t-test and categorical variables by Chi-square analysis. Patients with MAE showed greater QTc (corrected QT interval) dispersion (P=0.005), Tp-ec (corrected Tp-e) interval (P=0.001), Tp-ec dispersion (P<0.001) and Tp-e/QT ratio (P<0.001) than those in non-MAE groups when ST-segment elevated. After elevated ST-segment returned, there were no significant differences in these ECG parameters between two groups (All P>0.05). At univariate binary logistic regression analysis QTc dispersion (odds ratio(OR)=1.133; P=0.013), Tp-ec (OR=1.058; P=0.003), Tp-e/QT (OR=1.403; P=0.001), and Tp-ec dispersion (OR=1.497; P=0.004) were significantly associated with MAE. At multivariable logistic regression analysis, Tp-ec dispersion remained a predictor of MAE. Receiver operating characteristic (ROC) curve analysis showed that only AUC (Area under curve) of Tp-ec dispersion had significant difference with those in QTc dispersion (P<0.001), Tp-ec (P=0.003), and Tp-e/QT ratio (P=0.012), respectively.

CONCLUSIONS

QTc dispersion, Tp-ec, Tp-e/QT and Tp-ec dispersion were significantly increased in VA patients with MAE than those without MAE when coronary spasm was onset. Prolonged Tp-ec dispersion was the best discriminators and a strong independent predictor of MAE in VA patients.