Prognostic significance of inverse spatial QRS-T angle circadian pattern in myocardial infarction survivors

The relationship of frontal QRS-T angle between patients with newly diagnosed true and white coat hypertension

OBJECTIVES

The frontal QRS-T (f-QRST) angle is a measure of depolarization and repolarization heterogeneity and may be a predictor of poor ventricular health. We aimed to investigate whether the f-QRST angle indicates myocardial damage and predicts newly diagnosed true hypertension (HT) in patients with white coat hypertension.

METHODS

We measured the f-QRST angle of 63 subjects with WHC and 105 patients with newly diagnosed HT. Laboratory tests and ABPM were followed up in all patients. The f-QRST angle was calculated on the surface ECGs.

RESULTS

Of the patients in the study, 38.9% were female and 61.1% were male. The mean age was calculated as 59 ± 11 years. A comparison between both groups with the f-QRST angles was seen to be statistically significantly higher in the true HT group. The results of the receiving operating characteristic curve showed that the AUC value of the f-QRST angle was 0.94 (95% confidence interval, 0.91-0.97), the cutoff value was 60.5°, the sensitivity was 89.5%, and the specificity was 81%.

CONCLUSION

In our study, the f-QRST angle was found to be lower in patients with WHC than in true hypertensive patients. We think that ECG, which is a simple test, can be used to distinguish between true HT and WHC.

The impact of midazolam used in cataract surgery sedation on frontal QRS-T angle

WHAT IS KNOWN AND OBJECTIVE

Midazolam is one of the most commonly used drugs in procedures requiring sedoanalgesia. It affects the myocardium's ventricular depolarization and repolarization. Previous studies examining the arrhythmogenic effects of midazolam yielded conclusive results. These studies are based on QT and Tp -e distances. The frontal QRS-T angle (f-[QRS-T]a) is a new electro cardiac parameter that shows the heterogeneity of ventricular electrical activity. This study aims to examine the effect of midazolam on f-(QRS- T)a and other depolarization-repolarization parameters in patients who have had cataract surgery.

METHODS

The study included 177 patients administered midazolam as a sedoanalgesia during cataract surgery. The sedative effect was evaluated 2-3 minutes after a 0.05 mg/kg dose of midazolam was given. Sedation was assessed again by giving 0.5 mg every 2-3 minutes until the desired level of sedation was achieved. 12-lead electrocardiogram (ECG) recordings of all patients were taken just before and immediately after surgery. ECGs were used to calculate the QT interval, QTc interval, Tp -e interval, Tp -e/QT, Tp -e/ QTc ratios and f-(QRS-T)a.

RESULTS AND DISCUSSION

After cataract surgery, f-(QRS-T)a was unchanged compared to presurgery (29.14 ± 4.52 vs. 29.18 ± 5.39, p = 0.852). In addition, no significant change in QT(351.32 ± 21.98 vs. 351.94 ± 22.44, p = 0.091), QTc (384.05 ± 24.52 vs. 385.19 ± 26.12, p = 0.819), Tp -e interval (93.12 ± 9.60 vs. 94.44 ± 8.82, p = 0.179) and Tp -e/QT (0.27 ± 0.02 vs. 0.28 ± 0.03, p = 0.664), Tp -e/ QTc ratios (0.28 ± 0.02 vs. 0.29 ± 0.03, p = 0.655) was observed after surgery when compared to presurgery values. Significant ventricular and supraventricular arrhythmias were not observed in any patient during the operation.

WHAT IS NEW AND CONCLUSION

Midazolam did not affect f -(QRS-T) with classical repolarization parameters in patients who underwent cataract surgery, according to this study. Midazolam has been found to be safe for the heart in sedoanalgesia. These results show that sedation with midazolam can be performed without electrocardiogram monitoring.

Relationship between frontal QRS-T duration and the severity of coronary artery disease in who were non-diabetic and had stable angina pectoris

OBJECTIVE

There is a known relationship between frontal-QRS-T (F-QRS-T) angle and coronary artery disease (CAD). This study examined the relationship between F-QRS-T angle changes and CAD severity in patients with stable CAD.

METHODS

A total of 202 patients were included in the study after the implementation of exclusion criteria among 894 patients, who were admitted to the outpatient clinic with stable angina pectoris between September 2018 and September 2019. The F-QRS-T angle calculated on the 12-lead electrocardiograms (ECGs) of the patients (taken in the outpatient clinic), and the CAD severity calculated using the Gensini score in patients undergoing coronary angiography were compared.

RESULTS

Of the patients included in the study, 38.6% were female and 61.4% were male. The mean age was calculated as 60.16±11.27 years, and 52% of the patients had hypertension. There was no difference between the groups in terms of demographic and clinical values. In a comparison of CAD severity and F-QRS-T angles, the F-QRS-T angle was seen to be statistically significantly higher in the severe CAD group [91°° (102/79)] compared to the group with mild CAD [53°° (64/38)]. In the multivariate logistic regression analysis, there was a significant association between the F-QRS-T angle (odds ratio=1.09, 95% confidence interval=1.06-1.11, p<0.001) and CAD severity.

CONCLUSION

It seems that CAD severity in patients who were non-diabetic and had stable angina pectoris is associated with the F-QRS-T angle.

Improvement of the frontal QRS-T angle after successful percutaneous coronary revascularization in patients with chronic total occlusion

BACKGROUND

The QRS-T angle (QRS-Ta) is a novel marker of myocardial repolarization heterogeneity which is related to adverse cardiovascular events. Our aim in this study was to investigate the effect of successful percutaneous coronary intervention (PCI) on frontal QRS-Ta in patients with chronic total occlusion (CTO).

MATERIALS AND METHODS

A total of 132 patients undergoing PCI for CTO were included in this study. Successful PCI of CTO segment was performed in 84 patients (group 2) while 48 who failed CTO were observed (group 1). Baseline demographic and clinical variables were evaluated and, 12-lead surface ECGs of all subjects were recorded before performing coronary angiography and 1-month and 6-month after the index procedure.

RESULTS

QRS-Ta values significantly decreased during follow-up visits compared to baseline values [92.5 (63.25-110.75); 85.0 (59.0-101.0); 80.0 (53.0-99.0), P < 0.001] in group 2 patients. Moreover, there was no significant difference in frontal QRS-Ta measurements in group 1 patients in their clinical 6-month follow-up [87.0 (48.25-103.0); 86.5 (46.0-101.75); 84.0 (49.0-103.75); P = 0.320]. First month frontal QRS-Ta values [92.5 (63.25-110.75); 85.0 (59.0-101.0), P = 0.002] and sixth month frontal QRS-Ta values [92.5 (63.25-110.75); 80.0 (53.0-99.0), P < 0.001] were lower than baseline values while sixth month values [85.0 (59.0-101.0); 80.0 (53.0-99.0), P = 0.002] was lower compared to first month values. Additionally, a decrease in frontal QRS-Ta was observed regardless of target vessel or Rentrop classification.

CONCLUSION

Successful percutaneous revascularization of CTO was effective in ventricular repolarization. Frontal QRS-Ta significantly decreased after successful PCI on CTO patients at a 6-month follow-up.

Frontal QRS-T angle is related with hemodynamic significance of coronary artery stenosis in patients with single vessel disease

OBJECTIVE

Fractional flow reserve (FFR) measurement is used to decide the hemodynamic significance of coronary artery lesion. QRS-T angle (QRSTa) is a novel marker of myocardial repolarization abnormality and is affected by obstructive coronary artery disease. The aim of the present study was to evaluate the association between QRSTa and coronary FFR measurement in patients with isolated left anterior descending (LAD) artery stenosis.

METHODS

A total of 197 patients undergoing FFR measurement for isolated LAD artery stenosis were retrospectively enrolled in the present study. According to FFR value, patients were divided into two groups as 139 patients with normal FFR (>0.80, group 1) and 58 patients with low FFR (≤0.80, group 2). A 12-lead surface electrocardiography of all subjects that had been recorded before performing coronary angiography was evaluated to measure QRSTa, as well as baseline demographic and clinical variables.

RESULTS

The mean age of group 2 was significantly higher than that of group 1 (61±11 and 64±11, p=0.044). While there were no differences in heart rate, QRS duration, and corrected QT interval between the two groups, QT interval [377 (359-397) and 379 (367-410), p=0.045] and frontal QRSTa [59 (10-120) and 86 (22-132), p<0.001] were higher in group 2. QT interval [odds ratio (OR)=1.046, 95% confidence interval (CI)=1.010-1.084, p=0.012] and frontal QRSTa (OR=1.025, 95% CI=1.010-1.041, p=0.001) were found to be independent predictors of low FFR value in multivariate logistic regression analysis.

CONCLUSION

In the present study, FFR measurement was demonstrated to be correlated with wide QRSTa as a noninvasive and easy method. Thus, we suggest that the results of FFR measurement as an invasive modality can be previously predicted with a simple electrocardiographic evaluation, such as QRSTa.

Prognostic value of frontal QRS-T angle in patients undergoing myocardial revascularization or cardiac valve surgery

BACKGROUND

An abnormal frontal QRS-T angle (fQRSTa) is associated with increased risk of death in primary and secondary cardiovascular prevention. The aim of this study was to evaluate the fQRSTa prognostic role in patients undergoing myocardial revascularization and/or cardiac valve surgery.

METHODS

We enrolled and prospectively followed for 48 ± 26 months 939 subjects with available QRS and T axis data; mean age was 68 ± 12 years, 449 patients (48%) underwent myocardial revascularization, 333 (35%) cardiac valve surgery, 94 (10%) valve plus bypass graft surgery and 63 (7%) cardiac surgery for other cardiovascular (CV) diseases. The ECG variables were collected at the end of the cardiac rehabilitation program and fQRSTa was considered normal if <60°, abnormal if >120°, borderline otherwise. Endpoints were overall and CV mortality.

RESULTS

The fQRSTa was normal in 333 patients (36%), borderline in 285 (30%) and abnormal in 321 (34%). Overall (p = 0.012) and cardiovascular (p = 0.007) mortality were significantly higher in patients with abnormal fQRSTa even after adjusting separately for gender, PR-, QTc- intervals, presence of right or left bundle branch block and left atrial volume index. The predictive value was confirmed in patients with stable coronary artery disease (SCAD), not in patients with acute coronary syndrome or valve disease. SCAD patients with abnormal both fQRSTa and QRS axis had higher risk of overall (hazard ratio = 2.9, p < 0.0001) and CV (hazard ratio = 4.4, p < 0.0001) mortality compared with SCAD patients with normal fQRSTa, even after multivariate adjustment for age, gender, ECG intervals, left-ventricle ejection fraction and mass index.

CONCLUSIONS

In SCAD patients undergoing myocardial revascularization, abnormal fQRSTa is independent predictor of overall and CV mortality.

Changes of Virtual Planar QRS and T Vectors Derived from Holter in the Populations with and without Diabetes Mellitus

Aims

Research related to type 2 diabetes mellitus (DM) and parameters of electrocardiography (ECG) was limited. Patients with and without DM (NDM) were randomly enrolled in a study to exploit the influence of DM on planar QRS and T vectors derived from the Virtual Holter process.

Methods

A total of 216 (NDM) and 127 DM patients were consecutively and randomly recruited. We selected a 1‐minute length of ECG, which was scheduled for analysis at 4 AM. After a series of calculating algorisms, we received the virtual planar vector parameters.

Results

Patients with DM were elderly (65.61 ± 12.08 vs 59.41 ± 16.86 years, P < 0.001); higher morbidity of hypertension (76.38% vs 58.14%, P < 0.001) and coronary artery disease (44.09% vs 32.41%, P = 0.03); thicker interventricular septum (10.92 ± 1.77 vs 10.08 ± 1.96 mm, P < 0.001) and left ventricular posterior wall (9.84 ± 1.38 vs 9.39 ± 1.66 mm, P = 0.03); higher lipid levels and average heart rate (66.67 ± 12.04 vs 61.87 ± 13.36 bpm, P < 0.01); higher angle of horizontal QRS vector (HQRSA, –2.87 ± 48.48 vs –19.00 ± 40.18 degrees, P < 0.01); lower maximal magnitude of horizontal T vector (HTV, 2.33 ± 1.47 vs 2.88 ± 1.89 mm, P = 0.01) and maximal magnitude of right side T vector (2.77 ± 1.55 vs 3.27 ± 1.92 mm, P = 0.03), and no difference in angle of frontal QRS‐T vector (FQRSTA, 32.77 ± 54.20 vs 28.39 ± 52.87 degrees, P = 0.74) compared with patients having NDM. After adjusting for confounding factors, DM was significantly effective on FQRSTA (regression coefficient –40.0, 95%CI –66.4 to –13.6, P < 0.01), HQRSA (regression coefficient 22.6, 95%CI 2.5 to 42.8, P = 0.03), and HTV (regression coefficient 0.9, 95%CI 0.2 to 1.7, P = 0.01). Confounding factors included: sex, 2‐hour postprandial blood glucose, smoking, triglyceride, apolipoprotein A, creatinine, left ventricular ejection fraction, and average heart rate.

Conclusions

The risk factors of DM and lipid metabolism abnormality particularly apolipoprotein A significantly modified parameters of virtual planar QRS and T vector, including frontal QRS‐T angle.