Myocardial perfusion defect assessed by single-photon emission computed tomography and frontal QRS-T angle in patients with prior anterior myocardial infarction

[Factors associated with an increase in spatial and frontal QRS-T angles in patients with anterior myocardial infarction]

Aim    To determine existence of a relationship between any clinical, echocardiographic and coronarographic factors and increased spatial QRS-T (sQRS-T) angle and frontal QRS-T (fQRS-T) angle in patients with anterior myocardial infarction.Material and methods    This study included 137 patients aged 62 [53; 72] years with anterior acute myocardial infarction managed at the A.L. Myasnikov Institute of Clinical Cardiology. fQRS-T was calculated as the module of difference between the frontal plane QRS complex axis and the T wave axis. sQRS-T was calculated as a spatial angle between QRS and T integral vectors from a synthesized vectorcardiogram.Results    fQRS-T values for a group (median [25th; 75th percentile]) were 81 [37; 120]°; sQRS-T values were 114 [80; 141]°. The correlation coefficient between fQRS-T and sQRS-T values was 0.41 (p<0.001). fQRS-T weakly but statistically significantly correlated with patients' age (r=0.28; p=0.001), left ventricular ejection fraction (LV EF, r= -0.22; p=0.01), and glomerular filtration rate (r=-0.32; p=0.0002). sQRS-T weakly but statistically significantly correlated with left ventricular end-diastolic dimension (r=0.24; p=0.0048), LV EF (r=-0.28; p=0.0009), and the number of affected segments according to echocardiography data (r=0.27; p=0.002). fQRS-T values were significantly higher in the presence of concurrent arterial hypertension. sQRS-T values were significantly higher in the presence of a history of chronic heart failure. Both fQRS-T and sQRS-T values increased with increasing number of affected blood vessels and Killip class of acute heart failure.Conclusion    In patients after anterior acute myocardial infarction, increases in fQRS-T and sQRS-T are associated with more severe damage of the vasculature, decreased LV EF, and, thus, more severe clinical course of disease.

Association between T wave morphology parameters and abnormal cardiac SPECT imaging

BACKGROUND

T-wave morphology dispersion (TMD) described the electrocardiographic T-wave heterogeneity during a single cardiac cycle. Total cosine R-to-T (TCRT) is the average of the cosines of the angles between the QRS and T vectors on the ECG. We examine the predictive value of TMD and TCRT calculation to assess abnormal myocardial perfusion.

METHODS

Retrospective single center cohort study including all patients referred for evaluation of ischemia by myocardial SPECT scanning with no known history of ischemic heart disease, from 1 January 2019 to 31 December 2019. Study endpoint was the correlation between the calculated TMD and TCRT values and detection of myocardial injury or ischemia by myocardial SPECT.

RESULTS

Among 606 patients, calculated TCRT was 0.401 ± 0.53 for the normal group and 0.283 ± 0.62 for the abnormal group (p = 0.007). Measured TMD was 22.9 ± 16.6 degrees (p < 0.001) in the normal group, compared to 31.5 ± 22.8 degrees (p < 0.001) for the abnormal group.

CONCLUSIONS

The results demonstrate a correlation between the decreased TCRT values and increase TMD and myocardial ischemia seen in SPECT results. The TCRT and TMD can be used as simple and non-invasive markers to predict abnormal SPECT results and ischemic heart disease in patients with no known cardiac history.

Associations of increased spatial QRS-T angle with cardiovascular risk factors: data from the regional sample of ESSE-RF study

Aim. To study the associations of increased spatial QRS-T angle (sQRS-Ta ≥90°) with cardiovascular risk factors (RFs).

Material and methods. We analyzed 1411 electrocardiography (ECG) records of men and women aged 25-64 years from a random regional sample of the Epidemiology of Cardiovascular Diseases and their Risk Factors in Regions of Russian Federation (ESSE-RF) study. Relationships of sQRS-Ta with the following RFs were assessed: hypertension (HTN), systolic blood pressure (SBP) ≥140 mm Hg, diastolic BP (DBP) ≥90 mm Hg, pulse pressure (PP) ≥60 mm Hg; glucose ≥7,0 mmol/l, hypercholesterolemia; hypertriglyceridemia; high-density lipoprotein cholesterol (HDL-C) ≤1,0/1,2 mmol/l in men/women, low-density lipoprotein cholesterol (LDL-C) >3,0 mmol/l; C-reactive protein (CRP) >1 mg/L; overweight, obesity and abdominal obesity; heart rate (HR) >80 bpm; age >52 years.

Results. Weak but significant correlations of sQRS-Ta with age (in women), SBP, DBP, PP, body mass index, waist circumference, lipids, glucose, CRP were revealed. Univariate logistic regression demonstrated significant associations of increased sQRS-Ta with HTN, elevated SBP and PP, overweight, obesity and abdominal obesity, hypercholesterolemia, elevated LDL-C and CRP, hyperglycemia, age >52 years and heart rate >80 bpm. There were no associations of increased sQRS-Ta with male sex, elevated DBP, smoking, hypertriglyceridemia, and low HDL-C levels. The sQRS-Ta associations characteristic of women was similar with associations found among the entire sample. Men with increased sQRS-Ta had no associations with any of analyzed RFs. In multivariate models, increased sQRS-Ta was associated with the following combination of RFs: age >52 years, heart rate >80 bpm, HTN, increased PP, overwaight, and male sex. According to direct stepwise selection among all subjects and in women, the main contribution to sQRS-Ta was made by SBP, age, HDL-C and heart rate.

Conclusion. Despite the significance of stepwise regression model (p=0,0001), the low coefficient of determination R2 may indicate other not yet identified determinants with relevant associations with sQRS-Ta.

Associations of frontal QRS-T angle with left ventricular volume and function derived from ECG-gated SPECT in patients with advanced chronic kidney disease

BACKGROUND

The frontal QRS-T angle is one of markers of ventricular repolarization. We investigated whether or not the frontal QRS-T angle could predict left ventricular (LV) volume and function derived from ECG-gated SPECT in patients with advanced chronic kidney disease (CKD).

METHODS

Two hundred and twelve patients with advanced CKD defined as estimated glomerular filtration rate of < 45 ml min-1/1.73 m2 were enrolled. Wide QRS-T angle was defined as its angle of > 90°, and was considered abnormal. Enlarged LV end-diastolic volume (LVEDV) was defined as LVEDV index of > 76 ml m-2 in men and > 57 ml m-2 in women. Reduced LV ejection fraction (LVEF) was defined as LVEF of < 40%.

RESULTS

Fifty-one patients (24%) had wide QRS-T angle, and 161 patients (76%) had normal QRS-T angle. Patients with wide QRS-T angle had larger SSS [9 (5-16) vs 4 (1-9), p < 0.001], larger LVEDV index (69 ± 29 vs 50 ± 18 ml m-2, p < 0.001) and lower LVEF (47 ± 13 vs 59 ± 12%, p < 0.001) than those with normal QRS-T angle. Multivariate analysis showed that wide QRS-T angle (odds ratio 5.93; 95% CI 2.55-14.33; p < 0.001) was significantly associated with enlarged LVEDV, whereas SSS severity was not. Severely abnormal SSS (odds ratio 3.80; 95% CI 1.16-14.05; p < 0.03) and wide QRS-T angle (odds ratio 5.67; 95% CI 2.10-16.22; p < 0.001) were significantly associated with reduced LVEF.

CONCLUSIONS

Our results suggest that wide QRS-T angle is associated with LV remodeling such as enlarged LVEDV or reduced LVEF in patients with advanced CKD.

Effects of Newly Developed Right Versus Left Bundle Branch Block on the QRS Axis, T-wave Axis and Frontal QRS-T Angle in Patients with a Narrow QRS

Objective The QRS-T angle has been established as a repolarization marker. In the present study, we determined whether or not newly developed bundle branch block (BBB) affected the QRS-T angle in patients with a narrow QRS. Methods Twenty-four patients with newly developed BBB and no adverse cardiac events were retrospectively included. The frontal QRS-T angle was defined as the absolute value of the difference between the frontal plane QRS axis and the T-wave axis. These electrocardiogram parameters were serially measured in the settings of narrow QRS and BBB. Results Twelve patients had newly developed right BBB (RBBB), and 12 had newly developed left BBB (LBBB). The development of RBBB did not affect the QRS axis, T-wave axis of QRS-T angle (41° ±42° to 53° ±65°, p = 0.63). In contrast, the development of LBBB shifted the QRS axis to the left (25° ±29° to -18° ±31°, p = 0.003), resulting in an increased QRS-T angle (72° ±50° to 123° ±39°, p = 0.001). Regarding RBBB, an excellent correlation and agreement were found between the QRS-T angles in the setting of narrow QRS and RBBB (r = 0.88; p <0.001; bias, 2.9° ±20.9°). However, there was a significant bias between the QRS-T angles in the setting of narrow QRS and LBBB (51.9° ±40.4°; p = 0.001). Conclusion Our data suggested that the QRS-T angle in the setting of RBBB reflected the original QRS-T angle in the setting of narrow QRS well, whereas the QRS-T angle in the setting of LBBB did not.

[Factors Associated with the Increase in Spatial and Frontal QRS-T Angles in Patients with Inferior Myocardial Infarction]

Aim      To identify clinical, echocardiographic, and angiographic factors related with an increase in the frontal QRS-T angle (fQRS-T) and the spatial QRS-T angle (sQRS-T) in patients with inferior myocardial infarction.Material and methods  The study included 128 patients aged (median [25th percentile; 75th percentile]) 59.5 [51.5; 67.0] years diagnosed with inferior wall acute myocardial infarction. fQRS-T was calculated as a module of difference between the QRS axis and the Т axis in the frontal plane. sQRS-T was calculated by a synthesized vectorcardiogram as a spatial angle between the QRS and Т integral vectors.Results The fQRS-T for the group was 54.0 [18; 80] and sQRS-T was 80.1 [53; 110]. The correlation coefficient for fQRS-T and sQRS-T values was 0.42 (p&lt;0.001). Both fQRS-T &gt;80° and sQRS-T &gt;110° compared to their lower values were associated with a higher frequency of history of postinfarction cardiosclerosis (44% and 12 %, respectively; p&lt;0.05), a lower left ventricular ejection fraction (51 [47; 60]% at fQRS-T &gt;80° and 55 [50; 60]% at fQRS-T &lt;80° (p&lt;0,05); 49 [44; 57]% at sQRS-T &gt;110° and 57 [51; 60] % at sQRS-T &lt;110° (p&lt;0.01); more frequent development of acute heart failure (16 and 2 %, respectively; p&lt;0.05); and early postinfarction angina (13 and 2 %, respectively; p&lt;0.05). The increased fQRS-T was associated with a higher incidence of damage to the circumflex artery (45 and 20 %, respectively; p&lt;0.05). The increased sQRS-T was associated with a history of arterial hypertension (97 and 76 %, respectively; p&lt;0.05), chronic heart failure (22 and 3 %, respectively; p&lt;0.05), chronic kidney disease (19 and 4 %, respectively; p&lt;0.05), and a larger myocardial lesion (mean number of damaged segments by echocardiography was 3.8 [2; 6] at sQRS-T &gt;110° and 2.6 [1; 4] at sQRS-T &lt;110°; p&lt;0.01). sQRS-T was significantly greater in multivascular damage (87 [68; 121]° than in one- or two-vascular damage (72 [51; 100]°; p&lt;0.05). sQRS-T values were significantly lower with spontaneous reperfusion (66 [29; 79] than without spontaneous reperfusion (77 [55; 115]°; p&lt;0.05).Conclusion      In patients after inferior wall acute myocardial infarction, increases in fQRS-T and sQRS-T were associated with more severe damage of coronary vasculature, decreased left ventricular ejection fraction, and more severe course of disease.

Frontal QRS-T angle and left ventricular diastolic function assessed by ECG-gated SPECT in the absence of significant perfusion abnormality

The frontal QRS-T angle, defined as the angle between QRS and T-wave axes, has recently become an area of research interest. We tested the hypothesis that the frontal QRS-T angle is associated with left ventricular (LV) diastolic function in the absence of significant perfusion abnormality using ECG-gated SPECT. One hundred twenty eight patients with no significant perfusion abnormality and preserved LV ejection fraction were enrolled. The peak filling rate (PFR) and the one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters on ECG-gated SPECT. There were 115 male and 13 female patients with a mean age of 70 ± 9 years. The PFR and 1/3 MFR were 2.1 ± 0.4/s and 1.2 ± 0.3/s, respectively. The frontal QRS-T angle was 33° ± 31°, ranging from 0° to 151°. There were significant associations of frontal QRS-T angle with PFR (r = - 0.29, p = 0.001) and 1/3 MFR (r = - 0.30, p < 0.001). Multivariate linear regression analysis showed that age (β = - 0.25, p = 0.003), heart rate (β = 0.26, p = 0.002), LV ejection fraction (β = 0.43, p < 0.001) and frontal QRS-T angle (β = - 0.16, p = 0.03) were significant factors associated with PFR. Also, heart rate (β = - 0.32, p < 0.001), LV mass index (β = - 0.19, p = 0.03), LV ejection fraction (β = 0.30, p < 0.001) and frontal QRS-T angle (β = - 0.26, p = 0.002) were significant factors associated with 1/3 MFR. Our data suggested that the frontal QRS-T angle was associated with LV diastolic function in the absence of significant perfusion abnormality.

Effects of Myocardial Perfusion Defect on the Frontal QRS-T Angle in Anterior Versus Inferior Myocardial Infarction

Objective The frontal QRS-T angle on a 12-lead electrocardiogram (ECG) has recently become accepted as a variable of ventricular repolarization. We compared the effects of myocardial perfusion defect (MPD) on the frontal QRS-T angle between anterior and inferior myocardial infarction (MI) using single-photon emission computed tomography. Methods The frontal QRS-T angle was defined as the absolute value of the difference between the frontal plane QRS axis and T-wave axis. A QRS-T angle more than 90° was considered abnormal. Patients Forty-two patients with anterior MI and 42 age- and sex-matched patients with inferior MI were enrolled. For controls, 42 age- and sex-matched patients with no MPD were selected. Results The mean frontal QRS-T angles in anterior MI, inferior MI and control subjects were 94.7±46.2°, 26.7±22.1° and 27.0±23.2°, respectively. Compared with controls, the frontal QRS-T angle was larger in anterior MI subjects (p<0.001), and similar in value to that in inferior MI subjects (p=0.69). An abnormal QRS-T angle was frequent in the anterior MI subjects than the inferior MI subjects (55% vs. 2%, p<0.001). In anterior MI subjects, MPD was significantly associated with the T-wave axis (ρ=0.46, p=0.002) and QRS-T angle (ρ=0.47, p=0.002), but was not with the QRS axis (ρ=0.07, p=0.66). In inferior MI subjects, there were no associations between MPD and the ECG variables. Conclusion Our data suggest that the frontal QRS-T angle in inferior MI subjects is not increased as evidently as that in anterior MI subjects.