Predicting the coronary atherosclerosis severity in cardiac patients

Background. Coronary atherosclerosis is an ongoing pathological process, varying from asymptomatic forms to angina pectoris, myocardial infarction and even sudden cardiac death. Early identification of persons with an increased risk of the severe atherosclerosis will promote adequate diagnostic and therapeutic measures to prevent cardiovascular complications. Aim. To make a prognostic model determining the probability of a severe coronary atherosclerosis in cardiac patients. Material and methods. The actual study included 116 patients of cardiology departments with various degree of coronary atherosclerosis measured by coronary angiography: group I 70% coronary stenosis (50% in case of left main coronary artery), group II those with less severe atherosclerotic process. All patients underwent electrocardiography (ECG) at rest and Holter monitoring. Pathological Q-waves, qualitative and quantitative characteristics of ventricular extrasystoles as well as QRS-fragmentation were assessed in all cases. In individuals having sinus rhythm, heart rate turbulence (HRT), T-wave alternans and QT, QTc dispersion on maximum and minimum heart rate were additionally calculated. Results. The prognostic model included the following ECG-markers: HRT, pathological Q-waves, QTc dispersion on maximum heart rate and QRS-fragmentation in lateral leads (I, AVL, V6). All parameters have demonstrated a direct relationship with the likelihood of severe coronary atherosclerosis. The current model took into account 71% of the factors influencing significant atherosclerosis, AUC=0.940.04, the sensitivity and the specificity were 90.0 and 94.4% respectively. Conclusion. A comprehensive assessment of the ECG data helps to identify the group with an increased risk of severe coronary atherosclerosis among cardiac patients.

Assessment of Transmural Dispersion of Repolarization in Children with Mitral Valve Prolapse

Background: Children with mitral valve prolapse (MVP) may be prone to ventricular arrhythmias due to transmural dispersion of repolarization (TDR). This study aimed to assess alterations in ventricular repolarization in children with MVP and to investigate their relationships with the degree of mitral regurgitation. Methods: Fifty children with MVP and 50 age- and sex-matched healthy children as controls were studied. Twelve-lead electrocardiography and echocardiography were performed in all the subjects. TDR parameters were QT and QTc intervals, QTc dispersion, Tp-e interval, Tp-e interval dispersion, Tp-e/QT, Tp-e/QTc, JTc, JTc dispersion, Tp-e/JT, and Tp-e/JTc. Results: The mean age of the 50 patients with MVP was 12.45±2.50 years (F/M: 15/35). There were no significant differences in QT and QTc intervals between the 2 groups. QTc dispersion (P=0.001), Tp-e dispersion interval (P=0.002), Tp-e/QTc (P=0.001), JTc dispersion (P=0.023), Tp-e/JT (P=0.004), and Tp-e/JTc (P=0.002) were significantly higher in the patients with MVP than in the healthy controls. Positive correlations were found between Tp-e dispersion interval and Tp-e/QTc and an increase in the degree of mitral regurgitation (P=0.012, r=0.42 and P=0.004, r=0.31, respectively). Additionally, positive correlations were detected between JTc dispersion and Tp-e/JTc and an increase in the degree of mitral regurgitation (P=0.032, r=0.20 and P=0.024, r=0.42, correspondingly). Conclusion: In this study, TDR was damaged in children with MVP and was positively correlated with an increase in the degree of mitral regurgitation. It appears that children with MVP are prone to life-threatening ventricular arrhythmias.

Left Ventricular Contraction Duration Is the Most Powerful Predictor of Cardiac Events in LQTS: A Systematic Review and Meta-Analysis

Background: Long-QT syndrome (LQTS) is primarily an electrical disorder characterized by a prolonged myocardial action potential. The delay in cardiac repolarization leads to electromechanical (EM) abnormalities, which adds a diagnostic value for LQTS. Prolonged left ventricular (LV) contraction was identified as a potential risk for arrhythmia. The aim of this meta-analysis was to assess the best predictor of all EM parameters for cardiac events (CEs) in LQTS patients. Methods: We systematically searched all electronic databases up to March 2020, to select studies that assessed the relationship between echocardiographic indices—contraction duration (CD), mechanical dispersion (MD), QRS onset to peak systolic strain (QAoC), and the EM window (EMW); and electrical indices— corrected QT interval (QTC), QTC dispersion, RR interval in relation to CEs in LQTS. This meta-analysis included a total of 1041 patients and 373 controls recruited from 12 studies. Results: The meta-analysis showed that LQTS patients had electrical and mechanical abnormalities as compared to controls—QTC, WMD 72.8; QTC dispersion, WMD 31.7; RR interval, WMD 91.5; CD, WMD 49.2; MD, WMD 15.9; QAoC, WMD 27.8; and EMW, WMD −62.4. These mechanical abnormalities were more profound in symptomatic compared to asymptomatic patients in whom disturbances were already manifest, compared to controls. A CD ≥430 ms had a summary sensitivity (SS) of 71%, specificity of 84%, and diagnostic odds ratio (DOR) >19.5 in predicting CEs. EMW and QTC had a lower accuracy. Conclusions: LQTS is associated with pronounced EM abnormalities, particularly prolonged LV myocardial CD, which is profound in symptomatic patients. These findings highlight the significant role of EM indices like CD in managing LQTS patients.

Increased QT Dispersion Is Linked to Worse Outcomes in Patients Hospitalized for Out‐of‐Hospital Cardiac Arrest

Background The incidence and mortality of out‐of‐hospital cardiac arrest (OHCA) remains high, but predicting outcomes is challenging. Being able to better assess prognosis of hospitalized patients after return of spontaneous circulation would enable improved management of survival expectations. In this study, we assessed the predictive value of ECG indexes in hospitalized patients with OHCA. Methods and Results PR interval and QT interval corrected by the Bazett formula (QTc) for all leads were calculated from standard 12‐lead ECGs 24 hours after return of spontaneous circulation in 93 patients who were hospitalized following OHCA. PR interval and QT and QTc duration did not differentiate OHCA survivors and nonsurvivors. However, QT and QTc dispersion was significantly increased in patients who died during hospitalization compared with survivors discharged from the hospital ( P <0.01). Logistic regression indicated a strong association between increased QT dispersion and in‐hospital mortality ( P <0.0001; area under the curve, 0.8918 for QT dispersion and 0.8673 for QTc dispersion). Multinomial logistic regression indicated that the increase of QTc dispersion correlated with worse Cerebral Performance Category scores at discharge ( P <0.001; likelihood ratio, 51.42). There was also significant correlation between dispersion measures and serum potassium at the time of measurement and between dispersion measures and cumulative epinephrine administration. No difference existed regarding the number of measurable leads. Conclusions Lesser QT and QTc dispersion at 24 hours after return of spontaneous circulation was significantly associated with survival and neurologic status at discharge. Routine evaluation of QT and QTc dispersion during hospitalization following return of spontaneous circulation might improve outcome prognostication for patients hospitalized for OHCA.

Electrocardiography Parameters Changes in Epilepsy and Febrile Convulsion Children Compared with Controls

Epilepsy and febrile convulsion are the most common neurological diseases with significant effect on cardiac functions. The study aimed to evaluate electrocardiography parameters alterations in epilepsy and febrile convulsion children compared with controls. In this comparison study, 270 children analyzed who shared equally in epilepsy, febrile convulsion, and healthy that aged from 0.5 to 5 years. The participants were collected from Ali ibn Abi Talib Hospital of Zahedan, Iran. Epilepsy confirmed based on definition of having at least two unprovoked seizures in 24 hours. Febrile convulsion was confirmed based on its definition by the International League against Epilepsy. Healthy children selected from those referred to the hospital with fever and without any underline diseases. Electrocardiography was performed by a pediatric cardiologist. Data were analyzed using SPSS 19 with p < 0.05 significant level. Heart rate was higher in epilepsy (129.64 ± 27.63) compared with control (108.78 ± 26.01) and febrile convulsion (125.79 ± 25.38; X 2 = 28.701, p < 0.001). S wave in lead V1 was higher in controls (0.72 ± 0.36) compared with epilepsy (0.58 ± 0.45) and febrile convulsion (0.58 ± 0.36). QT dispersion and QTc dispersion levels were higher in epilepsy than febrile convulsion children that both were higher than controls. Concluded that R in aVL, LV mass (LVM), QT dispersion, and QTc dispersion were higher significantly in epilepsy compared with febrile convulsion children. To maintain a good strategic treatment in patients with epilepsy and febrile convulsion, there is a need to assess alternations in ECG parameters, especially QT interval changes that lead to better comprehensive autonomic changes.

Statin Use in the Early Phase of ST-Segment Elevation Myocardial Infarction Is Associated With Decreased QTc Dispersion

Background: Although there is strong evidence supporting the use of statin therapy after myocardial infarction (MI), some mechanistic gaps exist regarding the benefits of this therapy at the very onset of MI. Among the potential beneficial mechanisms, statins may improve myocardial electrical stability and reduce life-threatening ventricular arrhythmia, as reported in stable clinical conditions. This study was designed to evaluate whether this mechanism could also occur during the acute phase of MI. Methods: Consecutive patients with ST-segment elevation MI were treated without statin (n = 57) or with a simvastatin dose of 20 to 80 mg (n = 87) within the first 24 hours after MI symptom onset. Patients underwent digital electrocardiography within the first 24 hours and at the third and fifth days after MI. The QTC dispersion (QTcD) was measured both with and without the U waves. Results: Although QTcD values were equivalent between the groups at the first day (80.6 ± 36.0 vs 80.0 ± 32.1; P = 0.36), they were shorter among individuals using simvastatin than in those receiving no statins on the third (90.4 ± 38.6 vs 86.5 ± 36.9; P = .036) and fifth days (73.1 ± 31 vs 69.2 ± 32.6; P = .049). We obtained similar results when analyzing the QTcD duration including the U wave. All values were adjusted by an ANCOVA model after propensity-score matching. Conclusions: Statins administered within 24 hours of ST-segment elevation MI reduced QTc dispersion, which may potentially attenuate the substrate for life-threatening ventricular arrhythmias.