QT Interval Dynamics and Cardiovascular Outcomes: A Cohort Study in an Integrated Health Care Delivery System

Autonomic Dysfunction and Cardiovascular Risk in Patients with Rheumatoid Arthritis: Can Heart Rate Variability Analysis Contribute to a Better Evaluation of the Cardiovascular Profile of a Patient?

(1) Background: Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune etiology. Increased scientific evidence suggests that immune-mediated inflammatory dis-eases are associated with autonomic nervous system (ANS) dysfunction. Studies proved that autonomic imbalance is correlated with RA evolution and may explain augmented cardiovascular pathology and mortality not attributable to classical risk factors. (2) Methods: 75 patients (25 males, 50 females) with RA were submitted to standard ECG recording and 24 h Holter monitoring. Twenty-five healthy patients were used as controls. Both time (SDNN, SDANN, SDANN Index, RRmed, rMSSD, and pNN50) and frequency domain (TP, VLF, HF, LF and LF/HF) heart rate variability (HRV) parameters were obtained. Parameters were compared to controls, and correlations with the QTc-interval and inflammatory status expressed through the C-reactive protein (CRP) were evaluated. (3) Results: In patients with a CRP > 5 mg/L, HRV parameters were lower compared to controls and to patients with a CRP ≤ 5 mg/L. All HRV parameters generated by Holter monitoring are negatively correlated with CRP levels and QTc values. The number of premature ventricular contractions (PVC) recorded is correlated with SDNN, SDANN, and LF/HF values. (4) Conclusions: Our study supports recent data suggesting that in RA there is an autonomic system dysfunction strongly connected with the inflammatory status of the patient. The autonomic dysfunction can contribute to the increased risk of cardiovascular death observed in patients with RA.

The optimal QTc selection in patients of acute myocardial infarction with poor perioperative prognosis

BACKGROUND

The predictive utility of QTc values, calculated through various correction formulas for the incidence of postoperative major adverse cardiovascular and cerebrovascular events (MACCE) in patients experiencing acute myocardial infarction (AMI), warrants further exploration. This study endeavors to ascertain the predictive accuracy of disparate QTc values for MACCE occurrences in patients with perioperative AMI.

METHODS

A retrospective cohort of three hundred fourteen AMI patients, comprising 81 instances of in-hospital MACCE and 233 controls, was assembled, with comprehensive collection of baseline demographic and clinical data. QTc values were derived employing the correction formulas of Bazett, Fridericia, Hodges, Ashman, Framingham, Schlamowitz, Dmitrienko, Rautaharju, and Sarma. Analytical methods encompassed comparative statistics, Spearman correlation analysis, binary logistic regression models, receiver operating characteristic (ROC) curves, and decision curve analysis (DCA).

RESULTS

QTc values were significantly elevated in the MACCE cohort compared to controls (P < 0.05). Spearman's correlation analysis between heart rate and QTc revealed a modest positive correlation for the Sarma formula (QTcBaz) (ρ = 0.46, P < 0.001). Within the multifactorial binary logistic regression, each QTc variant emerged as an independent risk factor for MACCE, with the Sarma formula-derived QTc (QTcSar) presenting the highest hazard ratio (OR = 1.025). ROC curve analysis identified QTcSar with a threshold of 446 ms as yielding the superior predictive capacity (AUC = 0.734), demonstrating a sensitivity of 60.5% and a specificity of 82.8%. DCA indicated positive net benefits for QTcSar at high-risk thresholds ranging from 0 to 0.66 and 0.71-0.96, with QTcBaz, prevalent in clinical settings, showing positive net benefits at thresholds extending to 0-0.99.

CONCLUSION

For perioperative AMI patients, QTcSar proves more advantageous in monitoring QTc intervals compared to alternative QT correction formulas, offering enhanced predictive prowess for subsequent MACCE incidents.

Environmental pollutant pre- and polyfluoroalkyl substances are associated with electrocardiogram parameters disorder in adults

Environmental pollutants exposure might disrupt cardiac function, but evidence about the associations of per- and polyfluoroalkyl substances (PFASs) exposure and cardiac conduction system remains sparse. To explore the associations between serum PFASs exposure and electrocardiogram (ECG) parameters changes in adults, we recruited 1229 participants (mean age: 55.1 years) from communities of Guangzhou, China. 13 serum PFASs with detection rate > 85% were analyzed finally. We selected 6 ECG parameters [heart rate (HR), PR interval, QRS duration, Bazett heart rate-corrected QT interval (QTc), QRS electric axis and RV5 + SV1 voltage] as outcomes. Generalized linear models (GLMs) and Bayesian kernel machine regression (BKMR) model were conducted to explore the associations of individual and joint PFASs exposure and ECG parameters changes, respectively. We detected significant associations of PFASs exposure with decreased HR, QRS duration, but with increased PR interval. For example, at the 95th percentile of 6:2 Cl-PFESA, HR and QRS duration were - 6.98 [95% confidence interval (CI): - 9.07, - 4.90] and - 6.54(95% CI: -9.05, -4.03) lower, but PR interval was 7.35 (95% CI: 3.52, 11.17) longer than those at the 25th percentile. Similarly, significant joint associations were observed in HR, PR interval and QRS duration when analyzed by BKMR model.

Changes of ECG parameters after BNT162b2 vaccine in the senior high school students

The purpose of this study is to determine the ECG parameter change and the efficacy of ECG screening for cardiac adverse effect after the second dose of BNT162b2 vaccine in young population. In December 2021, in cooperation with the school vaccination system of Taipei City government, we performed a ECG screening study during the second dose of BNT162b2 vaccines. Serial comparisons of ECGs and questionnaire survey were performed before and after vaccine in four male-predominant senior high schools. Among 7934 eligible students, 4928 (62.1%) were included in the study. The male/female ratio was 4576/352. In total, 763 students (17.1%) had at least one cardiac symptom after the second vaccine dose, mostly chest pain and palpitations. The depolarization and repolarization parameters (QRS duration and QT interval) decreased significantly after the vaccine with increasing heart rate. Abnormal ECGs were obtained in 51 (1.0%) of the students, of which 1 was diagnosed with mild myocarditis and another 4 were judged to have significant arrhythmia. None of the patients needed to be admitted to hospital and all of these symptoms improved spontaneously. Using these five students as a positive outcome, the sensitivity and specificity of this screening method were 100% and 99.1%, respectively.  Conclusion: Cardiac symptoms are common after the second dose of BNT162b2 vaccine, but the incidences of significant arrhythmias and myocarditis are only 0.1%. The serial ECG screening method has high sensitivity and specificity for significant cardiac adverse effect but cost effect needs further discussed. What is Known: • The incidence of cardiac adverse effects was reported to be as high as 1.5 per 10 000 persons after the second dose BNT162b2 COVID-19 vaccine in the young male population based on the reporting system. What is New: • Through this mass ECG screening study after the second dose of BNT162b2 vaccine we found: (1) The depolarization and repolarization parameters (QRS duration and QT interval) decreased significantly after the vaccine with increasing heart rate; (2) the incidence of post-vaccine myocarditis and significant arrhythmia are 0.02% and 0.08%; (3) The serial ECG screening method has high sensitivity and specificity for significant cardiac adverse effect.

THE ROLE OF LEFT VENTRICULAR HYPERTROPHY, RS1801253 AND RS1801252 ALLELIC POLYMORPHISMS OF ADRB1 IN ASSESSING THE RISK OF SUDDEN CARDIAC DEATH IN PATIENTS WITH ARTERIAL HYPERTENSION

OBJECTIVE

The aim: To study the association of left ventricular hypertrophy (LVH) and polymorphisms rs1801253 and rs1801252 of the ADRB1 gene with the risk of sudden cardiac death (SCD).

PATIENTS AND METHODS

Materials and methods: The study included 179 patients which underwent clinical investigation, echocardiography, elektrokardiography. The examined were divided into groups with a low (110 people) and high risk (69 people) of SCD. The distribution of allelic polymorphisms was investigated with polymerase chain reaction (PCR).

RESULTS

Results: All patients of group with high-risk cardiovascular mortality showed a decrease in heart rate variability (RV) due to an increase in sympathetic activity (p=0.013). Also, in the group of patients with LVH, predictors of sudden cardiac death and arrhythmogenic substrate, were observed. The variability of the allele C1165G rs1801253 of the ADRB1 gene was associated with an increased risk (2.55-fold increase) of SCD and LVH. Also, the associations of polymorphic locus A145G (rs1801252) of the ADRB1 gene proved the presence of a permanent difference for the "risky" allele A in patients with a high risk of SCD.

CONCLUSION

Conclusions: It was set the probable association of alleles rs1801253 (C1165G) and rs1801252 (A145G) ADRB1 at the patients with a high risk of SCD compared to the control group.

Evaluation of the efficacy of signal-averaged electrocardiogram testing in the cardiac assessment of beta-thalassemia major patients

BACKGROUND

More than 70% of thalassemia's major mortality is due to the cardiac complications of this syndrome, mostly consequent to myocardial Iron overload; therefore, evaluation of such complications is of utmost importance. T2*MRI is used to assess hepatic and myocardial Iron load in thalassemia patients, which is not always available. Signal-Averaged Electrocardiography is a rather easy method of evaluating major thalassemia patients regarding their risk for sudden cardiac death.

METHODS AND MATERIALS

In this cross-sectional study, 48 patients with thalassemia major underwent evaluation with electrocardiography, signal-averaged electrocardiography, echocardiography, T2*MRI, and ferritin level. The association of the existence of ventricular late potentials in SAECG and other cardiac variables was evaluated. Moreover, the association between myocardial and hepatic Iron load and cardiac characteristics was assessed.

RESULTS

48 patients with a mean age of 30.31 ± 7.22 years old entered the study. 27 (56.3%) of the patients had ventricular late potentials, which were associated with myocardial dry Iron weight (P = 0.011). Nonspecific ST-T changes and premature atrial and ventricular contractions were seen more frequently in patients with late potentials (P = 0.002, 0.031, and 0.031, respectively). Patients with higher myocardial and hepatic Iron loads had longer QT_c in their 12-lead surface electrocardiograms.

CONCLUSION

Patients with ventricular late potentials assessed by SAECG had a higher myocardial Iron load. Higher myocardial Iron load is associated with higher cardiac complications in patients with beta-thalassemia major; therefore, SAECG can be used as a screening test for cardiac complications in beta-thalassemia major patients.

A large genome-wide association study of QT interval length utilizing electronic health records

QT interval length is an important risk factor for adverse cardiovascular outcomes; however, the genetic architecture of QT interval remains incompletely understood. We conducted a genome-wide association study of 76,995 ancestrally diverse Kaiser Permanente Northern California members enrolled in the Genetic Epidemiology Research on Adult Health and Aging cohort using 448,517 longitudinal QT interval measurements, uncovering 9 novel variants, most replicating in 40,537 individuals in the UK Biobank and Population Architecture using Genomics and Epidemiology studies. A meta-analysis of all 3 cohorts (n = 117,532) uncovered an additional 19 novel variants. Conditional analysis identified 15 additional variants, 3 of which were novel. Little, if any, difference was seen when adjusting for putative QT interval lengthening medications genome-wide. Using multiple measurements in Genetic Epidemiology Research on Adult Health and Aging increased variance explained by 163%, and we show that the ≈6 measurements in Genetic Epidemiology Research on Adult Health and Aging was equivalent to a 2.4× increase in sample size of a design with a single measurement. The array heritability was estimated at ≈17%, approximately half of our estimate of 36% from family correlations. Heritability enrichment was estimated highest and most significant in cardiovascular tissue (enrichment 7.2, 95% CI = 5.7-8.7, P = 2.1e-10), and many of the novel variants included expression quantitative trait loci in heart and other relevant tissues. Comparing our results to other cardiac function traits, it appears that QT interval has a multifactorial genetic etiology.

CLINICAL CASES OF LIFE-THREATENING ARRHYTHMIAS: LONG AND SHORT QT SYNDROMES

OBJECTIVE

The aim: To present clinical cases of sudden cardiac death in patients with prolonged and shortened QT interval.

PATIENTS AND METHODS

Materials and methods: The study includes description of two different clinical cases with prolonged and shortened QT interval after sudden cardiac death. Verification of the diagnosis was performed using the criteria recommended by the European Society of Cardiology (ESC) and European Heart Rhythm Association (EHRA).

RESULTS

Clinical case: Two clinical cases of syncopе with life-threatening arrhythmias, confirmed by electrocardiographic and clinical diagnostic criteria, indicating a change in the dispersion of the QT interval, are presented. The first case represents a patient with intermittent syncope. The patient had previously had attacks of sudden palpitations with fainting. The patient came after another episode of syncope. Further follow-up revealed clinical and electrocardiographic signs of ventricular tachycardia paroxysm. Than the prolongation of the QT interval is set. In this clinical case, verification of QT prolongation syndrome was established in the elderly. Another clinical case is associated with QT syndrome, which remains difficult to diagnose. Such cases have been described relatively recently. The clinical picture of the syndrome of short QT interval in the presented clinical case was characterized by the appearance of syncopal states. The patient showed changes in the adjusted QT interval <320 ms. The causes of syncope in a patient with a short QT interval were paroxysms of atrial fibrillation (AF) or ventricular arrhythmias. At the same time the anatomical structure of a myocardium remains normal and unchanged. The hereditary nature of the disease in the patient has been proven.

CONCLUSION

Conclusions: Timely diagnosis of prolongation (LQTS) or shortening (SQTS) of the QT interval after ECG and Holter monitoring allows you to identify a group of patients with an increased risk of developing ventricular arrhythmias, syncope and sudden cardiac death. Implantation of a cardioverter-defibrillator is an effective and safe method of preventing sudden cardiac death in patients with long and short QT syndromes.

24 h Holter ECG Monitoring of Patients with Rheumatoid Arthritis-A Potential Role for a Precise Evaluation of QT Interval Duration and Associated Arrhythmic Complications

Background: Patients with rheumatoid arthritis (RA) have increased systemic inflammatory burden associated with elevated cardiovascular mortality. Prolonged ventricular repolarisation evaluated by QT interval duration is a risk factor for cardiovascular and total mortality. In RA, mortality risk is correlated with dynamics and cumulative incidence of QTc prolongation rather than QTc value. The aim is to evaluate if QT parameters evaluated with 24 h Holter ECG are a better option to complete the cardiovascular profile of RA patients than parameters from short ECG recordings. Materials and methods: A total of 58 patients (22 males, 36 females) with RA were submitted to short ECG recordings at admission and to 24 h Holter ECG. QT interval parameters and ventricular ectopy generated from both types of recordings were analyzed. Results: QTc interval values obtained from Holter ECG were significantly higher than the values from short term ECG and were correlated with severity of inflammatory process. The number of QRS complexes with QTc > 450 ms recorded during 24 h Holter was strongly correlated with the number of ventricular events and severity of the inflammatory process. Conclusions: In patients with RA, the Holter ECG recordings could realize a more precise evaluation of the extent and dynamics of QTc interval duration and of ventricular ectopic events with potential risk of sudden death.