Malignant Arrhythmias Research Articles

PO-671-02 ELECTROCARDIOGRAPHIC CORRELATES OF PAPILLARY SCAR IN PATIENTS WITH MITRAL VALVE PROLAPSE

Mitral valve prolapse (MVP) has up to 3% prevalence in the general population and is associated with malignant arrhythmia. Late-gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) has been proposed as a risk stratification methodology. Electrocardiographic (ECG) findings that associate with LGE may provide utility for prompting CMR at initial evaluation and during follow up.

Drug-Induced QTc Prolongation: What We Know and Where We Are Going.

Drug-induced QTc prolongation is a concerning electrocardiogram (ECG) abnormality. This cardiac disturbance carries a 10% risk of sudden cardiac death due to the malignant arrhythmia, Torsades de Pointes. The Arizona Center for Education and Research on Therapeutics (AzCERT) has classified QTc prolonging therapeutic classes, such as antiarrhythmics, antipsychotics, anti-infectives, and others. AzCERT criteria categorize medications into three risk categories: "known," "possible," and "conditional risk" of QTc prolongation and Torsades de Pointes. The list of QTc prolonging medications continues to expand as new drug classes are approved and studied. Risk factors for QTc prolongation can be delineated into modifiable or non-modifiable. A validated risk scoring tool may be utilized to predict the likelihood of prolongation in patients receiving AzCERT classified medication. The resultant risk score may be applied to a clinical decision support system, which offers mitigation strategies. Mitigation strategies including discontinuation of possible offending agents with a selection of an alternative agent, assessment of potential drug interactions or dose adjustments through pharmacokinetic and pharmacodynamic monitoring, and initiation of both ECG and electrolyte monitoring are essential to prevent a drug-induced arrhythmia. The challenges presented by the COVID-19 pandemic have led to the development of innovative continuous monitoring technology, increasing protection for both patients and healthcare workers. Early intervention strategies may reduce adverse events and improve clinical outcomes in patients identified to be at risk of QTc prolongation.

Spontaneous Resolution Of Arrhythmia in Propafenone Intoxication: A Rare Case Report

Propafenone toxicity is rare but poses a life-threatening condition due to malignant arrhythmias.
 However, there is currently no recommended standard specific treatment or antidote. In our case,
 we presented a young patient with transient cardiac toxicity and spontaneous recovery in her follow
 up after taking high-dose propafenone for suicide attempt. Electrocardiography showed sinus
 rhythm with prolongation of PR interval with 240 ms, QRS width 160 ms, and corrected QT
 interval QTc with 498 ms; Terminal R wave observed in leads V1 and aVR and metabolic acidosis
 was also observed at the time of admission. In patient’s follow up, sodium bicarbonate and lipid
 emulsion treatment was planned but did not applied due to the resolution of cardiotoxic arrhythmia
 in 30 minutes after her admission, and metabolic acidemia was observed to regress with supportive
 treatment. In conclusion, propofenone intoxication, like other class 1C antiarrhythmics, is a life-
 threatening, rarely reported toxicity that complicates clinical decisions. It is critical to be aware that
 propofenone overdose can be fatal, and is also essential to remember that, despite the lack of an
 antidote, total recovery can be accomplished with constant monitoring and supportive treatment.

Metoprolol’ün Covid-19 Hastalarındaki Potansiyel Yararları

Background: We aimed to find the potential beneficial effects of metoprolol, which was added to the treatment of COVID-19 patients with drug-induced long corrected QT (di-LQTc) interval. Materials and Methods: This study was a retrospective study. Hospitalized patient files were scanned, and the data of 160 Covid-19 positive patients who were confirmed by real-time polymerase chain reaction (RT-PCR) between April 1 and June 1, 2020, were analyzed. A total of 52 patients’ data with CoVID-19 patients with di-LQTc were scanned and collected in the metoprolol group, and a total of 108 patients’ data with CoVID-19 with normal QTc levels were collected in the non-metoprolol group. Results: The mean age was 48.58±16.52 (48.75% male). The in-hospital mortality rate was 3.125% (n=5). We did not see any malignant arrhythmias in the groups during follow-up. In the metoprolol group, the peak Qtc was 466.50 (458.75-477.50) msec in patients before metoprolol treatment, whereas it decreased to 443 (428.75-453) msec at discharge. Forward conditional logistic regression analysis demonstrated that basal C-reactive protein (CRP) (OR=1.031, 95%CI: 1.001-1.062, p=0.043) was the independent predictor of di-LQTc in Covid-19 patients. Conclusion: COVID-19 patients with di-LQTc could be treated and we thought we could reverse the QT prolongation by adding metoprolol to the treatment protocol.

QTc prolongation in adolescents with acute alcohol intoxication

In adults, alcohol intoxication is associated with prolongation of the QT interval corrected for heart rate (QTc). The QTc is influenced by age and sex. Although alcohol intoxication is increasingly common in adolescents, there are no data on the prevalence of QTc prolongation in adolescents with alcohol intoxication. This study aimed to determine the prevalence of QTc prolongation in adolescents with alcohol intoxication and identify at-risk adolescents. In this observational study including adolescents aged 10–18 years, heart rate and QT interval were automatically assessed from an electrocardiogram (ECG) at alcohol intoxication using a validated algorithm. The QTc was calculated using both the Bazett formula (QTcB) and Fridericia formula (QTcF). If present, an ECG recorded within 1 year of the date of admission to the emergency department was obtained as a reference ECG. A total of 317 adolescents were included; 13.3% had a QTcB and 7.9% a QTcF longer than the sex- and age-specific 95th-percentile. None of the adolescents had a QTcB or QTcF > 500 ms, but 11.8% of the adolescents with a reference ECG had a QTcB prolongation of > 60 ms, while no adolescents had a QTcF prolongation of > 60 ms. QTc prolongation was mainly attributable to an increase in heart rate rather than QT prolongation, which underlies the differences between QTcB and QTcF. Male sex and hypokalaemia increased the likelihood of QTc prolongation.Conclusion: QTc prolongation was seen in approximately 10% of the adolescents presenting with alcohol intoxication, and although no ventricular arrhythmias were observed in this cohort, QTc prolongation increases the potential for malignant QT-related arrhythmias. Clinicians must be aware of the possibility of QTc prolongation during alcohol intoxication and make an effort to obtain an ECG at presentation, measure the QT interval, and give an adequate assessment of the findings. We advocate admitting adolescents with alcohol intoxication and QTc prolongation. During hospital admission, we recommend limiting exposure to QTc-prolonging medication, increasing potassium levels to a high-normal range (4.5–5.0 mmol/L) and obtaining a reference ECG at discharge.What is Known:• One out of five deaths in adolescents is alcohol-related. Alcohol intoxication has been related to cardiac arrhythmias and sudden cardiac death.•In adults, alcohol intoxication is associated with QTc prolongation.What is New:•Approximately 10% of the adolescents with alcohol intoxication had a QTc longer than the age- and sexspecific cut-off. In contrast to adults, in adolescents with alcohol intoxication, QTc prolongation is attributable to an increase in heart rate, rather than a prolongation of the QT interval.•Especially males and adolescents with hypokalaemia are at risk of QTc prolongation.

A very rare cause of sudden cardiac arrest in children: triadin knockout syndrome.

A 7.5-year-old male patient was referred to our clinic with a history of recurrent syncope and aborted cardiac arrest. There was no family history of sudden death, syncope, or arrhythmia. Physical examination, electrocardiography, echocardiography, and 24-hour rhythm Holter monitoring were normal, and bidirectional ventricular tachycardiaT was detected during the exercise stress test. Genetic analysis revealed a homozygous mutation of c.531_533delinsGG, p.(Lys179Asnfs * 44) frameshift variant in TRDN(NM_006073) gene. A 4.5-year-old male was admitted due to syncope during exertion and underwent cardiopulmonary resuscitation due to sudden cardiac arrest. He had family history about sudden cardiac death. Physical examination was normal, and there was borderline QTc prolongation. Bidirectional non-sustained polymorphic ventricular tachycardia was observed at adrenaline provocation test. In genetic analysis, c.568dupA, pII190Asnfs * 2 frameshift variant homozygous mutation was detected in TRDN(NM_006073) gene. Intracardiac defibrillator implantation were performed for both cases. There has not been any event under propranolol and flecainide combination treatment. Triadin knockout syndrome (TCOS) is a rare overlap syndrome characterized by highly malignant arrhythmias, and it is a deadly combination of long QT syndrome and catecholaminergic polymorphic ventricular tachycardia that affects primarily young children. Since lethal arrhythmias are frequently described, genetic testing is very important in these patients. Because, identification of a genetic mutation may be a guide in treatment.

A Comprehensive Assessment of Cardiomyopathies through Cardiovascular Magnetic Resonance: Focus on the Pediatric Population.

Cardiomyopathies (CMPs) are a heterogeneous group of diseases that involve the myocardium and result in systolic or diastolic impairment of the cardiac muscle, potentially leading to heart failure, malignant arrhythmias, or sudden cardiac death. Occurrence in pediatric age is rare but has been associated with worse outcomes. Non-invasive cardiac imaging techniques, integrated with clinical, genetic, and electrocardiographic data, have shown a pivotal role in the clinical work-up of such diseases by defining structural alterations and assessing potential complications. Above all modalities, cardiovascular magnetic resonance (CMR) has emerged as a powerful tool complementary to echocardiography to confirm diagnosis, provide prognostic information and guide therapeutic strategies secondary to its high spatial and temporal resolution, lack of ionizing radiation, and good reproducibility. Moreover, CMR can provide in vivo tissue characterization of the myocardial tissue aiding the identification of structural pathologic changes such as replacement or diffuse fibrosis, which are predictors of worse outcomes. Large prospective randomized studies are needed for further validation of CMR in the context of childhood CMPs. This review aims to highlight the role of advanced imaging with CMR in CMPs with particular reference to the dilated, hypertrophic and non-compacted phenotypes, which are more commonly seen in children.

β-blocker adherence among patients with congenital long QT syndrome: a nationwide study.

β-blockers are the first line of treatment in patients with congenital long QT syndrome (cLQTS) (class I or II recommendation) in order to prevent malignant arrhythmias. Hence, we examined long-term β-blocker adherence and associated risk factors among patients with cLQTS. Danish patients with cLQTS claiming a prescription for any β-blocker after their cLQTS diagnosis were identified using data from nationwide registries and specialized inherited cardiac disease clinics (1995-2017). Patients were followed for up to 5 years. Treatment breaks >60days were assessed (i.e. proxy for reduced adherence). Multivariable Cox regression was used to identify risk factors associated with breaks of >60 days in β-blocker treatment. Overall, 500 out of 633 (79%) patients with cLQTS claimed at least one prescription for any β-blocker after cLQTS diagnosis. During follow-up, 38.4% had a treatment break. Risk factors significantly associated with treatment breaks were implantable cardioverter defibrillator (ICD) [hazard ratio (HR) = 1.65, 95% confidence interval (CI): 1.08-2.53], β-blocker side effects (HR=2.69, 95% CI: 1.75-4.13), and psychiatric disease (HR=1.63, 95% CI: 1.04-2.57). In contrast, patients presenting with ventricular tachycardia/syncope as cLQTS disease manifestation were less likely to have a treatment break compared with asymptomatic patients (HR=0.55, 95% CI: 0.33-0.92). Reduced β-blocker adherence was common with more than a third of patients having a treatment break >60days after cLQTS diagnosis. Patients with psychiatric disease, self-reported β-blocker side effects, and an ICD were more likely to display reduced adherence, whereas a severe cLQTS disease manifestation was associated with optimal β-blocker adherence.

Admission hyperglycemia in acute myocardial infarction is associated with an increased risk of arrhythmias: A systematic review and meta-analysis.

BackgroundAdmission hyperglycemia (AH) has shown to be associated with higher mortality rates in acute myocardial infarction (AMI). Malignant arrhythmia is one of the causes of death in AMI; however, it is unclear whether AH is associated with an increased arrhythmia risk. We conducted this systematic review and meta‐analysis to assess the association between AH and arrhythmias in AMI.MethodsWe searched MEDLINE, and Embase databases from inception to September 2021 to identify studies that compared arrhythmia rates between AMI patients with AH and those without. Arrhythmias of interest included ventricular tachyarrhythmias (VA), atrial fibrillation (AF), and atrioventricular block.ResultsThirteen cohort studies with a total of 12,898 patients were included. AH was associated with a higher risk of overall arrhythmias (18% vs 10.3%, pooled odds ratio [OR] = 1.89, 95% confidence interval [CI]: 1.39–2.56, P < .001), VA (16.4% vs 11.1%, pooled OR = 1.56, 95% CI: 1.11–2.18, P = .01), and new onset AF (17.8% vs 6.4%, pooled OR = 2.13, 95% CI: 1.4–3.25, P < .0010. Subgroup analysis of diabetes status regarding overall arrhythmias showed that the increased risk of arrhythmias in the AH group was consistent in both patients with a history of diabetes (18% vs 12.5%, pooled OR = 2.33, 95%CI: 1.2–4.52, P = .004) and without (15.7%. vs 9% pooled OR = 1.35, 95% CI: 1.1–1.66, P = .013).ConclusionAdmission hyperglycemia in AMI was associated with the increased risk of arrhythmias, regardless of history of diabetes mellitus.

Assessment of Exhaustive Exercise under Internet of Things Exercise Monitoring System and Mechanism Analysis of Cardiovascular Endothelial Cell Apoptosis Induced by Oxidative Stress

To investigate the effect of high-intensity exhaustive exercise on body and the molecular mechanism of oxidative stress regulating apoptosis of cardiovascular endothelial cells (CVECs), 70 college students who took an aerobics course were recruited as the research subjects, all of which were divided into the high-intensity group (35 students) and the moderate-intensity group (35 students). The Internet of Things- (IoT-) based human exercise information monitoring system was employed to collect the electrocardiogram, serum indexes, and oxidative stress indexes of the two groups of subjects after exercise. Moreover, 30 clean male SD rats were divided into exhaustive exercise group ( n = 10 ), routine exercise group ( n = 10 ), and blank control group ( n = 10 ) using treadmill exercise as stress source, and various physiological indexes of the three groups were compared. In human experiments, the time-domain indexes of heart rate variability (HRV), 50 ms in the total number of sinus heartbeats (PNN50), the standard deviation of all NN intervals (SDNN), standard deviation of mean NN interval (SDANN), standard deviation of difference between adjacent NN intervals (SDSD), root mean square (RMSSD) in the high intensity group were lower than those in the moderate intensity group ( P &lt; 0.05 ). The levels of T-sensitive troponin I (Tnl-ultra), cortisol (COR), high-sensitive troponin T (TnT-hs), high-sensitive C-reactive protein (hs-CRP), and human heart-type fatty acid binding protein (HUMAN H-FABP) in high intensity group were higher than those in moderate intensity group ( P &lt; 0.05 ). Experiments on animals found that SOD content and mRNA expression of fork-head box 03A (FOX03A) and silencing-information regulator 1 (Sirtl) in serum of rats in exhaustion exercise group were lower than those in the routine exercise group and blank control group, while lactate dehydrogenase (LDH) and malondialdehyde (MDA) contents were opposite ( P &lt; 0.05 ). In short, strenuous exercise made the body in the state of acute stress, leading to the disturbance of cardiac autonomic nervous function and sympathetic nervous function, and increasing the risk of malignant arrhythmia. Oxidative stress induced by exhaustive exercise may promote the apoptosis of CVECs by reducing the expression of Sirtl and FOX03A and locating FOX03A to the nucleus.

Evaluation of Cardiac Electrophysiological Balance in Patients with Subclinical Hypothyroidism

Introduction: Subclinical hypothyroidism (SH) is defined by slightly elevated thyroid-stimulating hormone (TSH) levels with normal free triiodothyronine (fT3) and thyroxine (fT4) levels. SH is related to cardiovascular events, including malignant arrhythmias. Cardiac electrophysiological balance (iCEB) and its corrected form with heart rate (iCEBc) are useful electrocardiographic (ECG) parameters for the prediction of malign arrhythmias. In this study, we aimed to evaluate iCEB and iCEBc in SH patients. Patients and Methods: A total of 164 patients (n= 82 patients with SH and n= 82 controls) were enrolled in this study. iCEB was calculated by dividing QT by QRS, and iCEBc was calculated by dividing corrected QT (QTc) by QRS. The groups were compared based on ECG parameters. Correlation and multiple linear regression analyses were used to assess the association of ECG parameters with TSH levels. Results: There were no differences between the groups regarding clinical and laboratory findings. Tp-e, QT, QTc, Tp-e/QT, Tp-e/QTc, iCEB, and iCEBc were significantly prolonged in SH patients compared to controls. In correlation analyses, all of the abovementioned ECG parameters were significantly correlated with serum TSH levels. Multiple linear regression analysis indicated that Tp-e, iCEB, and iCEBc were independently associated with serum TSH levels in SH patients. Conclusion: To our knowledge, this was the first study to demonstrate that iCEB and iCEBc were both prolonged in SH patients compared to controls, and both of them were independently correlated with TSH levels in such patients.

When Should the Sternum Be Closed After Aortic Surgery?

Introduction: There are many factors affecting postoperative morbidity and mortality in patients managed with delayed sternal closure (DSC) after aortic surgery. This study aimed to examine the postoperative management of patients after DSC and the factors affecting morbidity and mortality. Patients and Methods: Among 2151 patients who underwent ascending aorta and/or aortic valve surgery between January 2012 and December 2020, 64 patients managed with DSC were included in the study. The records of the patients were obtained from the hospital archive/hospital electronic database. Postoperative day 30 was determined as early mortality. Results: Uncontrollable bleeding 34.4% (n= 22), LCOS (Low Cardiac Output Syndrome) 31.4% (n= 20) and mediastinal edema 28.1% (n= 18)were the main causes for DSC. In the remaining patients (6.3%, n= 4), DSC was preferred for other non-specific reasons such as uncontrollable arrhythmia. Forty-five patients’ chests (70.3%) were closed in the postoperative period, and 19 patients (29.7%) could not be closed due to death (p&lt; 0.001). Early mortality was observed in 27 patients (42.2%), and sepsis was observed in 10 patients (15.6%). Deep sternal wound infection (DSWI) was present in 4.7% of the patients and the rate of sepsis was higher in this patient group (66.7%-13.1%, p&lt; 0.05). There was no statistically significant difference in the probability of sepsis in the culture-positive patient group (p&gt; 0.05). However, the closure time was longer in patients with a previous operation history, postoperative acute renal failure, surgical site infection, and postoperative bleeding revision/surgical revision (p&lt; 0.05). Conclusion: DSC can be preferred as a life-saving method for various reasons such as bleeding diathesis, mediastinal edema, and malignant arrhythmia after open-heart surgery. Accurate timing and close follow-up are important for sternal closure. In these patients, a multidisciplinary approach is required in the postoperative period.

Arrhythmogenic Mitral Valve Prolapse.

Mitral valve prolapse (MVP) is a common condition present in 1–3% of the population. There has been evidence that a subset of MVP patients is at higher risk of sudden cardiac death. The arrhythmogenic mechanism is related to fibrotic changes in the papillary muscles caused by the prolapsing valve. ECG features include ST-segment depression, T wave inversion or biphasic T waves in inferior leads, and premature ventricular contractions arising from the papillary muscles and the fascicular system. Echocardiography can identify MVP and mitral annular disjunction, a feature that has significant negative prognostic value in MVP. Cardiac MRI is indicated for identifying fibrosis. Patients with high-risk features should be referred for further evaluation. Catheter ablation and mitral valve repair might reduce the risk of malignant arrhythmia. MVP patients with high-risk features and clinically documented ventricular arrhythmia may also be considered for an ICD.

Altered Cardiac Repolarization in Chronic Obstructive Pulmonary Disease.

OBJECTIVEAltered cardiac repolarization is an important mechanism in the development of malignant cardiac arrhythmia and in the occurrence of sudden cardiac death. It is known that the risk of cardiac arrhythmia and sudden death is increased in patients with chronic obstructive pulmonary disease. Evaluating the measurements of repolarization in the electrocardiogram may provide useful information to determine potential risks for lethal arrhythmias in the patients with chronic obstructive pulmonary disease. In the present study, we investigated the possible relationships between repolarization parameters in the electrocardio and demographic, clinical, and biochemical findings in patients with chronic obstructive pulmonary disease.MATERIAL AND METHODS: In the present study, 35 patients with Global Initiative for Chronic Obstructive Lung Disease A-B constituted group 1 and 35 patients with Global Initiative for Chronic Obstructive Lung Disease C-D constituted group 2. Cardiac repolarization and dispersion (QTc interval and QT dispersion) were measured on 12-lead electrocardiogram. QTc interval, QT dispersion, TP-e, and Tp-e/QTc were evaluated in order to determine the patients at risk of sudden cardiac death. QTc interval >440 ms in men and >460 ms in women was considered as prolonged QTc interval.RESULTS: QTc and QTd values were found to be statistically significantly prolonged in the group of GOLD C-D compared to the group of GOLD A-B (P < .001). QTc value showed negative correlation with the ratio of forced expiratory volume in 1 second to forced vital capacity and partial pressure of oxygen (P = .030, r = −0.260; P = .006, r = −0.332, respectively). No significant difference was in Tp-e and Tp-e/QTc between the groups (P = .73, P = .12, respectively).CONCLUSION: QTc and QTd are non-invasive markers reflecting arrhythmogenicity, and our findings were found to be related to prolonged QTc and QTd in patients with chronic obstructive pulmonary disease. Prolongation in the dispersion of repolarization and altered cardiac repolarization in the population with chronic obstructive pulmonary disease may be related to hypoxemia and airway obstruction. Alterations in the cardiac repolarization may put these patients at high risk for malignant ventricular arrhythmia and sudden cardiac death.

Protein Kinase C-Mediated Hyperphosphorylation and Lateralization of Connexin 43 Are Involved in Autoimmune Myocarditis-Induced Prolongation of QRS Complex.

Myocarditis is a serious and potentially life-threatening disease, which leads to cardiac dysfunction and sudden cardiac death. An increasing number of evidence suggests that myocarditis is also a malignant complication of coronavirus pneumonia, associated with heart failure and sudden cardiac death. Prolonged QRS complexes that are related to malignant arrhythmias caused by myocarditis significantly increase the risk of sudden cardiac death in patients. However, the molecular mechanisms are not fully known at present. In this study, we identify protein kinase C (PKC) as a new regulator of the QRS complex. In isolated hearts of normal rats, the PKC agonist, phorbol-12-myristate-13-acetate (PMA), induced prolongation of the QRS complex. Mechanistically, hyperphosphorylation and lateralization of connexin 43 (Cx43) by PKC induced depolymerization and internalization of Cx43 gap junction channels and prolongation of the QRS duration. Conversely, administration of the PKC inhibitor, Ro-32-0432, in experimental autoimmune myocarditis (EAM) rats after the most severe inflammation period still significantly rescued the stability of the Cx43 gap junction and alleviated prolongation of the QRS complex. Ro-32-0432 reduced phosphorylation and blocked translocation of Cx43 in EAM rat heart but did not regulate the mRNA expression level of ventricular ion channels and the other regulatory proteins, which indicates that the inhibition of PKC might have no protective effect on ion channels that generate ventricular action potential in EAM rats. These results suggest that the pharmacological inhibition of PKC ameliorates the prolongation of the QRS complex via suppression of Cx43 hyperphosphorylation, lateralization, and depolymerization of Cx43 gap junction channels in EAM rats, which provides a potential therapeutic strategy for myocarditis-induced arrhythmias.

The Arrhythmogenic Face of COVID-19: Brugada ECG Pattern in SARS-CoV-2 Infection.

In 1992, Brugada syndrome (BS) was first described; an often unrecognized cardiac conduction disorder mainly associated with unexplained sudden cardiac arrest and consecutive syncope. Nevertheless, the pathomechanism of BS and sudden cardiac death remains mainly explained. Mutations in the cardiac sodium channels, which cause a reduction or functional loss of these channels, are associated with characteristic electrocardiographic (ECG) abnormalities and malignant arrhythmia. The majority of affected people are previously healthy and unaware of their genetic predisposition for BS and might experience ventricular tachyarrhythmias and cardiac arrest potentially triggered by several factors (e.g., alcohol, sodium channel blockers, psychotropic drugs, and fever). Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was firstly identified in Wuhan in early December 2019 and rapidly spread worldwide as coronavirus disease (COVID-19). COVID-19 is typically characterized by a severe inflammatory response, activation of the immune system, and high febrile illness. Due to this condition, symptomatic COVID-19 infection or vaccination might serve as inciting factor for unmasking the Brugada pattern and represents a risk factor for developing proarrhythmic complications. The aim of this narrative review was to detail the association between virus-related issues such as fever, electrolyte disturbance, and inflammatory stress of COVID-19 infection with transient Brugada-like symptoms and ECG-pattern and its susceptibility to proarrhythmogenic episodes.

Role of Scar and Border Zone Geometry on the Genesis and Maintenance of Re-Entrant Ventricular Tachycardia in Patients With Previous Myocardial Infarction.

In patients with healed myocardial infarction, the left ventricular ejection fraction is characterized by low sensitivity and specificity in the prediction of future malignant arrhythmias. Thus, there is the need for new parameters in daily practice to perform arrhythmic risk stratification. The aim of this study is to identify some features of proarrhythmic geometric configurations of scars and border zones (BZ), by means of numerical simulations based on left ventricular models derived from post myocardial infarction patients. Two patients with similar clinical characteristics were included in this study. Both patients exhibited left ventricular scars characterized by subendo- and subepicardial BZ and a transmural BZ isthmus. The scar of patient #1 was significantly larger than that of patient #2, whereas the transmural BZ isthmus and the subdendo- and subepicardial BZs of patient #2 were thicker than those of patient #1. Patient #1 was positive at electrophysiologic testing, whereas patient #2 was negative. Based on the cardiac magnetic resonance (CMR) data, we developed a geometric model of the left ventricles of the two patients, taking into account the position, extent, and topological features of scars and BZ. The numerical simulations were based on the anisotropic monodomain model of electrocardiology. In the model of patient #1, sustained ventricular tachycardia (VT) was inducible by an S2 stimulus delivered at any of the six stimulation sites considered, while in the model of patient #2 we were not able to induce sustained VT. In the model of patient #1, making the subendo- and subepicardial BZs as thick as those of patient #2 did not affect the inducibility and maintenance of VT. On the other hand, in the model of patient #2, making the subendo- and subepicardial BZs as thin as those of patient #1 yielded sustained VT. In conclusion, the results show that the numerical simulations have an effective predictive capability in discriminating patients at high arrhythmic risk. The extent of the infarct scar and the presence of transmural BZ isthmuses and thin subendo- and subepicardial BZs promote sustained VT.

Sympathectomy is Back. Again

Left ventricular assist devices (LVADs) undoubtedly save lives and improve quality of life, but they are still vulnerable to malignant arrhythmias. While most LVAD recipients will tolerate ventricular tachycardia (VT) and even fibrillation for surprisingly long periods of time, it is not sustainable for any clinically relevant period. In fact, most will not tolerate this rhythm for more than a few hours.

Circulating linoleic acid at the time of myocardial infarction and risk of primary ventricular fibrillation

Primary ventricular fibrillation (PVF) is a major driver of cardiac arrest in the acute phase of ST-segment elevation myocardial infarction (STEMI). Enrichment of cardiomyocyte plasma membranes with dietary polyunsaturated fatty acids (PUFA) reduces vulnerability to PVF experimentally, but clinical data are scarce. PUFA status in serum phospholipids is a valid surrogate biomarker of PUFA status in cardiomyocytes within a wide range of dietary PUFA. In this nested case–control study (n = 58 cases of STEMI-driven PVF, n = 116 control non-PVF STEMI patients matched for age, sex, smoking status, dyslipidemia, diabetes mellitus and hypertension) we determined fatty acids in serum phospholipids by gas-chromatography, and assessed differences between cases and controls, applying the Benjamini–Hochberg procedure on nominal P-values to control the false discovery rate (FDR). Significant differences between cases and controls were restricted to linoleic acid (LA), with PVF patients showing a lower level (nominal P = 0.002; FDR-corrected P = 0.027). In a conditional logistic regression model, each one standard deviation increase in the proportion of LA was related to a 42% lower prevalence of PVF (odds ratio = 0.58; 95% confidence interval, 0.37, 0.90; P = 0.02). The association lasted after the inclusion of confounders. Thus, regular consumption of LA-rich foods (nuts, oils from seeds) may protect against ischemia-driven malignant arrhythmias.

Effect and influence factors of cardiopulmonary resuscitation in children with congenital heart disease in pediatric intensive care unit

Objective: To investigate the prognostic factors of children with congenital heart disease (CHD) who had undergone cardiopulmonary resuscitation (CPR) in pediatric intensive care unit (PICU) in China. Methods: From November 2017 to October 2018, this retrospective multi-center study was conducted in 11 hospitals in China. It contained data from 281 cases who had undergone CPR and all of the subjects were divided into CHD group and non-CHD group. The general condition, duration of CPR, epinephrine doses during resuscitation, recovery of spontaneous circulation (ROSC), discharge survival rate and pediatric cerebral performance category in viable children at discharge were compared. According to whether malignant arrhythmia is the direct cause of cardiopulmonary arrest or not, children in CHD and non-CHD groups were divided into 2 subgroups: arrhythmia and non-arrhythmia, and the ROSC and survival rate to discharge were compared. Data in both groups were analyzed by t-test, chi-square analysis or ANOVA, and logistic regression were used to analyze the prognostic factors for ROSC and survival to discharge after cardiac arrest (CA). Results: The incidence of CA in PICU was 3.2% (372/11 588), and the implementation rate of CPR was 75.5% (281/372). There were 144 males and 137 females with median age of 32.8 (5.6, 42.7) months in all 281 CPA cases who received CPR. CHD group had 56 cases while non-CHD had 225 cases, with the percentage of 19.9% (56/281) and 80.1% (225/281) respectively. The proportion of female in CHD group was 60.7% (34/56) which was higher than that in non-CHD group (45.8%, 103/225) (χ2=4.00, P=0.045). There were no differences in ROSC and rate of survival to discharge between the two groups (P>0.05). The ROSC rate of children with arthythmid in CHD group was 70.0% (28/40), higher than 6/16 for non-arrhythmic children (χ2=5.06, P=0.024). At discharge, the pediatric cerebral performance category scores (1-3 scores) of CHD and non-CHD child were 50.9% (26/51) and 44.9% (92/205) respectively. Logistic regression analysis indicated that the independent prognostic factors of ROSC and survival to discharge in children with CHD were CPR duration (odds ratio (OR)=0.95, 0.97; 95%CI: 0.92~0.97, 0.95~0.99; both P<0.05) and epinephrine dosage (OR=0.87 and 0.79, 95%CI: 0.76-1.00 and 0.69-0.89, respectively; both P<0.05). Conclusions: There is no difference between CHD and non-CHD children in ROSC and survival rate of survival to discharge was low. The epinephrine dosage and the duration of CPR are related to the ROSC and survival to discharge of children with CHD.