Incidence and Predictors for Recurrence of Ventricular Arrhythmia Presenting During Acute Myocarditis: A Multicenter Study

BACKGROUND

Management of acute myocarditis (AM) patients experiencing ventricular arrhythmia (VA) during acute illness is controversial, especially regarding early implantable cardioverter-defibrillator (ICD) implantation.

OBJECTIVES

The purpose of this study was to evaluate the prevalence of and find predictors for long-term sustained VA recurrence and overall mortality among AM patients with VA.

METHODS

This was a multicenter retrospective analysis of AM patients (verified by cardiac magnetic resonance imaging or myocardial biopsy) with documented VA during the acute illness ("initial VA"). Patients with history of myocardial infarction, heart failure, or VA were excluded. The study endpoint was a composite of sustained VA and overall mortality during follow-up.

RESULTS

The study included 69 AM patients with initial VA: sustained monomorphic ventricular tachycardia (MMVT) (n = 25), sustained polymorphic ventricular tachycardia (VT)/ventricular fibrillation (n = 13), and nonsustained VT (n = 31). Age was 44 ± 13 years, and 23 of 69 (33.3%) were women. During median follow-up of 5.5 years, 27 of 69 (39%) patients reached the composite endpoint including sustained VA (n = 24) and death (n = 11). Initial MMVT, predischarge left ventricular dysfunction (left ventricular ejection fraction <50%), and anteroseptal delayed enhancement on cardiac magnetic resonance imaging were significantly associated with the composite endpoint. On multivariable analysis, initial MMVT (HR: 5.17; 95% CI: 1.81-14.6; P = 0.001) and predischarge LV dysfunction (HR: 4.57; 95% CI: 1.83-11.5; P = 0.005) were independently associated with the composite endpoint. Using these 2 predictors, we could delineate subgroups with low (∼4%), medium (∼42%), and high (∼82%) 10-year incidence of composite endpoint.

CONCLUSIONS

AM patients presenting with VA have high incidence of sustained VA recurrence and mortality posthospitalization. Initial MMVT and predischarge LV dysfunction are independently associated with VA recurrence and mortality. Implantable cardioverter-defibrillator implantation may be considered in such high-risk patients.

Cardiac arrhythmia in individuals with steroid sulfatase deficiency (X-linked ichthyosis): candidate anatomical and biochemical pathways

Circulating steroids, including sex hormones, can affect cardiac development and function. In mammals, steroid sulfatase (STS) is the enzyme solely responsible for cleaving sulfate groups from various steroid molecules, thereby altering their activity and water solubility. Recent studies have indicated that Xp22.31 genetic deletions encompassing STS (associated with the rare dermatological condition X-linked ichthyosis), and common variants within the STS gene, are associated with a markedly elevated risk of cardiac arrhythmias, notably atrial fibrillation/flutter. Here, we consider emerging basic science and clinical findings which implicate structural heart abnormalities (notably septal defects) as a mediator of this heightened risk, and propose candidate cellular and biochemical mechanisms. Finally, we consider how the biological link between STS activity and heart structure/function might be investigated further and the clinical implications of work in this area.

Better Late Than Never: Definitive Anatomic Repair of Dextro-Transposition of the Great Arteries

We present a case of anatomic repair of dextro-transposition of the great arteries (d-TGA) with ventricular septal defect (VSD) in a 55-year-old man who presented with acute heart failure. This case highlights the importance of multimodal imaging and multidisciplinary involvement in developing a comprehensive surgical and medical plan for adults with congenital heart disease. We think this is the oldest reported patient undergoing anatomic surgical repair of d-TGA with VSD.

Evaluation of patients with implantable cardioverter-defibrillator in a Latin American tertiary center

INTRODUCTION

Despite advancements in implantable cardioverter-defibrillator (ICD) technology, sudden cardiac death (SCD) remains a persistent public health concern. Chagas disease (ChD), prevalent in Brazil, is associated with increased ventricular tachycardia (VT) and ventricular fibrillation (VF) events and SCD compared to other cardiomyopathies.

METHODS

This retrospective observational study included patients who received ICDs between October 2007 and December 2018. The study aims to assess whether mortality and VT/VF events decreased in patients who received ICDs during different time periods (2007-2010, 2011-2014, and 2015-2018). Additionally, it seeks to compare the prognosis of ChD patients with non-ChD patients. Time periods were chosen based on the establishment of the Arrhythmia Service in 2011. The primary outcome was overall mortality, assessed across the entire sample and the three periods. Secondary outcomes included VT/VF events and the combined outcome of death or VT/VF.

RESULTS

Of the 885 patients included, 31% had ChD. Among them, 28% died, 14% had VT/VF events, and 37% experienced death and/or VT/VF. Analysis revealed that period 3 (2015-2018) was associated with better death-free survival (p = .007). ChD was the only variable associated with a higher rate of VT/VF events (p < .001) and the combined outcome (p = .009).

CONCLUSION

Mortality and combined outcome rates decreased gradually for ICD patients during the periods 2011-2014 and 2015-2018 compared to the initial period (2007-2010). ChD was associated with higher VT/VF events in ICD patients, only in the first two periods.

Smoking-associated Electrocardiographic Abnormalities Predict Cardiovascular Mortality: Insights from NHANES

Background—

Smoking is associated with arrhythmia and sudden cardiac death, but the biological mechanisms remain unclear. Abnormal electrocardiogram (ECG) durations of ventricular repolarization (QT interval), atrial depolarization (P wave), and atrioventricular depolarization (PR interval and segment), predict cardiac arrhythmia and mortality.

Objectives—

To elucidate how smoking affects cardiac excitation, we assessed in a nationally representative sample (NHANES III) associations between cotinine, abnormalities in P duration, PR interval, PR segment, rate-corrected QT (QTc), QRS duration, and JT interval, and long-term mortality.

Methods—

We analyzed data from 5,633 adults using survey-weighted multinomial logistic regression to estimate associations between tobacco use (>15 ng/ml serum cotinine) and short (<5th percentile) or long (>95th percentile) ECG intervals, relative to reference (5 - 95th percentile).

Results—

After adjustment for demographics, risk factors, and conduction-altering medications, smoking was associated with a higher odds of short PR interval, PR segment, and QRS, and long JT. Broader ECG effects of smoking were also assessed by survey-weighted linear regression of continuous cotinine and ECG intervals, which revealed cotinine inversely associated with PR segment and QTc. Over a 22-year follow-up, many ECG abnormalities predicted cardiovascular mortality in smokers, including long JT, QRS, and QTc, and short QRS.

Conclusions—

Smoking increases likelihood for rapid atrioventricular conduction, rapid ventricular depolarization, and slow ventricular repolarization. The ventricular electrophysiologic abnormalities associated with smoking also predict cardiovascular mortality in smokers; however, traditional ECG measures of cardiac risk like QTc can overlook these ventricular defects and their independent predictive value in smokers.

Intracranial leptomeningeal CNS ganglioneuroblastoma. First report and review of the literature

BACKGROUND

CNS ganglioneuroblastoma in an extremely rare embryonal tumour, specifically in the pediatric population. Bad prognosis is documented due to aggressiveness and absence of protocolized treatment at the moment.

CLINICAL DESCRIPTION

We present the case of a 5-year-old boy who presented with sudden loss of consciousness. CT scan was performed showing a large posterior fossa lesion with several intraventricular focal lesions, suggesting metastases, the largest one located inside the III ventricle. The patient underwent a posterior fossa resection of the lesion and a subtotal resection of the III ventricle lesion, with adjuvant chemotherapy. The evolution was poor and the patient finally died 3 months after diagnosis.

CONCLUSION

Ganglioneuroblastoma is extremely likely to recur quickly and extensively. There is little knowledge about treatment options but is documented that gross total resection followed by adjuvant radiotherapy and chemotherapy is the best management in these patients.

Store-Operated Calcium Entry Increases Nuclear Calcium in Adult Rat Atrial and Ventricular Cardiomyocytes

Store-operated calcium entry (SOCE) in cardiomyocytes may be involved in cardiac remodeling, but the underlying mechanisms remain elusive. We hypothesized that SOCE may increase nuclear calcium, which alters gene expression via calcium/calmodulin-dependent enzyme signaling, and elucidated the underlying cellular mechanisms. An experimental protocol was established in isolated adult rat cardiomyocytes to elicit SOCE by re-addition of calcium following complete depletion of sarcoplasmic reticulum (SR) calcium and to quantify SOCE in relation to the electrically stimulated calcium transient (CaT) measured in the same cell before SR depletion. Using confocal imaging, calcium changes were recorded simultaneously in the cytosol and in the nucleus of the cell. In ventricular myocytes, SOCE was observed in the cytosol and nucleus amounting to ≈15% and ≈25% of the respective CaT. There was a linear correlation between the SOCE-mediated calcium increase in the cytosol and nucleus. Inhibitors of TRPC or Orai channels reduced SOCE by ≈33-67%, whereas detubulation did not. In atrial myocytes, SOCE with similar characteristics was observed in the cytosol and nucleus. However, the SOCE amplitudes in atrial myocytes were ≈two-fold larger than in ventricular myocytes, and this was associated with ≈1.4- to 3.6-fold larger expression of putative SOCE proteins (TRPC1, 3, 6, and STIM1) in atrial tissue. The results indicated that SOCE in atrial and ventricular myocytes is able to cause robust calcium increases in the nucleus and that both TRPC and Orai channels may contribute to SOCE in adult cardiomyocytes.

Investigation of the cardiac effects of exercise testing on apparently healthy Boxer dogs

BACKGROUND

Holter electrocardiographic monitoring is a cornerstone of diagnostic testing for arrhythmogenic cardiomyopathy (ACM) in Boxer dogs, but physical activity during monitoring is not controlled. In humans, exercise testing (ExT) can identify latent tachyarrhythmias associated with cardiomyopathy, and exercise increases serum cardiac troponin-I concentrations ([hs-cTnI]). These effects have not yet been investigated in Boxer dogs.

HYPOTHESIS/OBJECTIVES

Subjecting Boxer dogs to brief, moderate-intensity ExT can identify changes in Holter recordings and [hs-cTnI] compared to baseline results.

ANIMALS

Thirty overtly healthy, client-owned Boxer dogs.

METHODS

Prospective interventional study. Dogs underwent baseline diagnostic testing including 24-hour Holter monitoring and [hs-cTnI], followed by brief ExT (accompanied, brisk stair-climbing and -descending for <5 minutes).

RESULTS

Eleven dogs (37%) had >100 premature ventricular complexes (PVCs)/24 hours at baseline (3), ExT (3), or both (5). After ExT, these dogs had more PVCs/24 hours and greater increases in [hs-cTnI] compared to those with ≤100 PVCs/24 hours. Dogs with the striatin mutation had more PVCs/24 hours and a greater increase in [hs-cTnI] after ExT than did dogs without the striatin mutation.

CONCLUSIONS AND CLINICAL IMPORTANCE

Exercise testing may improve the binary classification of Boxer dogs with or without ACM by increasing the number of PVCs and [hs-cTnI] in affected dogs to a greater degree than in unaffected dogs. This effect also is associated with presence or absence of the striatin mutation. Exercise should be a controlled variable when screening Boxer dogs for ACM.

Arrhythmia and Survival Outcomes Among Black Patients and White Patients With a Primary Prevention Defibrillator

BACKGROUND

Black Americans have a higher risk of nonischemic cardiomyopathy (NICM) than White Americans. We aimed to evaluate differences in the risk of tachyarrhythmias among patients with an implantable cardioverter-defibrillator (ICD).

METHODS

The study population comprised 3895 ICD recipients in the United States enrolled in primary prevention ICD trials. Outcome measures included ventricular tachyarrhythmia (VTA), atrial tachyarrhythmia (ATA), ICD therapies, VTA burden (using Andersen-Gill recurrent event analysis), death, and the predicted benefit of the ICD. All events were adjudicated blindly. Outcomes were compared between self-reported Black patients versus White patients with cardiomyopathy (ischemic and NICM).

RESULTS

Black patients were more likely to be female (35% versus 22%) and younger (57±12 versus 62±12 years) with a higher frequency of comorbidities. In NICM, Black patients had a higher rate of first VTA, fast VTA, ATA, and appropriate and inappropriate ICD therapy (VTA ≥170 bpm, 32% versus 20%; VTA ≥200 bpm, 22% versus 14%; ATA, 25% versus 12%; appropriate therapy, 30% versus 20%; and inappropriate therapy, 25% versus 11%; P<0.001 for all). Multivariable analysis showed that Black patients with NICM experienced a higher risk of all types of arrhythmia or ICD therapy (VTA ≥170 bpm, hazard ratio [HR] 1.71; VTA ≥200 bpm, HR 1.58; ATA, HR 1.87; appropriate therapy, HR 1.62; inappropriate therapy, HR 1.86; P≤0.01 for all), higher burden of tachyarrhythmias or therapies (VTA, HR 1.84; appropriate therapy, HR 1.84; P<0.001 for both), and a higher risk of death (HR 1.92; P=0.014). In contrast, in ischemic cardiomyopathy, the risk of all types of tachyarrhythmia, ICD therapy, or death was similar between Black patients and White patients. Both Black patients and White patients derived a significant and similar benefit from ICD implantation.

CONCLUSIONS

Among patients with NICM with an ICD for primary prevention, Black patients compared with White patients had a high risk and burden of VTA, ATA, and ICD therapies with a lower survival rate. Nevertheless, the overall benefit of the ICD was maintained and was similar to that of White patients.

Prognostic impact of morphology and duration of premature ventricular contractions in a population without structural heart disease

BACKGROUND

Premature ventricular contractions (PVCs) are a common form of arrhythmia associated with an unfavorable prognosis in patients with structural heart disease. It is unclear whether PVCs site of origin and QRS-width has a prognostic significance in patients without structural heart disease. The aim of this study was to assess the prognostic importance of PVCs morphology and duration in this patient group.

METHODS

We included 511 consecutive patients without a history of previous heart disease. They were examined with echocardiography and exercise test with normal findings. We categorized the PVCs from a 12 lead ECG according to morphology and width of the QRS-complex and analyzed the outcome in terms of a composite endpoint of total mortality and cardiovascular morbidity.

RESULTS

During a median follow-up time of 5.3 years, 19 patients (3.5%) died and 61 (11.3%) met the composite outcome. Patients with PVCs originating from the outflow tracts had a significantly lower risk for the composite outcome compared to patients with non-OT-PVCs. Similarly, patients with PVC originating from the right ventricle had a better outcome than patients with left ventricular PCVs. No difference in outcome depending on QRS-width during PVCs was noticed.

CONCLUSION

In our cohort of consecutively included PVC patients without structural heart disease PVCs from the outflow tracts were associated with a better prognostic outcome than non-OT PVCs; the same was true for right ventricular PVCs when compared to left ventricular ones. The classification of the origin of the PVCs was based on 12-lead ECG morphology. QRS-width during PVC did not seem to have prognostic significance.

Generation of left ventricle-like cardiomyocytes with improved structural, functional, and metabolic maturity from human pluripotent stem cells

Decreased left ventricle (LV) function caused by genetic mutations or injury often leads to debilitating and fatal cardiovascular disease. LV cardiomyocytes are, therefore, a potentially valuable therapeutical target. Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are neither homogeneous nor functionally mature, which reduces their utility. Here, we exploit cardiac development knowledge to instruct differentiation of hPSCs specifically toward LV cardiomyocytes. Correct mesoderm patterning and retinoic acid pathway blocking are essential to generate near-homogenous LV-specific hPSC-CMs (hPSC-LV-CMs). These cells transit via first heart field progenitors and display typical ventricular action potentials. Importantly, hPSC-LV-CMs exhibit increased metabolism, reduced proliferation, and improved cytoarchitecture and functional maturity compared with age-matched cardiomyocytes generated using the standard WNT-ON/WNT-OFF protocol. Similarly, engineered heart tissues made from hPSC-LV-CMs are better organized, produce higher force, and beat more slowly but can be paced to physiological levels. Together, we show that functionally matured hPSC-LV-CMs can be obtained rapidly without exposure to current maturation regimes.

Role of N-terminal pro-B type natriuretic peptide as a predictor of poor outcomes in patients with HFrEF receiving primary prevention implantable cardioverter-defibrillator therapy: a systematic review and dose-response meta-analysis

INTRODUCTION

Several studies have demonstrated that combining left ventricular ejection fraction and New York Heart Association functional class is insufficient for predicting risk of appropriate implantable cardioverter-defibrillator (ICD) shock in primary prevention candidates. Hence, our aim was to assess the relationship between N-terminal pro-B type natriuretic peptide (NT-pro BNP) along with appropriate ICD shock and all-cause mortality in order to improve the stratification process of patients with heart failure with reduced ejection fraction (HFrEF) being considered for primary preventive ICD therapy.

METHODS

A systematic literature search from several databases was conducted up until 9 June 2022. Studies were eligible if they investigated the relationship of NT-pro BNP with all-cause mortality and appropriate ICD shock.

RESULTS

This meta-analysis comprised nine studies with a total of 5117 participants. Our study revealed that high levels of NT-pro BNP were associated with all-cause mortality (HR=2.12 (95% CI=1.53 to 2.93); p<0.001, I²=78.1%, p<0.001 for heterogeneity) and appropriate ICD shock (HR=1.71 (95% CI=1.18 to 2.49); p<0.001, I²=43.4%, p=0.102 for heterogeneity). The adjusted HR for all-cause mortality and appropriate ICD shock increased by approximately 3% and 5%, respectively per 100 pg/mL increment pursuant to concentration-response model (P_{non-linearity} <0.001). The curves became steeper after NT-pro BNP reached its inflection point (3000 pg/mL).

CONCLUSION

A positive concentration-dependent association between elevated NT-pro BNP levels along with the risk of all-cause mortality and appropriate ICD shock was found in patients with HFrEF with ICD.

PROSPERO REGISTRATION NUMBER

CRD42022339285.

Trends and disparities in ventricular tachycardia mortality in the United States

We aimed to evaluate trends and disparities in mortality from ventricular tachycardia in patients with underlying cardiovascular disease. We performed cross-sectional analyses using publicly available data from the Center for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research database. We identified a total of 7025 deaths from ventricular tachycardia between the years 2007 and 2020. Overall, age-adjusted mortality rates increased from 0.22 in 1999 to 0.32 in 2020 (p < .05). Black female and male adults had higher age-adjusted mortality rates compared to White female and male adults, respectively (p < .05). Disproportionate age-adjusted mortality rates among male populations and Southern residents were also observed. This study demonstrated an increase in deaths related to ventricular tachycardia since 2007. Significant differences in mortality exist across racial, gender, and geographic subgroups.

Electrophysiology, Pathology, and Imaging of Pulsed Field Ablation of Scarred and Healthy Ventricles in Swine

BACKGROUND

Pulsed field ablation (PFA) has recently been shown to penetrate ischemic scar, but details on its efficacy, risk of arrhythmias, and imaging insights are lacking. In a porcine model of myocardial scar, we studied the ability of ventricular PFA to penetrate scarred tissue, induce ventricular arrhythmias, and assess the influence of QRS gating during pulse delivery.

METHODS

Of a total of 6 swine, 5 underwent coronary occlusion and 1 underwent radiofrequency ablation to create infarct scar and iatrogenic scar models, respectively. Two additional swine served as healthy controls. An 8 Fr focal PFA catheter was used to deliver bipolar, biphasic PFA (2.0 kV) lesions guided by electroanatomical mapping, fluoroscopy, and intracardiac echocardiography over both scarred and healthy myocardium. Swine underwent magnetic resonance imaging 2-7 days post-PFA.

RESULTS

PFA successfully penetrated scar without significant difference in lesion depth between lesion at the infarct border (5.9±1.0 mm, n=41) and healthy myocardium (5.7±1.3 mm, n=26; P=0.53). PFA penetration of both infarct and iatrogenic radiofrequency abalation scar was observed in all examined sections. Sustained ventricular arrhythmias requiring defibrillation occurred in 4 of 187 (2.1%) ungated applications, whereas no ventricular arrhythmias occurred during gated PFA applications (0 of 64 [0%]). Dark-blood late-gadolinium-enhanced sequences allowed for improved endocardial border detection as well as lesion boundaries compared with conventional bright-blood late-gadolinium-enhanced sequences.

CONCLUSIONS

PFA penetrates infarct and iatrogenic scar successfully to create deep lesions. Gated delivery eliminates the occurrence of ventricular arrhythmias observed with ungated porcine PFA. Optimized magnetic resonance imaging sequences can be helpful in detecting lesion boundaries.

The Use of Cardiac Stereotactic Radiation Therapy (SBRT) to Manage Ventricular Tachycardia: A Case Report, Review of the Literature and Technical Notes

BACKGROUND

among cardiac arrhythmias, ventricular tachycardia (VT) is one that can lead to cardiac death, although significant progress has been made in its treatment, including the use of implantable cardioverter-defibrillators (ICD) and radiofrequency catheter ablation. Nevertheless, long-term recurrence rates remain in about half of patients and drastically impact the patient's quality of life. Moreover, recurrent ICD shocks are painful and are associated with higher mortality and worsening of heart failure. Recently, more and more experiences are demonstrating potential efficacy in the use of stereotactic body radiotherapy (SBRT) (also called cardiac radio-ablation) to treat this condition. In this paper, we report our experience in the use of cardiac radio-ablation for the treatment of refractory ventricular tachycardia with a focus on the technique used, along with a review of the literature and technical notes.

CASE PRESENTATION

an 81-year-old male patient with a long history of non-ischemic dilated cardiomyopathy and mechanical mitral prosthesis underwent a biventricular cardioverter defibrillator implant after atrial ventricular node ablation. At the end of 2021, the number of tachycardias increased significantly to about 10 episodes per day. After failure of medical treatment and conventional RT catheter ablation, the patient was treated with SBRT for a total dose of 25 Gy in a single session at the site of the ectopic focus. No acute toxicity was recorded. After SBRT (follow-up 7 months) no other VT episodes were recorded.

CONCLUSION

SBRT appears to be safe and leads to a rapid reduction in arrhythmic storms as treatment for VT without acute toxicity, representing one of the most promising methods for treating VT storms.

Evaluation of left cardiac chamber function with cardiac magnetic resonance and association with outcome in patients with systemic sclerosis

OBJECTIVE

This study aimed to determine whether lower values of feature-tracking cardiovascular magnetic resonance (CMR)-derived left atrial reservoir strain (LARS) and impaired left ventricular (LV) global longitudinal strain (GLS) were associated with the presence of symptoms and long-term prognosis in patients with SSc.

METHODS

A total of 100 patients {54 [interquartile range (IQR) 46-64] years, 42% male} with SSc who underwent CMR imaging at two tertiary referral centres were included. All patients underwent analysis of LARS and LV GLS using feature-tracking on CMR and were followed-up for the occurrence of all-cause mortality.

RESULTS

The median LV GLS was -21.8% and the median LARS was 36%. On multivariable logistic regression, LARS [odds ratio (OR) 0.964 per %, 95% CI 0.929, 0.998, P = 0.049] was independently associated with New York Heart Association (NYHA) class II-IV heart failure symptoms. Over a median follow-up of 37 (21-62) months, a total of 24 (24%) patients died. Univariable Cox regression analysis demonstrated that LARS [hazard ratio (HR) 0.94 per 1%, 95% CI 0.91, 0.97, P < 0.0001) and LV GLS (HR 1.10 per %, 95% CI 1.03, 1.17, P = 0.005) were associated with all-cause mortality, while LV ejection fraction was not. Likelihood ratio tests demonstrated that LARS provided incremental value over prognostically important clinical and imaging parameters, including late gadolinium enhancement.

CONCLUSION

In patients with SSc, LARS was independently associated with the presence of NYHA class II-IV heart failure symptoms. Although both LARS and LV GLS were associated with all-cause mortality, only LARS provided incremental value over all evaluated variables known to be prognostically important in patients with SSc.

The Subventricular Zone in Glioblastoma: Genesis, Maintenance, and Modeling

Glioblastoma (GBM) is a malignant tumor with a median survival rate of 15-16 months with standard care; however, cases of successful treatment offer hope that an enhanced understanding of the pathology will improve the prognosis. The cell of origin in GBM remains controversial. Recent evidence has implicated stem cells as cells of origin in many cancers. Neural stem/precursor cells (NSCs) are being evaluated as potential initiators of GBM tumorigenesis. The NSCs in the subventricular zone (SVZ) have demonstrated similar molecular profiles and share several distinctive characteristics to proliferative glioblastoma stem cells (GSCs) in GBM. Genomic and proteomic studies comparing the SVZ and GBM support the hypothesis that the tumor cells and SVZ cells are related. Animal models corroborate this connection, demonstrating migratory patterns from the SVZ to the tumor. Along with laboratory and animal research, clinical studies have demonstrated improved progression-free survival in patients with GBM after radiation to the ipsilateral SVZ. Additionally, key genetic mutations in GBM for the most part carry regulatory roles in the SVZ as well. An exciting avenue towards SVZ modeling and determining its role in gliomagenesis in the human context is human brain organoids. Here we comprehensively discuss and review the role of the SVZ in GBM genesis, maintenance, and modeling.

Impact of cascade screening for catecholaminergic polymorphic ventricular tachycardia type 1

Objective

Human cardiac ryanodine receptor 2 (RYR2) shows autosomal-dominant inheritance in catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1); however, de novo variants have been observed in sporadic cases. Here, we investigated CPVT1-related RYR2 variant inheritance and its clinical significance between familial and de novo cases.

Methods

We enrolled 82 independent CPVT1 probands (median age: 10.0 (7.0–13.0) years; 45 male) carrying the RYR2 variants and whose biological origin could be confirmed by parental genetic analysis: assured familial inheritance (familial group: n=24) and de novo variants (de novo group: n=58). We examined the clinical characteristics of the probands and their family members carrying the RYR2 variants.

Results

In the de novo group, the RYR2 variants were more likely located in the C-terminus domain and less likely in the N-terminus domain than those in the familial group. The cumulative incidence of the first cardiac events (syncope and cardiac arrest (CA) or CA only) of the probands at the age of 5 and 10 years was higher in the de novo group than in the familial group. Nearly half of the probands in both groups experienced CA events before diagnosis. Only 37.5% of their genotype-positive parents had symptoms; however, at least 66.7% of the genotype-positive siblings were symptomatic.

Conclusions

CPVT1 probands harbouring de novo RYR2 variants showed an earlier onset of symptoms than those with assured familial inheritance. Cascade screening may enable early diagnosis, risk stratification and prophylactic therapeutic intervention to prevent sudden cardiac death of probands and potential genotype-positive family members.

Pathogenic Mechanisms Underlying Cirrhotic Cardiomyopathy

Cardiac dysfunction associated with cirrhosis in the absence of preexisting heart disease is a condition known as cirrhotic cardiomyopathy (CCM). Cardiac abnormalities consist of enlargement of cardiac chambers, attenuated systolic and diastolic contractile responses to stress stimuli, and repolarization changes. CCM may contribute to cardiovascular morbidity and mortality after liver transplantation and other major surgeries, and also to the pathogenesis of hepatorenal syndrome. The underlying mechanisms of CCM are poorly understood and as such medical therapy is an area of unmet medical need. The present review focuses on the pathogenic mechanisms responsible for development of CCM. The two major concurrent mechanistic pathways are the inflammatory phenotype due to portal hypertension, and protein/lipid synthetic/metabolic defects due to cirrhosis and liver insufficiency. The inflammatory phenotype arises from intestinal congestion due to portal hypertension, resulting in bacteria/endotoxin translocation into the systemic circulation. The cytokine storm associated with inflammation, particularly TNFα acting via NFκB depresses cardiac function. They also stimulate two evanescent gases, nitric oxide and carbon monoxide which produce cardiodepression by cGMP. Inflammation also stimulates the endocannabinoid CB-1 pathway. These systems inhibit the stimulatory beta-adrenergic contractile pathway. The liver insufficiency of cirrhosis is associated with defective synthesis or metabolism of several substances including proteins and lipids/lipoproteins. The protein defects including titin and collagen contribute to diastolic dysfunction. Other protein abnormalities such as a switch of myosin heavy chain isoforms result in systolic dysfunction. Lipid biochemical changes at the cardiac sarcolemmal plasma membrane result in increased cholesterol:phospholipid ratio and decreased membrane fluidity. Final common pathway changes involve abnormal cardiomyocyte intracellular ion kinetics, particularly calcium. In conclusion, cirrhotic cardiomyopathy is caused by two pathways of cellular and molecular dysfunction/damage due to hepatic insufficiency and portal hypertension.

Synthesis and Biological Activity of the Pyridine-Hexacyclic-Steroid Derivative on a Heart Failure Model

BACKGROUND

Several drugs with inotropic activity have been synthesized; however, there is very little information on biological activity exerted by steroid derivatives in the cardiovascular system.

OBJECTIVE

The aim of this research was to prepare a steroid-pyridine derivative to evaluate the effect it exerts on left ventricular pressure and characterize its molecular interaction.

METHODS

The first stage was carried out through the synthesis of a steroid-pyridine derivative using some chemical strategies. The second stage involved the evaluation of the biological activity of the steroid-pyridine derivative on left ventricular pressure using a model of heart failure in the absence or presence of the drugs, such as flutamide, tamoxifen, prazosin, metoprolol, indomethacin, and nifedipine.

RESULTS

The results showed that steroid-pyridine derivative increased left ventricular pressure in a dose-dependent manner (0.001-100 nM); however, this phenomenon was significantly inhibited only by nifedipine at a dose of 1 nM. These results indicate that positive inotropic activity produced by the steroid-pyridine derivative was via calcium channel activation. Furthermore, the biological activity exerted by the steroid-pyridine derivative on the left ventricle produces changes in cAMP concentration.

CONCLUSION

It is noteworthy that positive inotropic activity produced by this steroid-pyridine derivative involves a different molecular mechanism compared to other positive inotropic drugs. Therefore, this steroid could be a good candidate for the treatment of heart failure.

Complications in Patients with Cardiac Penetrating Trauma

BACKGROUND

Cardiac penetrating trauma is a medical emergency that mostly affects young people. Based on the type of injury and associated complications, it can present as a surgical challenge and can lead to mortality.

OBJECTIVE

The aim of this study is to evaluate the complications of penetrating heart trauma among patients referred to Shahid Madani Hospital.

METHODS

In this retrospective descriptive study, the data of penetrating cardiac trauma patients referred to Shahid Madani hospital, Karaj, Tehran, from 2016-2019, were investigated. Information, including age, sex, cause of trauma, traumatized area and complications, was extracted and recorded in a data collection form. The data were evaluated statistically using SPSS v18.

RESULTS

A total of 44 patients were included in the study, where the mean age of the patients was 25 years. 73.3% of these patients were men and 26.7% were women. Knife stab wounds were the most prevalent cause of the trauma, present in 93.3% of patients. 73.3% of the patients had cardiac tamponade and 20% had a pneumothorax. The right ventricle was the most common site of the injury in 46.7% of the patients. A mortality rate of 3.4% was reported in this study.

CONCLUSION

The results of this study showed that the highest penetrating heart rate trauma occurred among young people, and the most common cause of the trauma was a knife stab. The most common area of the injury was the right ventricular, and cardiac tamponade was the most common complication.

Cardiac stereotactic ablative radiotherapy for control of refractory ventricular tachycardia: initial UK multicentre experience

Background

Options for patients with ventricular tachycardia (VT) refractory to antiarrhythmic drugs and/or catheter ablation remain limited. Stereotactic radiotherapy has been described as a novel treatment option.

Methods

Seven patients with recurrent refractory VT, deemed high risk for either first time or redo invasive catheter ablation, were treated across three UK centres with non-invasive cardiac stereotactic ablative radiotherapy (SABR). Prior catheter ablation data and non-invasive mapping were combined with cross-sectional imaging to generate radiotherapy plans with aim to deliver a single 25 Gy treatment. Shared planning and treatment guidelines and prospective peer review were used.

Results

Acute suppression of VT was seen in all seven patients. For five patients with at least 6 months follow-up, overall reduction in VT burden was 85%. No high-grade radiotherapy treatment-related side effects were documented. Three deaths (two early, one late) occurred due to heart failure.

Conclusions

Cardiac SABR showed reasonable VT suppression in a high-risk population where conventional treatment had failed.

Mortality and ventricular arrhythmia after acute myocarditis: a nationwide registry-based follow-up study

Objective

Incidence and severity of acute myocarditis vary significantly in previous reports and there is a lack of epidemiological studies on the short-term risks of mortality, heart failure and ventricular arrhythmias in patients with acute myocarditis. Therefore, study aims were to examine 90-day risks of mortality, heart failure (HF) and ventricular arrhythmias in patients with acute myocarditis in comparison to age-matched and sex-matched background population controls.

Methods

In this nationwide register-based follow-up study of patients hospitalised with myocarditis between 2002 and 2018 in Denmark, 90-day risks of all-cause mortality, HF, ventricular arrhythmias (ventricular tachycardia, ventricular fibrillation (VF)), cardiac arrest and implantable cardioverter-defibrillator (ICD) implantation were compared with age-matched and sex-matched controls from the background population (1:5 matching). Absolute risks standardised to the age, sex and comorbidity distribution of the entire study population were derived from multivariable Cox regression.

Results

A total of 2523 patients hospitalised with myocarditis were included. Median age was 48 years (Q1–Q3: 30–69) and 67.7% were men. Comorbidity burden was more pronounced among patients with myocarditis relative to controls. Standardised 90-day all-cause mortality risk was 4.9% for patients with acute myocarditis versus 0.3% for controls (p<0.001). Ninety-day standardised risks for other endpoints were 7.5% versus 0.1% for HF, 1.9% versus <0.1% for VF/VF/arrest risk and 1.6% versus <0.1% for ICD implantation (all p<0.001).

Conclusions

In this large nationwide register-based follow-up study, patients hospitalised with myocarditis had significantly higher 90-day risks of all-cause mortality, HF, ventricular arrhythmias, cardiac arrest and ICD implantation compared with background population controls.

Association of bleeding with serotonergic antidepressants in patients receiving left ventricular assist device support

STUDY OBJECTIVE

This study sought to determine whether SA use is associated with bleeding in patients receiving CF-LVAD support.

DESIGN

A retrospective cohort analysis was conducted of all adult patients who received CF-LVAD implantation at our institution.

SETTING

Barnes-Jewish Hospital between July 1, 2009, and October 1, 2018.

PATIENTS

Patients at least 18 years of age who received a HVAD™ (HeartWare Corp.), HeartMate II™ (St. Jude Medical), or HeartMate 3™ (St. Jude Medical) CF-LVAD and survived for at least 30 days postoperatively were included.

INTERVENTION

Patients who received SAs (n = 203) were compared to those who did not (n = 391) from 30 days to 18 months following implantation. The primary outcome was the incidence of first bleeding events including gastrointestinal bleed (GIB), epistaxis, or intracerebral hemorrhage (ICH).

MEASUREMENTS AND MAIN RESULTS

During follow-up, 219 patients had bleeding events: 93 of 203 (45.8%) in the SA group versus 126 of 391 (32.2%) in the control group (p = 0.001). After adjustment for age, angiotensin-converting enzyme (ACE) inhibitor and angiotensin receptor blocker (ARB) use, history of bleeding events, history of smoking, and CF-LVAD type, SA use remained associated with bleeding (adjusted odds ratio: 1.75, 95% confidence interval: 1.22-2.51, p = 0.002). HeartMate 3™ patients experienced less bleeding than HeartMate II™ patients (adjusted odds ratio 0.46, 95% confidence interval: 0.23-0.90, p = 0.024).

CONCLUSIONS

In this single-center, retrospective cohort of patients supported with CF-LVADs, SA use was associated with the incidence of first bleeding events, primarily driven by GIB. Further studies are needed to assess any differential risk of bleeding among SA agents and to assess the utility of altering antithrombotic strategies.

Paediatric/young versus adult patients with long QT syndrome

Introduction

Long QT syndrome (LQTS) is a less prevalent cardiac ion channelopathy than Brugada syndrome in Asia. The present study compared the outcomes between paediatric/young and adult LQTS patients.

Methods

This was a population-based retrospective cohort study of consecutive patients diagnosed with LQTS attending public hospitals in Hong Kong. The primary outcome was spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF).

Results

A total of 142 LQTS (mean onset age=27±23 years old) were included. Arrhythmias other than VT/VF (HR 4.67, 95% CI (1.53 to 14.3), p=0.007), initial VT/VF (HR=3.25 (95% CI 1.29 to 8.16), p=0.012) and Schwartz score (HR=1.90 (95% CI 1.11 to 3.26), p=0.020) were predictive of the primary outcome for the overall cohort, while arrhythmias other than VT/VF (HR=5.41 (95% CI 1.36 to 21.4), p=0.016) and Schwartz score (HR=4.67 (95% CI 1.48 to 14.7), p=0.009) were predictive for the adult subgroup (>25 years old; n=58). A random survival forest model identified initial VT/VF, Schwartz score, initial QTc interval, family history of LQTS, initially asymptomatic and arrhythmias other than VT/VF as the most important variables for risk prediction.

Conclusion

Clinical and ECG presentation varies between the paediatric/young and adult LQTS population. Machine learning models achieved more accurate VT/VF prediction.

Surgical ablation supplemented by ethanol injection for ventricular tachycardia refractory to percutaneous ablation

BACKGROUND

A combination of endocardial and epicardial approaches has improved the overall success rate of ventricular tachycardia (VT) ablation in patients with cardiomyopathy. However, the origins of some VTs are truly intramural or close to coronary arteries, which makes this combined strategy either prone to failure or too risky.

OBJECTIVES

This observational study aimed to explore the feasibility and efficacy of direct epicardial ablation combined with intramural ethanol injection via surgical approach for inaccessible intramural VTs or VTs too close to coronary arteries.

METHODS

In four canines ventricular lesions produced by direct epicardial injection of ethanol were assessed. Six consecutive patients with recurrent VT refractory to catheter endocardial and epicardial RF ablation and that remained inducible after surgical epicardial mapping and RF ablation were included. Ethanol was injected by needle at the epicardial RF ablation sites. The primary outcome was freedom of sustained VT determined by device interrogation and periodical 24-h holter recordings subsequently.

RESULTS

In an animal study, the lesions were homogenous and increased in size with the volume of ethanol injected. In all six patients, ethanol injection at the target sites in the anterior or lateral left ventricle abolished inducible VT. Over a median follow-up of 22 months (range, 6-65), all patients remained free of sustained VT. One patient died of pulmonary infection one year after the procedure.

CONCLUSIONS

A hybrid strategy of surgical ablation combined with intramural ethanol injection is feasible and effective in patients with multiple failed percutaneous ablation attempts.

Mechanical Complications of Acute Myocardial Infarction: A Scientific Statement From the American Heart Association

Over the past few decades, advances in pharmacological, catheter-based, and surgical reperfusion have improved outcomes for patients with acute myocardial infarctions. However, patients with large infarcts or those who do not receive timely revascularization remain at risk for mechanical complications of acute myocardial infarction. The most commonly encountered mechanical complications are acute mitral regurgitation secondary to papillary muscle rupture, ventricular septal defect, pseudoaneurysm, and free wall rupture; each complication is associated with a significant risk of morbidity, mortality, and hospital resource utilization. The care for patients with mechanical complications is complex and requires a multidisciplinary collaboration for prompt recognition, diagnosis, hemodynamic stabilization, and decision support to assist patients and families in the selection of definitive therapies or palliation. However, because of the relatively small number of high-quality studies that exist to guide clinical practice, there is significant variability in care that mainly depends on local expertise and available resources.

Diagnosis, management and therapeutic strategies for congenital long QT syndrome

Congenital long QT syndrome (LQTS) is characterised by heart rate corrected QT interval prolongation and life-threatening arrhythmias, leading to syncope and sudden death. Variations in genes encoding for cardiac ion channels, accessory ion channel subunits or proteins modulating the function of the ion channel have been identified as disease-causing mutations in up to 75% of all LQTS cases. Based on the underlying genetic defect, LQTS has been subdivided into different subtypes. Growing insights into the genetic background and pathophysiology of LQTS has led to the identification of genotype–phenotype relationships for the most common genetic subtypes, the recognition of genetic and non-genetic modifiers of phenotype, optimisation of risk stratification algorithms and the discovery of gene-specific therapies in LQTS. Nevertheless, despite these great advancements in the LQTS field, large gaps in knowledge still exist. For example, up to 25% of LQTS cases still remain genotype elusive, which hampers proper identification of family members at risk, and it is still largely unknown what determines the large variability in disease severity, where even within one family an identical mutation causes malignant arrhythmias in some carriers, while in other carriers, the disease is clinically silent. In this review, we summarise the current evidence available on the diagnosis, clinical management and therapeutic strategies in LQTS. We also discuss new scientific developments and areas of research, which are expected to increase our understanding of the complex genetic architecture in genotype-negative patients, lead to improved risk stratification in asymptomatic mutation carriers and more targeted (gene-specific and even mutation-specific) therapies.

Cardiac intramural arteriovenous malformations presented as ventricular tachycardia and fibrillation storm

We report a case of cardiac intramural arteriovenous malformations (AVMs) misdiagnosed as hypertrophic cardiomyopathy and presented as life-threatening ventricular arrhythmia storm that was successfully controlled by cardiac sympathetic denervation. A 46-year-old male patient with an implantable cardioverter-defibrillator was admitted for recurrent ventricular tachycardia requiring repeated shock refractory to antiarrhythmic drugs. Although the patient was previously diagnosed with hypertrophic cardiomyopathy, multimodality imaging studies showed large left ventricular intramural AVMs, potentially representing arrhythmogenic substrates. Life-threatening ventricular arrhythmia storm, which could not be controlled by radiofrequency catheter ablation and therapeutic hypothermia. However, cardiac sympathetic denervation surgery successfully controlled the ventricular arrhythmia storm.

Translational applications of computational modelling for patients with cardiac arrhythmias

Cardiac arrhythmia is associated with high morbidity, and its underlying mechanisms are poorly understood. Computational modelling and simulation approaches have the potential to improve standard-of-care therapy for these disorders, offering deeper understanding of complex disease processes and sophisticated translational tools for planning clinical procedures. This review provides a clinician-friendly summary of recent advancements in computational cardiology. Organ-scale models automatically generated from clinical-grade imaging data are used to custom tailor our understanding of arrhythmia drivers, estimate future arrhythmogenic risk and personalise treatment plans. Recent mechanistic insights derived from atrial and ventricular arrhythmia simulations are highlighted, and the potential avenues to patient care (eg, by revealing new antiarrhythmic drug targets) are covered. Computational approaches geared towards improving outcomes in resynchronisation therapy have used simulations to elucidate optimal patient selection and lead location. Technology to personalise catheter ablation procedures are also covered, specifically preliminary outcomes form early-stage or pilot clinical studies. To conclude, future developments in computational cardiology are discussed, including improving the representation of patient-specific fibre orientations and fibrotic remodelling characterisation and how these might improve understanding of arrhythmia mechanisms and provide transformative tools for patient-specific therapy.

Swiss-cheese ventricular septal defect closure by combination sandwich patch

A 7-year-old boy with a history of neonatal pulmonary artery banding underwent almost complete closure of a sieve-like "Swiss-cheese" ventricular septal defect, using a combination sandwich patch technique through a right ventriculotomy. Although defects existed in the high-, mid-, and low-trabecular septa, a right ventriculotomy and division of the muscle trabeculations continuing the septal and moderator bands helped delineate the edges of the defects. Although patients with "Swiss-cheese" ventricular septal defects may be candidates for a Fontan operation conventionally, a combination patch technique could be considered the procedure of choice.

Video-thoracoscopic left cardiac sympathetic denervation for long-QT syndrome

BACKGROUND

Congenital long-QT syndrome represents the most common cardiac channelopathy and manifests as potentially lethal ventricular arrhythmias. Prevention strategies include beta-blockade pharmacotherapy, implantable cardioverter-defibrillators, and left cardiac sympathetic denervation, which can increase the threshold for ventricular fibrillation. Herein, we report our experience with video-assisted thoracoscopic left cardiac sympathetic denervation.

METHODS

We performed a retrospective review of the electronic medical records of all patients with congenital long-QT syndrome who underwent video-assisted thoracoscopic left cardiac sympathetic denervation at our institution.

RESULTS

From September 2009 to May 2016, 6 patients with a mean age of 30.5 years (range 20-47 years) underwent video-assisted thoracoscopic left cardiac sympathetic denervation for medically refractory long-QT syndrome. All patients had an uneventful recovery and were discharged 1-3 days after the operation. At a median follow-up of 14 months (range 12-60 months), 4 patients had no cardiac events while 2 experienced 1 episode of arrhythmic syncope and 1 episode of appropriate implantable cardioverter-defibrillator shock. Following surgery, the mean annual cardiac events in the study cohort decreased from 2.13 to 0.33 (p = 0.004) and the mean corrected QT interval reduced from 560 ms to 491 ms (p = 0.006).

CONCLUSIONS

Video-assisted thoracoscopic left cardiac sympathetic denervation is a safe and effective therapy in patients with congenital long-QT syndrome who continue to suffer from recurrent life-threatening arrhythmias or frequent implantable cardioverter-defibrillator discharges despite maximum tolerated doses of beta blockers.

Single coronary artery arising from an atretic pulmonary trunk

Coronary artery anomalies are a diverse group of disorders with highly variable manifestations and pathophysiological mechanisms. The origin of a single coronary artery from an atretic pulmonary trunk is a rare anomaly. We encountered this in an 8-day-old female newborn. This report should alert the cardiac surgical community to this fatal coronary malformation. Surgeons should bear this anomaly in mind when they face unusual myocardial behavior intraoperatively.

Multipronged approach to a patient with ventricular tachycardia storm

Management of ventricular tachycardia storm requires multimodal aggressive therapeutic interventions for a successful outcome. A 39-year-old man with dilated cardiomyopathy and severe left ventricular dysfunction presented with refractory ventricular tachycardia unresponsive to conventional treatment. He underwent an electrophysiology study and radiofrequency ablation with 3-dimensional mapping with partial control of the ventricular tachycardia. Further left sympathetic ganglion block followed by left cardiac sympathetic denervation also did not totally control the ventricular tachycardia. Right cardiac sympathetic denervation resulting in bilateral cardiac sympathetic denervation controlled the ventricular tachycardia.

Corridor technique for coronary arteries from a single arterial sinus

The introduction of the arterial switch operation has improved the surgical outcome of transposition of the great arteries. However, coronary anomalies such as intramural coronary arteries, single coronary artery, or coronary arteries originating from a single arterial sinus have been reported as independent risk factors for early mortality and late morbidity after an arterial switch operation. We performed an arterial switch operation using a unique technique for translocation of the coronary arteries originating from a single left-side arterial sinus, to prevent coronary artery distortion and subsequent coronary malperfusion.

Prenatal and Postnatal Cardiac Development in Offspring of Hypertensive Pregnancies

Background

Pregnancy complications such as preterm birth and fetal growth restriction are associated with altered prenatal and postnatal cardiac development. We studied whether there were changes related specifically to pregnancy hypertension.

Methods and Results

Left and right ventricular volumes, mass, and function were assessed at birth and 3 months of age by echocardiography in 134 term‐born infants. Fifty‐four had been born to mothers who had normotensive pregnancy and 80 had a diagnosis of preeclampsia or pregnancy‐induced hypertension. Differences between groups were interpreted, taking into account severity of pregnancy disorder, sex, body size, and blood pressure. Left and right ventricular mass indexed to body surface area (LVMI and RVMI) were similar in both groups at birth (LVMI 20.9±3.7 versus 20.6±4.0 g/m², P=0.64, RVMI 17.5±3.7 versus 18.1±4.7 g/m², P=0.57). However, right ventricular end diastolic volume index was significantly smaller in those born to hypertensive pregnancy (16.8±5.3 versus 12.7±4.7 mL/m², P=0.001), persisting at 3 months of age (16.4±3.2 versus 14.4±4.8 mL/m², P=0.04). By 3 months of age these infants also had significantly greater LVMI and RVMI (LVMI 24.9±4.6 versus 26.8±4.9 g/m², P=0.04; RVMI 17.1±4.2 versus 21.1±3.9 g/m², P<0.001). Differences in RVMI and right ventricular end diastolic volume index at 3 months, but not left ventricular measures, correlated with severity of the hypertensive disorder. No differences in systolic or diastolic function were evident.

Conclusions

Infants born at term to a hypertensive pregnancy have evidence of both prenatal and postnatal differences in cardiac development, with right ventricular changes proportional to the severity of the pregnancy disorder. Whether differences persist long term as well as their underlying cause and relationship to increased cardiovascular risk requires further study.

May the Force Not Be With You During Culture: Eliminating Mechano-Associated Feedback During Culture Preserves Cultured Atrial and Pacemaker Cell Functions

Cultured cardiomyocytes have been shown to possess significant potential as a model for characterization of mechano-Ca²⁺, mechano-electric, and mechano-metabolic feedbacks in the heart. However, the majority of cultured cardiomyocytes exhibit impaired electrical, mechanical, biochemical, and metabolic functions. More specifically, the cells do not beat spontaneously (pacemaker cells) or beat at a rate far lower than their physiological counterparts and self-oscillate (atrial and ventricular cells) in culture. Thus, efforts are being invested in ensuring that cultured cardiomyocytes maintain the shape and function of freshly isolated cells. Elimination of contraction during culture has been shown to preserve the mechano-Ca²⁺, mechano-electric, and mechano-metabolic feedback loops of cultured cells. This review focuses on pacemaker cells, which reside in the sinoatrial node (SAN) and generate regular heartbeat through the initiation of the heart’s electrical, metabolic, and biochemical activities. In parallel, it places emphasis on atrial cells, which are responsible for bridging the electrical conductance from the SAN to the ventricle. The review provides a summary of the main mechanisms responsible for mechano-electrical, Ca²⁺, and metabolic feedback in pacemaker and atrial cells and of culture methods existing for both cell types. The work concludes with an explanation of how the elimination of mechano-electrical, mechano-Ca²⁺, and mechano-metabolic feedbacks during culture results in sustained cultured cell function.

Engineered Maturation Approaches of Human Pluripotent Stem Cell-Derived Ventricular Cardiomyocytes

Heart diseases such as myocardial infarction and myocardial ischemia are paroxysmal and fatal in clinical practice. Cardiomyocytes (CMs) differentiated from human pluripotent stem cells provide a promising approach to myocardium regeneration therapy. Identifying the maturity level of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) is currently the main challenge for pathophysiology and therapeutics. In this review, we describe current maturity indicators for cardiac microtissue and microdevice cultivation technologies that accelerate cardiac maturation. It may provide insights into regenerative medicine, drug cardiotoxicity testing, and preclinical safety testing.

Examination of the Effects of Conduction Slowing on the Upstroke of Optically Recorded Action Potentials

Introduction

The upstroke of optical action potentials (APs) recorded from intact hearts are generally recognized to be slower than those recorded with microelectrodes. This is thought to reflect spatial signal averaging within the volume of tissue that makes up the optical signal. However, to date, there has been no direct experimental study on the relationship between conduction velocity (CV) and optical AP upstroke morphology in the intact heart. Notably, it is known that sodium channel block and gap junction inhibition, which both slow CV, exert differential effects on the upstroke velocity of microelectrode-recorded APs. Whether such differences are evident in optical APs is not known. The present study sought to determine the relationship between tissue CV and optical AP upstroke velocity in intact mouse hearts.

Materials and Methods

Isolated, perfused mouse hearts were stained with the potentiometric dye Rh-237. Fluorescent signals were recorded from across the anterior surface of the left and right ventricles during constant pacing. Maximum rate of change in fluorescence (dF/dt_max) and tissue CV were assessed in control conditions, during an acute period of low-flow ischemia, and following perfusion of flecainide (1–3 μmol/L), a sodium channel blocker, or carbenoxolone (10–50 μmol/L), a gap junction inhibitor.

Results

During epicardial pacing, an anisotropic pattern was observed in both activation and dF/dt_max maps, with more rapid optical AP upstroke velocities orientated along the fastest conduction paths (and vice versa). Low-flow ischemia resulted in a time-dependent slowing of ventricular CV, which was accompanied by a concomitant reduction in optical AP upstroke velocity. All values returned to baseline on tissue reperfusion. Both flecainide and carbenoxolone were associated with a concentration-dependent reduction in CV and decrease in optical AP upstroke velocity, despite distinct mechanisms of action. Similar responses to carbenoxolone were observed for low- (156 μm pixel with) and high- (20 μm pixel width) magnification recordings. Comparison of data from all interventions revealed a linear relationship between CV and upstroke dF/dt.

Conclusion

In intact mouse hearts, slowing of optical AP upstroke velocity is directly proportional to the change in CV associated with low-flow ischemia, sodium channel block, and gap junction inhibition.

Patch and glue repair for extensive left ventricular laceration

Laceration of the left ventricular wall is a rare but potentially life-threatening complication of electrophysiological studies. We describe emergency surgery on a 64-year-old man who suffered cardiac tamponade after an electrophysiological study, which revealed an extensive laceration in the inferior left ventricular wall, requiring repair by a patch and glue technique, with a good clinical outcome.

Clinical course in children and adolescents with ventricular septal defect

Background

Ventricular septal defect, the most common congenital heart defect, is characterized by an opening between the ventricles. This study aimed to evaluate the clinical course and associations between the characteristics of ventricular septal defect.

Methods

This cross-sectional study was conducted on 1498 children with ventricular septal defects, aged <19 years, who were referred to our center between 2003 and 2018. The diagnosis was suspected from a combination of clinical and laboratory findings, and confirmed by transthoracic echocardiography.

Results

Of the 1498 children, 54.9% were boys, 78.4% of defects were perimembranous, 30.4% of patients had pulmonary hypertension, 67.5% had regular follow-up, and 76 (5.1%) had complications including 28 (1.9%) with Eisenmenger syndrome; 10 died due to Eisenmenger syndrome during follow-up. The defects closed spontaneously in 38.9% and after surgery in 20.9%. Boys tended to have more perimembranous, inlet, and outlet forms (56.40%, 50.60%, 51.90%, respectively), whereas girls had more muscular types (51.80%). Most patients with pulmonary hypertension had perimembranous defects (83.10%). The majority of patients with pulmonary hypertension had large (63.40%) or moderate (36.60%) defects. Pulmonary hypertension had a significant association with defect size ( p < 0.001). After surgery, residual defects were found mostly in cases of large defects (84.60%). Most patients with spontaneous closure were younger than 4 years.

Conclusion

Almost four-fifths of children with ventricular septal defects had perimembranous types, and almost one-third had pulmonary hypertension which was associated with defect size. Two-fifths of the defects closed spontaneously. There was a low incidence of complications after surgery.

Adams-Stokes attack with delayed heart block after ventricular septal repair

A child with Down syndrome, who had undergone uneventful ventricular septal defect repair one year earlier with a normal heart rate during routine follow-up, presented with recurrent seizure-like episodes that did not respond to antiepileptics. She was subsequently found to have complete heart block with significant bradycardia requiring permanent pacemaker insertion. This late and unusual presentation of complete heart block after ventricular septal defect repair is discussed. Prudence must be applied in the evaluation of children who have undergone surgical correction of congenital heart defects and presented with recurrent seizure-like episodes.