Neonatal Arrhythmias Research Articles

Achado incidental de taquicardia supraventricular com evolução para Flutter atrial após cardioversão elétrica em neonato

Cardiac arrhythmias in newborns, although rare, are often associated with prematurity and congenital heart defects. Atrial flutter, a tachyarrhythmia with a continuous, elevated atrial rhythm, occurs in about 1% of pediatric cases and usually in previously healthy hearts. Supraventricular tachycardia (SVT), an abnormality in electrical conduction above the ventricles, can cause symptoms such as difficulty feeding and irritability. In neonates, SVT may be asymptomatic for long periods but may lead to sudden hemodynamic decompensation. Treatment includes antiarrhythmic medications, with adenosine being the first line. In refractory cases, such as the one described, amiodarone and synchronized electrical cardioversion may be necessary. The case reported describes a newborn with SVT and persistent Atrial Flutter, treated with adenosine, amiodarone and synchronized electrical cardioversion, resulting in normalization of the heart rhythm. The patient progressed well with oral amiodarone, with no sequelae. The combination of drugs and electrical cardioversion is effective for treating complex neonatal arrhythmias.

Clinical Outcomes and Medical Burdens of Neonatal Arrhythmias in Children's Hospitals in China: A Protocol for Multi-Center Retrospective Cohort Study.

Neonatal arrhythmias are significant contributors to infant mortality. Timely diagnosis and treatment are essential for neonates with non-benign arrhythmias to avoid severe complications, and ongoing treatment and follow-up are sometimes needed. The main objective of this study will be to understand the incidence and demographic characteristics of arrhythmias in hospitalized neonates in China and the related factors of outcomes. A secondary objective will be to establish the first follow-up system for neonatal arrhythmias in China. The medical burdens of neonatal arrhythmias in China will also be investigated. The data from the Futang Research Center of Pediatric Development (FRCPD) database between January 2016 and December 2021 were obtained. Newborns admitted to member hospitals with a discharge diagnosis of "neonatal arrhythmia" (ICD-10 code P29.151) or "arrhythmia" (ICD-10 code I49.904) were included. The medical record information was collected and classified into two groups: heart failure and non-heart failure. The differences between the two groups and independent risk factors for neonatal arrhythmias complicated with heart failure were analyzed. In addition, a follow-up study of patients discharged from Beijing Children's Hospital was conducted to evaluate their outcomes at the age of 3 years old. Factors influencing hospitalization costs were analyzed using rank-sum tests and multiple linear regression. It is anticipated that the study findings will provide new and comprehensive data on the health needs of neonatal arrhythmias in China. The study will establish the first follow-up system for neonatal arrhythmias in China. This study will help reduce the burden of patients and their families as well as the society.

Rediscover the predictive capacity of B-type natriuretic peptide applied to neonatal supraventricular tachycardia

BackgroundSupraventricular tachycardia (SVT) is one of the most common non-benign arrhythmias in neonates, potentially leading to cardiac decompensation. This study investigated the early risk factors of acute heart failure (AHF) secondary to SVT in neonates, and explored their value in guiding the selection of effective anti-arrhythmic treatment.MethodsA total of 43 newborns diagnosed with and treated for SVT between January 2017 and December 2022 were analyzed. According to the presence of AHF after restoring sinus rhythm in newborns with SVT, they were divided into SVT with AHF group and SVT without AHF group. Clinical data and anti-arrhythmic therapies were analyzed. Risk factors of AHF secondary to SVT in neonates were determined using logistic regression. The cut-off value for predictors of AHF secondary to SVT and demanding of a second-line anti-arrhythmic treatment was determined through receiver operating characteristic (ROC) analysis.ResultsTime to initial control of tachycardia > 24 h, hyperkalemia, anemia, and plasma B-type natriuretic peptide (BNP) were identified as risk factors of AHF secondary to SVT in neonates. BNP exhibited AUC of 0.80 in predicting AHF, and BNP > 2460.5pg/ml (OR 2.28, 95% CI 1.27 ~ 45.39, P = 0.03) was an independent predictor, yielding sensitivity of 70.6% and specificity of 84.6%. Neonates with BNP > 2460.5pg/ml (37.5% versus 7.4%, P = 0.04) had a higher demand for a second line anti-arrhythmic treatment to terminate SVT, with sensitivity and specificity for BNP in predicting at 75.0%, 71.4%, respectively.ConclusionsBNP could be used to predict an incident of AHF secondary to SVT and a demand of second-line anti-arrhythmic treatment to promptly terminate SVT and prevent decompensation in neonates.

A Case Series of Neonatal Arrhythmias at Multiple Centres in North Maharashtra, India

A Case Series of Neonatal Arrhythmias at Multiple Centres in North Maharashtra, India

Remodeling of lipid landscape in high fat fed very-long chain acyl-CoA dehydrogenase null mice favors pro-arrhythmic polyunsaturated fatty acids and their downstream metabolites

Very-long chain acyl-CoA dehydrogenase (VLCAD) catalyzes the initial step of mitochondrial long chain (LC) fatty acid β-oxidation (FAO). Inherited VLCAD deficiency (VLCADD) predisposes to neonatal arrhythmias whose pathophysiology is still not understood. We hypothesized that VLCADD results in global disruption of cardiac complex lipid homeostasis, which may set conditions predisposing to arrhythmia. To test this, we assessed the cardiac lipidome and related molecular markers in seven-month-old VLCAD−/− mice, which mimic to some extent the human cardiac phenotype. Mice were sacrificed in the fed or fasted state after receiving for two weeks a chow or a high-fat diet (HFD), the latter condition being known to worsen symptoms in human VLCADD. Compared to their littermate counterparts, HFD/fasted VLCAD−/− mouse hearts displayed the following lipid alterations: (1) Lower LC, but higher VLC-acylcarnitines accumulation, (2) higher levels of arachidonic acid (AA) and lower docosahexaenoic acid (DHA) contents in glycerophospholipids (GPLs), as well as (3) corresponding changes in pro-arrhythmogenic AA-derived isoprostanes and thromboxane B2 (higher), and anti-arrythmogenic DHA-derived neuroprostanes (lower). These changes were associated with remodeling in the expression of gene or protein markers of (1) GPLs remodeling: higher calcium-dependent phospholipase A2 and lysophosphatidylcholine-acyltransferase 2, (2) calcium handling perturbations, and (3) endoplasmic reticulum stress. Altogether, these results highlight global lipid dyshomeostasis beyond FAO in VLCAD−/− mouse hearts, which may set conditions predisposing the hearts to calcium mishandling and endoplasmic reticulum stress and thereby may contribute to the pathogenesis of arrhythmias in VLCADD in mice as well as in humans.

Cardiac Rhabdomyomas as a Cause of Neonatal Arrhythmias.

Cardiac Rhabdomyomas as a Cause of Neonatal Arrhythmias.

Cardiac Arrhythmias Requiring Electric Countershock during the Neonatal Period-A Systematic Review.

In neonates, cardiac arrhythmias are rare. Electric countershock therapy is an effective alternative to drug therapy for neonatal arrhythmias. There are no randomized controlled studies investigating electric countershock therapy in neonates. To identify all studies and publications describing electric countershock therapy (including defibrillation, cardioversion, and pacing) in newborn infants within 28 days after birth, and to provide a comprehensive review of this treatment modality and associated outcomes. For this systematic review we searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and Cumulative Index to Nursing and Allied Health Literature (CINAHL). All articles reporting electric countershock therapy in newborn infants within 28 days after birth were included. In terms of figures, 113 neonates who received electric countershock due to arrhythmias were reported. Atrial flutter (76.1%) was the most common arrhythmia, followed by supraventricular tachycardia (13.3%). Others were ventricular tachycardia (9.7%) and torsade de pointes (0.9%). The main type of electric countershock therapy was synchronized cardioversion (79.6%). Transesophageal pacing was used in twenty neonates (17.7%), and defibrillation was used in five neonates (4.4%). Electric countershock therapy is an effective treatment option in the neonatal period. In atrial flutter especially, excellent outcomes are reported with direct synchronized electric cardioversion.

A Prospective Evaluation of Arrhythmias in a Large Tertiary Neonatal Intensive Care Unit.

Arrhythmias in the neonatal period are common and can be classified as bradyarhythmias and tachyarrhythmias and as benign or non-benign. Neonatal arrhythmias are further differentiated between those with abnormalities in generation (non-sinus) and those with abnormalities in propagation. Because the neonatal myocardium is immature and operates at the peak of the Starling curve, significant changes in heart rate can result in a decline in cardiac output and compromise end-organ perfusion. This is especially true for premature neonates, those critically ill, or those with concomitant congenital heart disease. While sustained arrhythmias are frequently witnessed and recorded in tertiary neonatal intensive care units (NICU) very little data exist on the observance of non-sustained brady- or tachyarrhythmias in this cohort. No prospective study has been performed on all neonates admitted to a large tertiary NICU throughout their entire stay. The purpose of this study was to prospectively evaluate the prevalence and type of arrhythmias in a large NICU population from admission to discharge. All neonates admitted to the NICU at Inova Children's Hospital at Inova Fairfax Medical Campus between January 1, 2021 and April 1, 2021 were prospectively evaluated from admission to hospital discharge via continuous bedside monitoring reviewed every 24h. Concerning telemetry strips were reviewed by two team members as well as the senior electrophysiologist. Two-hundred and one neonates (mean gestational age = 344/7weeks) were enrolled in the study. Admission length ranged from 1 to 195days (total of 5624 patient days, median 16days). Overall, 68% (N = 137) of admissions had one or more arrhythmias, the most common of which was sinus tachycardia (65%, N = 130), followed by sinus bradycardia (30%, N = 60). Clinically relevant arrhythmias were diagnosed in 6.5% of neonates. During the study period there were four deaths, none of which were directly attributable to a primary arrhythmia. Approximately 68% of neonates exhibited at least one arrhythmia. Although the vast majority of these arrhythmias were benign, clinically relevant arrhythmias were observed in 6.5%. Patients admitted to the NICU appear to have a relatively high burden of benign arrhythmias, but a relatively low burden of pathologic arrhythmias.

Association Between Neonatal Arrhythmia and Mortality and Recurrence: A Retrospective Study.

ObjectiveThe aim of the present study was to explore the association between neonatal arrhythmia (NA) and mortality and recurrence.MethodsA single-center, retrospective study was performed between January 1, 2015, and December 31, 2019. Neonates with NA were eligible and divided into either benign or non-benign groups. The primary outcomes were mortality and recurrence within 2 to 6 years.ResultsNA was diagnosed in 189 patients (0.39%) after screening 47,911 hospitalized neonates, and 10 of them did not finish the follow-up. Finally, 179 neonates were included into the final analysis (58 in the non-benign NA and 121 in the benign NA groups). The incidences of death and recurrence for NA were 5.59% (10/179) and 18.44% (33/179). Compared with neonates with benign NA, those neonates with non-benign NA were shown higher rates of death (13.79% vs. 1.65%; odds ratio [OR], 5.73; 95% confidence interval [CI], 1.07–31.01; p = 0.04) and recurrence (44.83% vs. 5.79%; OR, 8.49; 95% CI, 3.12–23.08; p < 0.001).ConclusionsNeonates with non-benign NA were shown higher rates of death and recurrence when compared with benign NA. Because of high recurrence, more attention was needed in neonates with non-benign NA after discharge.

Differential hERG 1 subunit transcription mediates IKr inhibition by protons in human stem cell-derived cardiomyocytes

hERG 1 variants are linked with intrauterine fetal death (IUD) and sudden infant death syndrome (SIDS), yet little is known about the mechanistic contribution of hERG 1 in developing and immature cardiomyocytes. Extracellular acidosis inhibits cardiac hERG 1 current (IKr), and disrupts cardiac function. Acidosis is also believed to be a contributing factor in cases of SIDS. We hypothesized that acidosis preferentially inhibits IKr of the immature myocardium, which could promote neonatal arrhythmia and sudden infant death.

Clinical and genetic spectrum of neonatal arrhythmia in a NICU.

BackgroundNeonatal arrhythmia is a common complication that might be life-threatening or serious, but the genetic causes are unclear in most cases. The aim of this study is to investigate the genetic causes of neonatal arrhythmia in a NICU in China.MethodsNewborns who were diagnosed with arrhythmia during the neonatal period were enrolled from Children’s Hospital of Fudan University between January 1st 2016, and December 31st, 2019. A neonatal gene panel was performed for each infant.ResultsIn total, 98 neonatal infants with arrhythmia were enrolled. Fourteen genes and a copy number change were identified and classified as pathogenic/likely pathogenic in 22 patients (22.4%), including 4 genes related to syndrome, 4 related to conduction, 2 related to metabolism, 2 related to structure, 2 related to respiration and immunity, respectively, and trisomy 21. Altogether, 6 genes (6/14, 42.9%) caused original heart structure or conduction abnormalities, leading to arrhythmia. Infants with ventricular tachycardia or fibrillation, atrioventricular block and long-QT syndrome all had positive gene results. The gene positive rate among arrhythmic infants with congenital heart disease or severe heart failure was higher than that of infants without congenital heart disease or severe heart failure.ConclusionsThe genetic disorders associated with neonatal arrhythmia could be syndrome-, conduction-, metabolism-, and structure-related. Infants with non-benign arrhythmia, especially ventricular tachycardia or fibrillation, long-QT syndrome, or high-grade atrioventricular block, have a higher rate of genetic abnormalities and should undergo genetic sequencing. Neonates with hereditary arrhythmias may have a higher risk of congenital heart disease or heart failure.

Arrhythmias in Neonates and Infants at a Tertiary Care Center

BackgroundLimited data about arrhythmias in neonates and infants are coming out from the Middle East.ObjectivesTo evaluate different types of arrhythmias in neonates and infants at the American University of Beirut Medical Center (AUBMC), a tertiary care center in Lebanon, with the focus on the nature of arrhythmia, treatment modalities and relation to surgery.MethodsData were collected retrospectively from the hospital records. We included all neonates and infants presenting to AUBMC between 2013 and 2017. Collected data included: the type of arrhythmia, the treatment modality used and its success, the need for additional modes of treatment, the relationship to congenital heart diseases, and the cardiac surgeries performed.ResultsOf 16,346 subjects admitted to AUBMC between 2013 and 2017, 90 subjects developed arrhythmias that required medical intervention. The most frequent types of arrhythmias were supraventricular tachycardia (62.22%), junctional ectopic tachycardia (13.33%), complete heart block (7.78%), atrial flutter (5.56%), multifocal atrial tachycardia (3.33%), Wolf Parkinson White Syndrome (3.33%), non-sustained ventricular tachycardia (2.22%), sinus pause (1.11%), and premature ventricular contractions (1.11%). Bivariate analysis showed a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in terms of the type of arrhythmia developed, the presence of congenital heart defect, prematurity, and electrolyte disturbances (P-value <0.005). However, multivariate logistic regression showed no significant difference between the two groups after adjustment for the significant variables (P-value > 0.05).ConclusionThere is a significant difference between arrhythmias not related to cardiac surgery and arrhythmias related to cardiac surgery in neonates and infants at AUBMC. However, the difference disappears after adjusting for different variables.

An Intriguing Case of Neonatal Arrhythmia

In the fetal and early neonatal period, clinically significant arrhythmias are remarkably rare whose medical management has been an area of dilemma in terms of safety and efficacy. We present a case of a hemodynamically stable female neonate presenting to us with atrial tachycardia with morphology of atrial fibrillation (AF) and atrial flutter (AFl). After a poor response to multiple antiarrhythmics, direct current cardioversion (DCC) was the final solution. Short-term maintenance therapy with oral propranolol was given with no recurrence. Hence, stepwise approach to infants with AFl can lead to an excellent prognosis with a low risk of recurrence.

Neonatal Arrhythmia

Arrhythmias are seldom observed in the newborn period and rarely lead to serious consequences. Because they may be a continuation of fetal arrhythmias, newborn arrhythmias are different from those occurring at later ages. Here we describe a case of a newborn presented with tachycardia at birth. A female baby of 1950 grams born by emergency cesarean section for fetal distress at 36 weeks of gestation. Fetal tachycardia of 251 bpm was detected prenatally. Electrocardiography showed supraventricular tachycardia (SVT). Hematological and biochemical tests done were within normal limits. Echocardiography revealed normal anatomy with severe tachycardia, dilated chambers with moderate to severe TR with moderately reduced ventricle function. For persisting SVT intravenous adenosine was administered with no significant decrease in heart rate, then continuous intravenous amiodarone infusion was started resulting in a transient decrease in heart rate, however again increased, hence baby was started on intravenous digoxin which responded well. Repeated echocardiography showed normal cardiac chambers and function. Baby was discharged on maintenance oral digoxin and was gradually weaned and stopped after 12 months of age. Neonatal arrhythmias is not an uncommon condition in newborns, however it should be early recognized and evaluated for a better outcome of the baby. Although the frequency of arrhythmias in the newborn period is not high, SVT are the most frequently observed arrhythmias in this period.

PROGNOSIS OF INDIVIDUAL RISK OF HEART RHYTHM DISTURBANCES AND CONDUCTIVITY IN NEWBORNS IN THE EARLY NEONATAL PERIOD

Background. Neonatal arrhythmias, for the most part, have a good prognosis for recovery. However, they can also have an adverse course and lead to the development of life-threatening conditions. Therefore, it is important to search for earlier markers of myocardial lesion, diagnostic criteria and predictors of arrhythmias. Purpose. Improvement of diagnosis and prediction of the risk of cardiac arrhythmias and conduction in newborns in the early neonatal period by identifying factors that play a role in the prediction of neonatal arrhythmias. Subjects &amp; Methods. The study involved 76 newborns. Group 1 included 57 infants with arrhythmias according to Holter monitoring, Group 2 included 19 infants without arrhythmias. The study implied a comparison of history data, laboratory and instrumental findings, levels of troponin I and copeptin. To predict the development of neonatal arrhythmias, logistic regression analysis was performed. The quality of the model was tested using the Percent Concordant (PC). Quality Score was evaluated by R2 Nigelkerke. Model adequacy was estimated using the Hosmer-Lemeshow test. Results. The study showed that the factors that can influence the development of arrhythmias in the early neonatal period are the level of umbilical cord blood, the levels of troponin I, copeptin, GGT, assessment of Apgar scale in the 1st and 5th minutes, asphyxia at birth, indices of wave R amplitude in V3 and V5 of chest leads, ST segment deviation from the isoline according to standard surface ECG, QTc levels and mean daily maximum, minimum heart rate according to Holter monitoring. Conclusions. Predictors of neonatal arrhythmias development are indicators of laboratory-instrumental parameters of cardiovascular system status, troponin I level above 0.29 ng/ml and copeptin level above 0.1 ng/ml.

CARDIAC ARRHYTHMIAS IN NEONATES: PROBLEMS IN DIAGNOSTICS AND TREATMENT

Problems of diagnosis of neonatal arrhythmias, the main types of rhythm disorders in newborns, the modern approaches to the treatment of arrhythmias in the fetus and newborn are discussed in the article.

Antenatal Therapy for Fetal Supraventricular Tachyarrhythmias: Multicenter Trial

BackgroundStandardized treatment of fetal tachyarrhythmia has not been established. ObjectivesThis study sought to evaluate the safety and efficacy of protocol-defined transplacental treatment for fetal supraventricular tachycardia (SVT) and atrial flutter (AFL). MethodsIn this multicenter, single-arm trial, protocol-defined transplacental treatment using digoxin, sotalol, and flecainide was performed for singleton pregnancies from 22 to <37 weeks of gestation with sustained fetal SVT or AFL ≥180 beats/min. The primary endpoint was resolution of fetal tachyarrhythmia. Secondary endpoints were fetal death, pre-term birth, and neonatal arrhythmia. Adverse events (AEs) were also assessed. ResultsA total of 50 patients were enrolled at 15 institutions in Japan from 2010 to 2017; short ventriculoatrial (VA) SVT (n = 17), long VA SVT (n = 4), and AFL (n = 29). One patient with AFL was excluded because of withdrawal of consent. Fetal tachyarrhythmia resolved in 89.8% (44 of 49) of cases overall and in 75.0% (3 of 4) of cases of fetal hydrops. Pre-term births occurred in 20.4% (10 of 49) of patients. Maternal AEs were observed in 78.0% (39 of 50) of patients. Serious AEs occurred in 1 mother and 4 fetuses, thus resulting in discontinuation of protocol treatment in 4 patients. Two fetal deaths occurred, mainly caused by heart failure. Neonatal tachyarrhythmia was observed in 31.9% (15 of 47) of neonates within 2 weeks after birth. ConclusionsProtocol-defined transplacental treatment for fetal SVT and AFL was effective and tolerable in 90% of patients. However, it should be kept in mind that serious AEs may take place in fetuses and that tachyarrhythmias may recur within the first 2 weeks after birth.

Antenatal Antiarrhythmic Treatment for Fetal Tachyarrhythmias: A Prospective Multicentre Trial

Background: Standardized treatment of fetal supraventricular tachycardia (SVT) and atrial flutter (AFL) has not been established. The aim of this study was to evaluate the safety and efficacy of protocol-defined transplacental treatment for fetal SVT and AFL. Methods: In this multicentre single-arm trial (UMIN Clinical Trials Registry number 000004270), protocol-defined transplacental treatment using digoxin, sotalol, and flecainide was performed for singletons from 22 to <37 weeks of gestation with sustained fetal SVT or AFL ≥180 beats per minute. The primary endpoint was resolution of fetal tachyarrhythmia. Secondary endpoints were fetal death, preterm birth, neonatal arrhythmia, and neonatal survival. Maternal, fetal, and neonatal adverse events (AEs) were evaluated. Findings: A total of 50 participants were enrolled and treated at 15 institutions in Japan from October 2010 to January 2017. They had short VA SVT (n=17), long VA SVT (n=4), and AFL (n=29). One participant with AFL was excluded due to withdrawal of consent. Fetal tachyarrhythmia resolved in 89·8% (44 of 49) of cases overall and 75·0% (3 of 4) of cases with fetal hydrops. Preterm births occurred in 20·4% (10 of 49) of participants. Maternal AEs were observed in 78·0% (39 of 50) of pregnant women. Severe AEs occurred in one mother and four fetuses, resulting in discontinuation of protocol treatment in four participants. Two fetal deaths occurred, mainly due to heart failure. No neonatal deaths occurred. Neonatal tachyarrhythmia was observed in 31·9% (15 of 47) of participants within 2 weeks after birth, except for one neonate with SVT. Interpretation: Protocol-defined transplacental treatment for fetal SVT and AFL was effective and tolerable in 90% of participants. However, it should be kept in mind that severe AEs may take place in fetuses and that recurrence of tachyarrhythmias may happen within 2 weeks after birth. Clinical Trials Number: UMIN Clinical Trials Registry number 000004270 Funding Statement: This work was supported by a grant from the Ministry of Health, Labor and Welfare of Japan (Health and Labour Science Research Grants for Clinical Research for New Medicine) (H19-009, H23-004), and in part by a grant from the Takeda Science Foundation (J042) and Tsuchiya Foundation (J151). Declaration of Interests: All authors declare no competing interests. Ethics Approval Statement: The Institutional Review Board of the National Cerebral and Cardiovascular Center of Japan.

Unraveling the causes of arrhythmias in very-long chain acyl-CoA (VLCAD) deficiency through the combined use of non-targeted lipidomic and molecular analyses in a mouse model

VLCAD catalyses the first reaction of mitochondrial fatty acids (FA) β-oxidation. Inherited VLCAD deficiency predisposes to severe neonatal arrhythmias whose pathophysiology is not fully understood. We hypothesized that VLCAD deficiency disrupts cardiac lipid homeostasis, which could contribute to arrhythmia. Our study model is the VLCAD null mouse (VLCAD −/− ), which is known to develop a prolonged QT interval and ventricular arrhythmias. Mice were fed a chow or high fat (HF) diet, the latter being known to worsen the cardiac phenotype in VLCAD deficiency. Non-targeted lipidomic profiling of heart tissues was achieved using liquid chromatography-mass spectrometry (LC-QTOF). The expression of genes or proteins involved in polyunsaturated FA synthesis, phospholipid (PL) remodeling, endoplasmic reticulum (ER) stress and calcium handling were assessed using RT-qPCR or Western blotting. Compared to their littermate counterparts, VLCAD −/− mouse hearts displayed alterations in the FA composition of PL characterised by an increase in arachidonic acid and a decrease in docosahexaenoic acid, a profile that was worsened with the HF diet. These changes in PL composition were associated with diet-dependent increased expression of gene or protein markers for (1) PL remodeling, especially the calcium-dependent phospholipase A2 and the lysophosphatidylcholine-acyltransferase 2, (2) ER stress, namely CHOP and GRP78, and (3) calcium handling, namely SERCA2a and phospholamban (PLB). In contrast, the phosphorylated form of PLB (Ser16) and RyR2 (Ser2808) was decreased. Altogether, results from this study highlight perturbations in PL remodeling in VLCAD −/− mouse hearts, which are associated with ER stress and alterations in proteins involved in calcium handling and exacerbated by a HF diet. These perturbations represent novel potential mechanisms, which could contribute to the pathogenesis of arrhythmias in VLCAD −/− mice as well as in humans.

Neonatal complex arrhythmias possibly related to a TTN mutation

We describe a neonate born with complex arrhythmias that included concurrent atrial and ventricular tachycardias. Genetic testing demonstrated a mutation in the TTN gene, which codes for titin, a large protein found in striated muscle sarcomeres. The complex arrhythmias were successfully treated with amiodarone and flecainide. The patient remains asymptomatic with normal biventricular function. We speculate that the complex arrhythmias and TTN gene mutation may be related.