Multifocal Atrial Tachycardia Research Articles

MULTIFOCAL ATRIAL TACHYCARDIA AND HYPERTROPHIC CARDIOMYOPATHY IN THREE PATIENTS WITH COSTELLO SYNDROME

Abstract Introduction Costello syndrome is a rare disease, caused by mutation of the HRAS gene, associated with intellectual disability, growth retardation, facial dimorphisms. Cardiac abnormalities, mainly cardiac hypertrophy and multifocal atrial tachycardia, are present in 1/3 of patients. Clinical Cases From 2019 to 2023, 3 newborns with Costello syndrome came under our observation. M.M. showed respiratory distress, hypotonia and dysmorphic notes; genetic analysis highlighted the pathogenic variant c.64C>A (p.Gln22Lys). On the echocardiogram, septal hypertrophic cardiomyopathy was found with left outflow obstruction and mitral insufficiency. Therapy with propranolol was undertaken. Holter ECG never revealed arrhythmias. At the last check–up, SIV hypertrophy, continent mitral valve, free left ventricular outflow. The second patient, O.L., arrived at 10 days of age following a run of supraventricular tachycardia. He had bilateral clubfoot and facial dimorphisms. The echocardiogram was normal. On Holter ECG atrial tachycardia interrupted by rare sinus beats. Therapy with flecainide was undertaken, without benefit. Subsequently, was undertaken amiodarone, then associated with digitalis. She was discharged with satisfactory control of the average ventricular rate, but later due to the appearance of chaotic atrial arrhythmia, propranolol was added; on the Holter ECG in triple therapy, periods of sinus rhythm alternating with short episodes of atrial tachycardia were observed. Genetic analysis revealed the pathogenic variant c.34G>A, p.(Gly12Ser) of the HRAS gene. The third patient, F.A., presented atrial tachycardia. Flecainide therapy had transient benefit. Subsequently propranolol was added, without benefit. Therapy with amiodarone was initiated. Transesophageal electrophysiological study demonstrated multifocal atrial tachycardia, unresponsive to overdrive pacing. Partial control of the average ventricular rate was achieved in triple therapy. On the echocardiogram, mild concentric hypertrophy and dysplastic pulmonary valve. Genetic testing detected the c.35G>C, p(Gly12Ala) variant of the HRAS gene. Conclusions Costello syndrome requires cardiac monitoring for the possible presence of multifocal atrial tachycardia and hypertrophic cardiomyopathy. Arrhythmia, which can also occur independently of hypertrophy, can be self–limited in the first months of life with aggressive pharmacological treatment but can persist or worsen in ¼ of patients.

HRAS-Mutant Cardiomyocyte Model of Multifocal Atrial Tachycardia.

Germline HRAS gain-of-function pathogenic variants cause Costello syndrome (CS). During early childhood, 50% of patients develop multifocal atrial tachycardia, a treatment-resistant tachyarrhythmia of unknown pathogenesis. This study investigated how overactive HRAS activity triggers arrhythmogenesis in atrial-like cardiomyocytes (ACMs) derived from human-induced pluripotent stem cells bearing CS-associated HRAS variants. HRAS Gly12 mutations were introduced into a human-induced pluripotent stem cells-ACM reporter line. Human-induced pluripotent stem cells were generated from patients with CS exhibiting tachyarrhythmia. Calcium transients and action potentials were assessed in induced pluripotent stem cell-derived ACMs. Automated patch clamping assessed funny currents. HCN inhibitors targeted pacemaker-like activity in mutant ACMs. Transcriptomic data were analyzed via differential gene expression and gene ontology. Immunoblotting evaluated protein expression associated with calcium handling and pacemaker-nodal expression. ACMs harboring HRAS variants displayed higher beating rates compared with healthy controls. The hyperpolarization activated cyclic nucleotide gated potassium channel inhibitor ivabradine and the Nav1.5 blocker flecainide significantly decreased beating rates in mutant ACMs, whereas voltage-gated calcium channel 1.2 blocker verapamil attenuated their irregularity. Electrophysiological assessment revealed an increased number of pacemaker-like cells with elevated funny current densities among mutant ACMs. Mutant ACMs demonstrated elevated gene expression (ie, ISL1, TBX3, TBX18) related to intracellular calcium homeostasis, heart rate, RAS signaling, and induction of pacemaker-nodal-like transcriptional programming. Immunoblotting confirmed increased protein levels for genes of interest and suppressed MAPK (mitogen-activated protein kinase) activity in mutant ACMs. CS-associated gain-of-function HRASG12 mutations in induced pluripotent stem cells-derived ACMs trigger transcriptional changes associated with enhanced automaticity and arrhythmic activity consistent with multifocal atrial tachycardia. This is the first human-induced pluripotent stem cell model establishing the mechanistic basis for multifocal atrial tachycardia in CS.

Multifocal Atrial Tachycardia Transitioning to Atrial Fibrillation in an Octogenarian

Abstract Multifocal atrial tachycardia (MAT) is an arrhythmia frequently seen in the elderly whose prevalence increases with aging. These arrhythmias may eventually lead to more chaotic arrhythmias such as atrial fibrillation (AF) and flutter. MAT is frequently mistaken for AF in electrocardiogram (ECG). The importance of differentiating MAT from AF is that the former requires no anticoagulation and, therefore, avoids the risks associated with their administration. It is also important to realize that the elderly have multiple conditions such as senile tremors and Parkinson’s disease which may cause mechanical movement artifacts in resting ECGs mimicking cardiac arrhythmias leading to incorrect interpretation of ECGs. Educating physicians about the electrocardiographic appearance of atrial dysrhythmias and the recognition of the confounding artifacts can prevent unnecessary use of treatment which could potentially cause adverse effects in the patient.

Case study: Multifocal atrial tachycardia during cataract surgery: to operate or not to operate

Case study: Multifocal atrial tachycardia during cataract surgery: to operate or not to operate

PO-05-147 RIGHT ON Q: WIDE-COMPLEX TACHYCARDIA IN SETTING OF DEXTROPOSITION

Dextroposition is a rare cardiac malformation defined as rightward cardiac displacement with leftward apex, vs. dextrocardia, which is rightward base-axis orientation. We report the second known case of dextroposition with accessory pathway, presenting as preexcited atrial tachycardia. Abnormal anatomy complicates ECG localization and pathway ablation. N/A N/A A 50-year-old woman was admitted with respiratory distress due to EBV infection. Chest X-ray showed right-sided heart. A month later, she presented in wide-complex tachycardia, rate 205 bpm. She was cardioverted after minimal response to procainamide/adenosine. Post-cardioversion ECG showed short PR interval and preexcitation, confirming presence of accessory pathway. However, the wide-complex tachycardia had morphology identical to baseline, supporting preexcited atrial tachycardia over AVRT. Despite X-ray findings and reverse R-wave progression in precordial leads, presence of left axis deviation and initial negative deflection in aVR argued against dextrocardia. Moreover, aVR had negative T- and P-waves, findings associated with levocardia. Thus, dextroposition was suspected. Millstein and Arruda criteria suggested posteroseptal accessory pathway, but no data on their applicability in right-sided heart exist. EP study was performed. Eccentric VA conduction was noted. Earliest activation was at proximal coronary sinus. During isoproterenol infusion, patient went into atrial tachycardia, cycle length 420ms. Multiple AT foci were identified, including at right atrial appendage and tricuspid annulus. During ablation, patient developed atrial fibrillation with preexcited RR <250ms, confirming high-risk accessory pathway. Given numerous AT foci and high risk, it was decided to focus on pathway over tachycardia sites. Pathway was successfully ablated at ostia of coronary sinus and middle cardiac vein. One prior case of accessory pathway ablation in dextroposition has been reported. This patient had left lateral pathway and multiple congenital abnormalities including lung hypoplasia. While our patient was found to have multifocal atrial tachycardia, she had no clinical or radiographic lung disease. ECG changes in dextroposition are less predictable than in dextrocardia; they vary with cardiac rotation, axis position, and lead position. Comorbid accessory pathway is rare; ECG-anatomy relationship is ill-defined. Structural abnormalities pose individual challenges during electrophysiologic procedures.

Catheter ablation for supraventricular arrhythmias in adults with congenital heart disease: Recurrence rates and predictors of acute procedural success

AimsTo define the cohort of adult congenital heart disease (ACHD) patients undergoing catheter ablation for supraventricular arrhythmia in a large tertiary centre, characterise outcomes, and determine factors associated with arrhythmia recurrence. MethodsSingle centre retrospective study of all catheter ablations for atrial arrhythmias in ACHD patients between September 2014 and October 2021. Patients were identified using a field search through a centralised database. Pre-specified clinical and procedural data of interest, and time from ablation to recurrence, were determined. Cox regression analyses were used to determine potential predictors of acute procedural success and arrhythmia recurrence. ResultsCardiac ablation for supraventricular arrhythmia was undertaken in 142 cases across 100 unique patients (median age 41, interquartile range 31–52), with 70 (49%) cases treated for macro-reentrant atrial tachycardia, 16 (11%) for focal atrial tachycardia, 19 (13%) for multifocal atrial tachycardia, 17 (12%) for atrial fibrillation, 7 (5%) for atrioventricular nodal reentrant tachycardia, and 8 (6%) for atrioventricular reentrant tachycardia; and 68 cases (48%) had recurrent arrhythmia with a median time to recurrence of 800 days. Multivariable analysis identified acute procedural success as an independent predictor of freedom from arrhythmia, and ablation for persistent atrial fibrillation as an independent predictor for recurrence of arrhythmia. ConclusionCatheter ablation for supraventricular arrhythmia in ACHD patients is safe and effective, with most patients achieving multiple arrhythmia-free months. Procedural success and arrhythmia mechanism are important predictors of recurrence.

“ECG AND ECHOCARDIOGRAPHIC FINDINGS IN CHRONIC OBSTRUCTIVE PULMONARY DISEASE”

Background: Chronic Obstructive Pulmonary Disease (COPD) which encompasses both chronic bronchitis and emphysema is one of the commonest respiratory condition of adults in the developing world.Aim:To study the electrocardiographic and echocardiographic changes in chronic obstructive pulmonary disease. Methods: All COPD patients above 30 years of age, diagnosed clinically and satisfying the spirometric criteria were included in the study. All patients were subjected to both 2 D and Doppler Echocardiogram and pulmonary artery pressure measured. - Pulmonary function test was done using spirometry. Results: ECG abnormalities suggestive of pulmonary hypertension (Right ventricular hypertrophy) was found in more than half of these cases. Poor progression with R/S is &lt; 1 was found in 12 cases, right ventricular strain patterns like ST depression in II, III AVF and T wave inversion was found in 7 and 6 cases respectively, low voltage QRS in 5 cases. Other rare ECG abnormalities like lead I sign and SI, S II, S III was found in 2 and 1 cases respectively. Rhythm abnormalities like ventricular ectopics, RBBB are found in 2 cases and multi focal atrial tachycardia in 1 case. Conclusion: COPD is commonly seen in persons above 40 years of age ie., in the middle and old aged people. - It is more common among males. - It is associated with the smoking pattern of more than 20 pack years

Value of a 12-Lead Electrocardiogram for Assessing P Waves.

Scenario: The rhythm strip below was printed from the bedside monitor of a 71-year-old man admitted to the intensive care unit for hypoxemic respiratory failure, fluid overload, and septic shock. The patient’s history includes coronary artery disease, hypertension, diabetes, paroxysmal atrial fibrillation after successful cardioversion (prescribed at-home apixaban), alcoholic cirrhosis, heart failure (ejection fraction, 50%), and chronic obstructive pulmonary disease (COPD). When this electrocardiogram (ECG) was generated, his blood pressure was 119/63 mm Hg, heart rate was 95/min, and oxygen saturation was 97% while receiving mechanical ventilation with a fraction of inspired oxygen of 0.8. The nurse noted that the rhythm looked like either a heart block or multifocal atrial tachycardia (MAT) and decided to record a 12-lead ECG (see next page). What is your interpretation?Atrial flutter (AFL) with 3:1 conduction with a ventricular rate of ~100/min and right bundle branch block (RBBB).Atrial flutter is common in patients with hypertension, diabetes, COPD, alcohol misuse, and atrial fibrillation (risk factors in this scenario) and is typically initiated or terminated by a premature complex (atrial or ventricular) or rapid atrial pacing. When a premature stimulus excites an area in the atrium, it travels in a single stable reentry circuit (either clockwise or counterclockwise) that is long enough to allow initially depolarized myocardial tissue to recover and then be capable of depolarizing again owing to the reentered stimulus. This mechanism can be seen in this example, particularly in leads III and aVF, as regular, uniform flutter waves (or F waves). The typical atrial rate for AFL is 200-350/min and is characterized by the absence of an atrial diastolic interval, as is seen in sinus rhythm.The rhythm strip displayed only leads II and V1 and showed upright P waves in V1 with various PR intervals, which could be confused with third-degree heart block. In lead II, the P wave is negative, suggesting a junctional rhythm with retrograde conduction of the atria. However, the sharp negative P wave in lead II raises the suspicion of AFL, which was confirmed on the 12-lead ECG. The unique feature of F waves (ie, “sawtooth” pattern) associated with AFL can be seen clearly in leads III and aVF. The F waves that are negative in the inferior leads but positive in V1 indicate the AFL is moving in a counterclockwise direction, which is most common (~75% of cases). The flutter waves should not be confused with MAT, which typically exhibits at least 3 different P-wave morphologies and is irregular because of multiple focal sites of atrial impulse formation. In contrast, AFL is a self-sustaining macroreentrant atrial arrhythmia without focal sites of impulse formation. The ventricular rate in AFL is usually a multiple of the FF interval. In this case, the F waves occur at a rate of 300/min and result in a ventricular rate of ~100/min and can be slightly irregular.Left ventricular hypertrophy in the presence of RBBB can be examined by using an S wave >2 mm in V1 or an R wave >15 mm in V5 or V6, both of which are absent on this ECG.Clinical management is focused on converting AFL to normal sinus rhythm, which will reduce the heart rate and prevent embolic stroke. In this case, the cardiology service was consulted, and ibutilide, an antiarrhythmic, was prescribed with a return to normal sinus rhythm. The patient’s anticoagulant was changed to clopidogrel, an antiplatelet. Given this patient’s underlying risk factors and the risk of prolonging QT with ibutilide, the QT interval should be closely monitored to prevent torsades de pointes. The patient's hospital course was complicated by continued respiratory distress and acute alcohol withdrawal. He was later transferred to the step-down unit.

Progress of Pathogenesis in Pediatric Multifocal Atrial Tachycardia.

Multifocal atrial tachycardia (MAT) is defined as irregular P-P, R-R, and P-R intervals, isoelectric baseline between P waves, and ventricular rate over 100 beats/min. Although the prognosis of pediatric MAT in most patients is favorable, adverse outcomes of MAT have been reported, such as cardiogenic death (3%), respiratory failure (6%), or persistent arrhythmia (7%), due to delayed diagnosis and poorly controlled MAT. Previous studies demonstrated that pediatric MAT is associated with multiple enhanced automatic lesions located in the atrium or abnormal automaticity of a single lesion located in the pulmonary veins via multiple pathways to trigger electrical activity. Recent studies indicated that pediatric MAT is associated with the formation of a re-entry loop, abnormal automaticity, and triggering activity. The occurrence of pediatric MAT is affected by gestational disease, congenital heart disease, post-cardiac surgery, pulmonary hypertension, and infectious diseases, which promote MAT via inflammation, redistribution of the autonomic nervous system, and abnormal ion channels. However, the pathogenesis of MAT needs to be explored. This review is aimed to summarize and analyze the pathogenesis in pediatric MAT.

Lewis Lead: Reveal the Hidden P Wave

Background. The Lewis lead configuration can help to detect atrial activity and its relationship to ventricular activity, so diagnosis can be achieved more accurately. With Lewis lead ECG, it will make easier to make a diagnosis, especially in identifying electrical activity in the atrium.&#x0D; Case Illustration. Case 1. A 61-year-old male with decreased consciousness et causa metabolic. From a standard 12-lead ECG, the P waves are difficult to identify, and at first glance it looks like atrial fibrillation. From the Lewis ECG in lead I, it appears that the QRS wave is always preceded by a P wave, with different morphologies (more than 3 forms), that showed as multifocal atrial tachycardia (MAT) with a heart rate of 120 beats / minute. Case 2. The 58-year-old male patient complained of typical ischemic chest pain and palpitations. A standard 12 lead ECG examination revealed a rhythmic tachycardia with a wide QRS wave at a rate of 210 beats / minute. From the Lewis ECG in lead I, we can see that the P waves that appear are not always followed by QRS. Thus, it can be seen that the AV dissociation is a VT so that VT management can be done immediately. Case 3. A 65-year-old male patient diagnosed with grade 5 CKD on dialysis. From a standard 12 lead ECG examination, a wide QRS wave with a P wave is obtained which is sometimes seen behind the QRS wave, making the diagnosis difficult to establish. From the Lewis ECG in lead I, it appears that the P wave always appears at the end of the QRS wave, so it can be seen that the rhythm from the ECG is derived from accelerated idioventricular rhythm with ventriculoatrial conduction.&#x0D; Conclusion. The accuracy of ECG interpretation is needed to determine the next treatment for the patient. Through the ECG examination with the Lewis lead method, the cardiac electrical activity will be more visible, so it will be very helpful in the interpretation of the ECG in cases that are not clear on the standard 12 lead ECG examination.

Successful Explantation of Berlin Heart Excor in Two Young Children.

Berlin Heart EXCOR ventricular assist device (VAD) implantation in children is widely used as bridge-to-heart transplantation. Berlin left ventricular assist device (LVAD) support as a bridge to recovery is rare. There is a scarcity of literature describing systematic evaluation in pediatric VAD explantation. Patient 1. A 3 month old boy presented with acute heart failure secondary to myocarditis. An echocardiogram demonstrated severely depressed left ventricular function. He required ECMO cannulation and was decannulated 11 days later. He continued to be hemodynamically unstable and required Berlin LVAD implantation with the intent to bridge to transplantation. Patient 2. A 3 month old boy presented initially with a heart rate of 250 beats/min and an electrocardiogram showed multifocal atrial tachycardia. An echocardiogram showed severely decreased left ventricular function. He was placed on ECMO due to unstable hemodynamics. He did not tolerate ECMO decannulation due to persistent chaotic atrial rhythm and underwent Berlin LVAD implantation with the intent to bridge to transplantation. After both patients showed evidence of myocardial recovery, they underwent a weaning protocol that includes: screening, trial-off with echocardiography, and trial-off in the catheterization suite. Our patients met the criteria and underwent successful explantation. Explantation of VAD can be successfully performed even in young children with appropriate candidate selection and a multidisciplinary and systematic approach.

Baseline electrocardiographic findings as predictors of outcome in hospitalized patients with COVID-19

Introduction The impact of coronavirus disease-2019 (COVID-19) on the heart is variable, but cardiac damage is associated with a bad prognosis. The mechanism behind the association between COVID-19 and cardiovascular diseases is not clear, but most of these patients reported with diseased immune system.Patients and methods This retrospective study included 70 hospitalized (moderate and severe) RT-PCR-positive COVID-19 patients. Data were retrieved from Mansoura University quarantine records from October 2020 to December 2020. The 12-lead channel conventional ECG collected at the first time after the patients were admitted to the hospital was used.Results About 94.3% of studied patients were in sinus rhythm, premature ventricular contractions were found in 2.9%. Atrial fibrillation was present in 4.3% and multifocal atrial tachycardia in 1.4%. Ischemic changes were found in 25.7% of the studied patients. About 14.3% had conduction defects. In this study, ECG ischemic changes only were significantly correlated with progress of respiratory support needed during hospitalization (44.4% of mechanically ventilated patients had ECG ischemic changes), mortality (P=0.04), and higher D-dimer level.Conclusion Baseline ECG ischemic changes associated with worse outcome of moderate and severe COVID-19 patients. Continuous monitoring of ECG changes in COVID-19 patients is recommended as it can provide an important assessment of COVID-19 severity.

Atrial electromechanical delay, neutrophil-to-lymphocyte ratio, and echocardiographic changes in patients with acute and stable chronic obstructive pulmonary disease.

Atrial electromechanical delay (AEMD) is the time interval between the beginning of P wave on surface electrocardiography and starting of the late diastolic wave on tissue Doppler imaging. We investigated the prolongation of AEMD, echocardiographic changes, and correlation of these findings with neutrophil-to-lymphocyte ratio (NLR) in patients with chronic obstructive pulmonary disease (COPD). The study consisted of 105 (49 females and 56 males; mean age: 65.1 ± 9) patients with COPD exacerbation and 104 (21 females and 83 males; mean age: 64.8 ± 9.6) stable COPD outpatients. Demographics, body mass index, pulmonary function tests, and transthoracic echocardiography of the patients were evaluated. Echocardiography was performed in the first 6 h for stable COPD outpatients and in the first 24 h for COPD exacerbation patients. Diameters of right ventricle (RV), left ventricle (LV) and left atrium, aortic root diameters, left ventricular ejection fraction (LVEF), Emax, Amax, Emax/Amax, tricuspid annular plane systolic excursion (TAPSE), Ea, Aa, Ea/Aa, Emax/Ea, and tricuspid regurgitation velocity (TRV) were evaluated. AEMD measurements were obtained from lateral/tricuspid, lateral/mitral, and septal annulus from apical four-chamber views with tissue Doppler imaging and corrected for heart rate. Complete blood count including NLR was also assessed. The mean age of patients in exacerbation period (65.1 ± 9) was higher than the stable group (64.8 ± 9.6). RV basal and mid diameters (P < 0.001), Amax (P < 0.001), Ea tricuspid (P = 0.040), Aa tricuspid (P < 0.001), TRV, and systolic pulmonary artery pressure (P < 0.001) were higher; TAPSE and tricuspid Emax/Amax (P < 0.001) were significantly lower in patients with COPD exacerbation. LV end-diastolic diameter (P = 0.002) and LVEF (P = 0.005), Emax/Amax mitral (P < 0.001), Ea/Aa mitral (P < 0.001), and Ea/Aa septal (P < 0.001) were significantly lower; Amax mitral (P = 0.002), Aa mitral (P < 0.001), Aa septal (P < 0.001), and systolic motion mitral (P = 0.011) were significantly higher in patients with exacerbation. AEMD lateral/tricuspid (P < 0.001), lateral/mitral (P < 0.001), and septal (P < 0.001) were significantly higher in patients with COPD exacerbation. Neutrophil and lymphocyte count (P < 0.001) and NLR (P = 0.003) were significantly higher in the acute group. A weak correlation of NLR with LV end-diastolic diameter (P = 0.003; r = 0.357), Emax/Ea mitral (P = 0.019; r = 0.285), Emax tricuspid (P = 0.045; r = -0.244), and systolic motion septal (P = 0.003; r = 0.352) was detected in patients with stable COPD. In COPD exacerbation patients, prolongation of AEMD intervals was determined. Acute period of COPD may trigger atrial dysrhythmias including atrial fibrillation and flutter, multifocal atrial tachycardia, premature beats, and both systolic and diastolic dysfunctions frequently.

Experience in the management of infants with multifocal atrial tachycardia

Purpose. To study the clinical course of multifocal atrial tachycardia (MAT) and to evaluate the effectiveness of antiarrhythmic therapy (AAT) in patients with onset of arrhythmia before the age of 1 year.Methods. The study included 15 children with primary registration of MAT at the age of 2.04±2.27 months, 4 of them - in utero. The follow-up period was 35.9±26.9 months (Me 29 months). All patients underwent laboratory monitoring, 12-lead ECG recording, 24-hour ECG monitoring, echocardiography at baseline and during time of observation.Results. Tachycardia was persistent in 80% of patients. Tachycardia-induced cardiomyopathy (TIC) was present in 7 (46%) patients. Structural heart disease was detected in 6 patients. The average heart rate at the onset of the disease was 157.9±23.78 bpm, the maximum - 256.7±35.84 bpm. Fourteen (93.3%) children received AAT. Seven patients were prescribed propranolol first, 6 - amiodarone, 1 - digoxin. Monotherapy was effective in 2 patients. Combined AAT was used in 12 patients, including three children with three drugs combination. No benefits were found for any of the drugs combinations. Stable sinus rhythm at the time of discharge was observed in 4 (28,6%) patients, sinus rhythm with atrial ectopic activity was registered in 2 of them; criteria for normosystole were achieved in 7 patients; in one child with TIC daytime tachysystole persisted despite three-component AAT, but echocardiography parameters improved. Arrhythmia was disappeared in 13 (86.6%) patients; the duration of arrhythmia in them from 1 to 15 months, duration of AAT - 1 ±7.5 months (Me 9.5 months). MAT persists in two patients with structural heart disease. One patient underwent radiofrequency ablation at the age of 5, with no effect. One patient had side effects from therapy that required correction. There were no lethal outcomes.Conclusion. MAT with a debut at the age of 1 year with timely prescribed treatment has a favorable course and a good prognosis, but the probability of AAT resistance is high. These cases require a long-term selection of therapy using various combinations of antiarrhythmic drugs. Heart rate control strategy can be sufficient to prevent the development of TIC.

Emery-Dreifuss muscular dystrophy presenting as a heart rhythm disorders in children

Abstract Introduction Emery-Dreifuss muscular dystrophy (EDMD) is an inherited muscle dystrophy often accompanied by cardiac abnormalities in the form of supraventricular arrhythmias, conduction defects, sinus node dysfunction. Cardiac phenotype typically arises years after skeletal muscle presentations, though, can be severe and life-threatening. The disease usually manifests during the third decade of life with elbow joint contractions and progressive muscle weakness and atrophy. Objective To present our clinical experience of diagnosis and treatment of arrhythmias in children with Emery-Dreifuss muscular dystrophy Materials and methods We enrolled 5 patients with different forms of EDMD (X-linked and autosomal dominant) linked to the mutations in EMD and LMNA genes, presented with early onset of cardiac abnormalities and no leading skeletal muscle phenotype. The predominant forms of cardiac pathology were atrial flutter, atrial fibrillation and conduction disturbances that progress over time. Clinical examination included physical examination, 12-lead electrocardiography, Holter ECG monitoring (HM), transthoracic echocardiography, neurological examination and biochemical and hormone tests. Also we performed CMR, electrophysiological study (EPS), treadmill test of some patients. One patient underwent an endomyocardial biopsy to exclude inflammatory heart disease. Target sequencing was performed using a panel of 108 or 172 genes Results We observed five patients with EDMD and cardiac debut during first-second decades of life: 3 with 1st subtype (variants in EMD gene) and 2 with 2nd subtype (variants in LMNA gene). All patients were males. The mean age of cardiac manifestation was 13,2±3,11 (from 9 to 16 y.o.). The mean follow-up period was 7,4±2,6 years. All patients presented with sinus node dysfunction and four out of five with AV conduction abnormalities. The leading arrhythmic phenotypes included various types of supraventricular arrhythmias: multifocal atrial tachycardia (AT) (n=4), premature atrial captures (PACs) (n=4), atrial flutter, (AF) (n=3), atrial fibrillation (AFib) (n=3) and AV nodal recurrent tachycardia (AVRNT). Heart rhythm disorders were the first manifestation in all three patients with 1st EDMD subtype. Radiofrequency ablation was performed in 2 patients, one of them received permanent pacemaker implantation. Conclusions In conclusion, while being the rare cases, heart rhythm disorders can represent the first and for a long time, the only clinical symptom of EDMD even in the pediatric group of patients. Therefore, thorough laboratory and neurological screening along with genetic studies, are of importance in each pediatric patient presenting with complex heart rhythm disorders of primary supraventricular origin to exclude EDMD or other neuromuscular disorders. Funding Acknowledgement Type of funding sources: None.

Frequency of Atrial Arrhythmias in the Patients With Chronic Obstructive Pulmonary Disease

Background: Chronic obstructive pulmonary disease (COPD) has been linked with various kind of cardiac arrhythmias. The risk of arrhythmias in patients with COPD has been driven by the stage and disease state, with a higher frequency of supraventricular tachycardia during exacerbations. Aim: To evaluate the frequency of atrial arrhythmias (which include atrial fibrillation, atrial flutter, and multifocal atrial tachycardia) in the patients who were suffering from COPD. Methods: It was a cross sectional analysis or prevalence study. This research was piloted in the Medicine Department, Medical Division IV, Services Hospital, Lahore. This research was ended in 365 days after endorsement of synopsis from 1st June, 2017 to 30th May 2018. Results: In our study, 111(46.25%) were in range 40-55 years of age while 129(53.75%) were in range 56-70 years of age, the calculated mean standard deviation was 56.23±8.19 years, 134(55.83%) were male and 106(44.17%) were females, 142(59.17%) between 1-2 years and 98(40.83%) had &gt;2 years of duration. Frequency of atrial arrhythmias in the patients who were suffering from COPD was recorded as 22(9.17%) having Atrial Fibrillation, 53(22.08%) had Atrial flutter and 31(12.92%) had Multifocal atrial tachycardia. Conclusion: Atrial arrhythmias are common findings in patients with COPD. So, it is very important for treating physicians that every patient having COPD, should undergo Electrocardiogram (ECG) for picking up the atrial arrhythmias. Keywords: Chronic obstructive pulmonary disease, atrial arrhythmias, frequency

Catheter ablation for atrial arrhythmias in adults with congenital heart disease: recurrence rates and predictors of acute procedural success

Abstract Funding Acknowledgements Type of funding sources: None. Background Heart rhythm disorders are an important cause of morbidity and emergency hospitalisation in patients with adult congenital heart disease (ACHD), and this is due to a combination of surgical scar, residual haemodynamic lesions, and cardiac chamber dilatation. The most effective available treatment is catheter ablation, although this can be extremely challenging owing to abnormal anatomy and problems accessing intra cardiac sites critical to the arrhythmia mechanism. However, outcomes of catheter ablation and analysis of factors which may predict recurrence of arrhythmia remain poorly defined. Purpose To define the cohort of ACHD patients undergoing catheter ablation for atrial arrhythmia in a large tertiary centre, characterise outcomes, and determine factors associated with arrhythmia recurrence. Methods Retrospective study of all catheter ablations for atrial arrhythmias in ACHD patients between April 13, 2016 and December 16, 2019 at our institution. Patients were identified using a field search through a centralised database; and pre-specified clinical and procedural data of interest, and time from ablation to recurrence were determined from the computerised electronic record. Binary logistical regression and cox regression analysis were used to determine potential predictors of acute procedural success and arrhythmia recurrence respectively. Results Among 90 patients (mean age 43 ± 15 years) who underwent catheter ablation for atrial arrhythmia, 39 (43%) were treated for macro-reentrant atrial tachycardia, 19 (21%) for focal atrial tachycardia, 9 (10%) for multifocal atrial tachycardia, 10 (10%) for atrial fibrillation, 7 (8%) for atrioventricular nodal reentrant tachycardia, and 6 (7%) for atrioventricular reentrant tachycardia. 35 (39%) of patients had "severe" complexity ACHD as per the Bethesda classification. 35 (39%) experienced recurrent arrhythmia with a median time to recurrence of 120 days. Age, gender, body mass index, complexity of congenital heart disease, and previous surgical repair were not identified as being significantly associated with recurrence, however univariate cox regression analysis showed a significantly longer time to recurrence in cases utilising electroanatomical mapping and demonstrating non-inducibility of arrhythmia in the lab post ablation (p &amp;lt; 0.001). There was 1 case of post-ablation bradycardia requiring pacemaker implantation, but no other complications. Conclusion Catheter ablation for atrial arrhythmia in ACHD patients is safe and effective, with a majority of patients achieving multiple arrhythmia-free months. Non-inducibility of arrhythmia post procedure and use of electroanatomical mapping are predictors of freedom from recurrence of atrial arrhythmia, suggesting effective characterisation and ablation of the arrhythmia mechanism is more important than the underlying substrate. These findings may aid management decisions for recurrent arrhythmia in ACHD patients.

Association between electrocardiographic features and mortality in COVID-19 patients.

BackgroundCardiovascular events have been reported in the setting of coronavirus disease‐19 (COVID‐19). It has been hypothesized that systemic inflammation may aggravate arrhythmias or trigger new‐onset conduction abnormalities. However, the specific type and distribution of electrocardiographic disturbances in COVID‐19 as well as their influence on mortality remain to be fully characterized.MethodsElectrocardiograms (ECGs) were obtained from 186 COVID‐19‐positive patients at a large tertiary care hospital in Northern Nevada. The following arrhythmias were identified by cardiologists: sinus bradycardia, sinus tachycardia, atrial fibrillation (A‐Fib), atrial flutter, multifocal atrial tachycardia (MAT), premature atrial contraction (PAC), premature ventricular contraction (PVC), atrioventricular block (AVB), and right bundle branch block (RBBB). The mean PR interval, QRS duration, and corrected QT interval were documented. Fisher's exact test was used to compare the ECG features of patients who died during the hospitalization with those who survived. The influence of ECG features on mortality was assessed with multivariable logistic regression analysis.ResultsA‐Fib, atrial flutter, and ST‐segment depression were predictive of mortality. In addition, the mean ventricular rate was higher among patients who died as compared to those who survived. The use of therapeutic anticoagulation was associated with reduced odds of death; however, this association did not reach statistical significance.ConclusionThe underlying pathogenesis of COVID‐19‐associated arrhythmias remains to be established, but we postulate that systemic inflammation and/or hypoxia may induce potentially lethal conduction abnormalities in affected individuals. Longitudinal studies are warranted to evaluate the risk factors, pathogenesis, and management of COVID‐19‐associated cardiac arrhythmias.

Delayed diagnosis of dilated thyrotoxic cardiomyopathy with coexistent multifocal atrial tachycardia: a case report

BackgroundThyroid storm (TS) is a rare but potentially life-threatening sequelae of untreated or undertreated hyperthyroidism. While TS frequently causes high-output heart failure, low-output heart failure related to dilated cardiomyopathy (DCM) is extremely rare. Tachycardia is a common clinical presentation of TS, and β1-selective blockers are the first-line agents for treating TS-associated tachycardia. However, given that β-blockers have negative chronotropic and negative inotropic effects, amiodarone may be safe and effective for the treatment of TS-induced tachyarrhythmia in patients with moderate to severe heart failure. While long-term amiodarone administration causes hypothyroidism, or less frequently, hyperthyroidism, little is known about the effects of short-term amiodarone administration on thyroid function.Case presentationA 31-year-old healthy woman presented with worsening dyspnoea. She was tachycardic with multifocal atrial tachycardia (MAT) of 184 beats/min, confirmed by electrocardiogram. Echocardiographic findings were consistent with DCM, with an ejection fraction of 20%. Thus, she was initially diagnosed with acute heart failure due to DCM with coexistent MAT. Tachycardia persisted despite cardioversion attempts and treatment with multiple anti-arrhythmic drugs. Consequently, she rapidly progressed to cardiogenic shock and respiratory decompensation, which required intubation and an intra-aortic balloon pump support. Moreover, the undiagnosed Graves' disease, lack of suspicion, and postponed analysis of thyroid function tests led to a delayed diagnosis of TS. Amiodarone, which was initiated for MAT, unexpectedly ameliorated thyrotoxicosis, resulting in a euthyroid state and the patient’s significantly improved condition and cardiac function. She was discharged on day 40. Finally, she underwent total thyroidectomy; thyroid pathology was consisting with Graves' disease. Her postoperative course was uneventful.ConclusionsHerein, we describe a case of delayed diagnosis of dilated thyrotoxic cardiomyopathy with coexistent MAT. The patient required intensive care due to the catastrophic sequelae and was successfully treated with amiodarone. This is the first case report of TS-associated MAT and highlights the clinical importance of high suspicion of TS in de novo heart failure with any tachyarrhythmia or DCM of unknown etiology and the potential effects of short-term amiodarone administration in the treatment of TS.

Atrial fibrillation in preterm neonates: A case study

Atrial fibrillation (AF) is rarely found in newborns and infants. It is usually associated with some underlying diseases and presents as tachyarrhythmia. Here, we describe a case of AF in a preterm neonate. Paroxysmal AF and multifocal atrial tachycardia had been observed in the postnatal dynamic electrocardiogram. Further investigations revealed patent foramen ovale, pulmonary disease, heart failure and potential viral myocarditis. After receiving antiarrhythmic therapy and supportive treatment, the neonate underwent successful cardioversion and showed favorable outcomes without any recurrence.