Background Accelerated idioventricular rhythm (AIVR) is a wide QRS complex dysrhythmia that, as far as pediatric population is concerned, occurs mostly in children with underlying systemic or heart disease. Its clinical course is thought to be typically benign in otherwise healthy children and treatment to be completely needless. Existing guidelines/recommendations are based entirely on cases that had low daily burden of AIVR, and those referring to treatment itself are very unspecific. Pharmacologic therapy has been mostly unsuccessful and catheter ablation as a way of treatment has been only sporadically reported. This article is a case report with a literature review that aims to practically separate the age groups into newborn and older children and to emphasize the different clinical outcomes of children with occasional and frequent AIVR. There are only a few cases so far describing undesirable outcomes of this condition, and most of these patients had high daily burden of AIVR. To be more specific, among 38 healthy children older than 1 year reported in total, 6 had undesirable outcomes, short-term in terms of developing malignant arrhythmia or long-term in terms of developing cardiomyopathy/heart failure. Case presentation An 11-year-old boy had been referred to our center for a workup of incidentally discovered wide-complex arrhythmia. He was asymptomatic, with no underlying cardiac or systemic diseases. Continuous heart rate monitoring detected AIVR during most time of monitoring. In 24-h Holter-ECG, wide QRS complexes accounted for 73%. With parental consent, we conducted an electrophysiological study accompanied by radiofrequent ablation of ectopic focus, which lead to an instantaneous sinus rhythm that continued during the entire follow-up. Conclusion AIVR is a rare dysrhythmia in the pediatric population, typically considered benign. Nevertheless, more than a few cases evidence its harmful potential, short-term in terms of developing malignant arrhythmia or long-term in terms of developing cardiomyopathy. Gathering more knowledge and experience along with conducting further studies is essential for the enhancement of understanding this condition, and selecting potentially vulnerable patients as well as their treatment.

triglycerides=172 mg/dl) and indications of treatment with Medrol 2 mg/kg with gradual reduction of dosage and Aspirin 4mg/kg.After about 1 month he returns for revaluation, showing good general condition, upward weight curve, biological samples within normal limits.Ultrasound cardiological reassessment and CT angiography further reveal significant aneurysmal dilatation of the left coronary artery. Anticoagulant treatment was completed with enoxaparin.Conclusions KAWASAKI disease associated with COVID 19, may present an unfavorable outcome with lack of response to the initial immunoglobulin treatment and evolution to coronary aneurysm.

Atrioventricular (AV) block is defined as a delay or interruption in the transmission of an impulse from the atria to the ventricles due to an anatomical or functional impairment in the conduction system. The conduction disturbance can be transient or permanent. In third degree AV block, also referred to as complete heart block, there is complete dissociation of the atrial and ventricular activity. Atrioventricular block is considered to be "congenital" when it occurs spontaneously in a fetus or young child. In children, the most common cause of permanent acquired complete AV block is surgery for congenital heart disease. Injury to fetal conduction tissues caused by transplacental exposure to maternal autoantibodies related to systemic lupus erythematosus or Sjogren's syndrome is responsible for 60 to 90 percent of cases of congenital CHB overall1-3. As many as 40 percent of cases of congenital CHB do not present until later in childhood (mean age five to six years). Only rarely do these patients (5 percent) have proven autoimmune etiology. The increased risk of sudden death is associated with the onset of deep bradycardia or ventricular arrhythmia. A routine electrocardiogram is sufficient to diagnose the disease. A 15-year-old girl has been examined at the emergency pediatric outpatient clinic of the University Hospital Centre "Sestre Milosrdnice" for recurrent episodes of presyncope. Physical examination revealed no major deviations other than bradycardia. Her vital signs were within the reference range, with the exception of a pulse of about 44 beats per minute. The electrocardiogram showed atrioventricular dissociation consistent with third degree atrioventricular block. The echocardiogram showed a structurally normal heart except for sinus bradycardia. The girl underwent permanent epicardial pacemaker implantation after which there were no symptoms.Keywords: complete heart block, CHB, complete atrioventricular block, third degree atrioventricular block, congenital atrioventricular block, acquired atrioventrikular block, children, bradycardia Sažetak: AtrioventrikulArni blok srcA trećeg stupnjA u djece Atrioventrikularni (AV) blok je definiran kao kašnjenje ili prekid u prijenosu impulsa iz atrija u ventrikule zbog anatomskih ili funkcionalnih oštećenja u provodnom sustavu srca. Poremećaj provodljivosti može biti prolazan ili trajan. U AV bloku trećeg stupnja, koji se još naziva i kompletni srčani blok, dolazi do potpune disocijacije atrijske i ventrikularne aktivnosti. Atrioventrikularni blok se smatra "kongenitalnim" kada se pojavljuje spontano kod fetusa ili malog djeteta. Stečeni permanentni kompletni AV blok kod djece najčešće je posljedica kirurške korekcije prirođenih srčanih grešaka. Ozljeda fetalnog provodnog srčanog tkiva uzrokovana transplacentarnom izloženošću majčinim autoantitijelama povezanim sa sistemskim eritematoznim lupusom ili Sjogrenovim sindromom odgovorna je za 60 do 90 posto slučajeva kongenitalnog srčanog bloka1-3. Čak 40 posto slučajeva kongenitalnog srčanog bloka se javlja kasnije ...

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Methods During a two year interval, a number of 6 adolescent males were admitted in the ED with severe precordial pain. All were between 14-17 yo. They performed lab investigations, ECG, Echocardiography, Speckle-tracking, Holter ECG and cardiac biomarkers. Two were explored by angiocoronarography due to acute STEMI aspect on ECG, to exclude myocardial infarction. Angio MRI of the heart performed in all patients. Results Six males were admitted for severe precordial pain, 8 on a scale of 0-10, which appeared within the last 12 hours, with a duration of 1-2 hours, accompanied by palpitations. One boy had Duchenne disease and one thrombophilia. The CRP was slightly elevated in all cases, with values between 7 and 56 mg/dl; hsCRP was also elevated. CPK was increased in all cases, varying between 134 -1834 ng/ml. The highest value was in Duchene patient. CPK-MB was slightly increased in 4 patients and very increased in two. Troponin T was positive in two patients with values 54 and 51 pg/ml and increased values in four, between 669 and 2500 pg/ml. Troponin I had very high values, from 501 to 30.000 pg/ml in one case of multifocal myocarditis.NTproBNP was altered in all patients, with values between 72 and 1508 pg/ml. TGO and TGP were elevated, especially TGO. ECG in all cases had the aspect of acute STEMI. Two cases were explored by angiocoronarography with negative result. Ejection fraction was at the lower limit of normal in 3 cases and reduced between 45-49% in the other three. Speckle-tracking was significant in all 6 cases. Holter ECG detected PVC in 2 cases and bradycardia in one.Cardiac MRI revealed inflamed heart muscle at late gadolinium enhancement.MRI was repeated at 6 mo and 1 year after, with good results. Viral serology was negative for: parvovirus, coxackie, adenovirus, cytomegalovirus.Treatment included: AINS, Carvedilol, diuretic, vitamins, bed rest until troponin normalization and sport avoidance 6 mo to 1 year. Conclusions Myocarditis in adolescents almost always mimics myocardial infarction. Cardiac biomarkers help in the diagnosis, evolution and follow-up. Troponin I is more accurate than troponin T. The extremely high values of Troponin I was correlated with severe acute multifocal myocarditis. Cardiac MRI with late gadolinium enhancement is the hallmark of myocarditis.