Propranolol, a first-generation nonselective β-adrenoceptor blocking agent, is commonly used to treat pediatric arrhythmias. Atenolol, relatively long-acting, cardioselective β-adrenoceptor blocking agent, has been successfully used in adults with supraventricular tachycardia (SVT). There is only one report on the use of atenolol in children with SVT, and our report is on the first long-term prospective study to evaluate the use of atenolol in children. A group of 22 children <18 years of age with clinical SVT were enrolled in the study. The tachycardia was documented on electrocardiograms in each case and was confirmed by electrophysiologic studies in some. Once- a-day oral atenolol was started as a monotherapy. Of the 22 children with various types of SVT, 13 (59%) were well controlled on long-term oral atenolol therapy. The effective dose of atenolol ranged between 0.3 and 1.3 mg/kg/day (median effective dose 0.7 mg/kg/day). Five children had some adverse effects. However, none in the successful group of 13 patients required drug discontinuation because of such effects. Once-a-day oral atenolol as a monotherapy is effective and relatively safe for long-term management of SVT during childhood. It is an attractive alternative β- adrenoceptor blocking agent for the management of pediatric arrhythmias.

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Šiame darbe apžvelgiama Vilniaus Universiteto Širdies ligų ir kraujagyslių klinikoje 1991−2008 metais sukaupta patirtis taikant nemedikamentinį gydymą pacientams su supraventrikulinėmis tachikardijomis ir skilveliniais ritmo sutrikimais. Apibendrinome nemedikamentinio gydymo rezultatus 1693 pacientams: 753 pacientams su atrioventrikulinio mazgo paroksizmine tachikardija, 657 pacientams su papildomais laidumo takais, 169 pacientams su skilvelinėmis tachikardijomis. Be to, apibendrinome kardioverterių defibriliatorių implantavimo rezultatus 118 pacientų. Nustatėme, kad atrioventrikulinio mazgo tachikardijos kateterinės abliacijos efektyvumas 99,2%, komplikacijų dažnis 0,53%. Įrodėme, kad saugu atlikti „lėtos“ zonos abliaciją pacientams su ilgu PQ intervalu. Papildomų laidumo takų kateterinė abliacija buvo efektyvi 98,1% atvejų, komplikacijų dažnis 1,7%. Papildomų laidumo takų grupėje sudėtingiausios lokalizacijos yra užpakalinė pertvarinė dalis ir vidurinė pertvarinė dalis (pastaroji – dėl rizikos sukelti III laipsnio AV blokadą). Skilvelinių tachikardijų kateterinės abliacijos rezultatas priklauso nuo etiologijos. „Idiopatinių“ skilvelinių tachikardijų atvejais kateterinės abliacijos efektyvumas viršija 90%. Koronarinės širdies ligos ir kardiomiopatijų atvejais kateterinė abliacija mažiau efektyvi (~60%). Kardioverterių defibriliatorių grupėje iki 11 m. stebint pacientus, defibriliatorius suveikė 68,6% atvejų. / This paper reviews the 1991−2008 experience with non-pharmacological treatment of supraventricular and ventricular tachycardias in the Clinic of Heart and vessel diseases of Vilnius University. We summarized the results of managing 1693 patients: 753 patients with atrioventricular nodal tachycardia, 657 patients with accessory pathways, 169 patients with ventricular tachycardias, and 118 patients with implanted cardioverter defibrillators. We have shown that the success rate of catheter ablation for atrioventricular nodal tachycardia is 99.2% with complication rate 0.53%. The safety of ablating the “slow” pathway in patients with prolonged PQ interval has been shown. The success rate of catheter ablation of accessory pathways is 98.1% with 1.7% complication rate. The most complex accessory pathway localization for ablation was posteroseptal area and midseptal area (the latter because of the risk to induce a complete atrioventricular block). The result of catheter ablation for ventricular tachycardia depends on etiology. For “idiopathic” ventricular tachycardias success rate exceeds 90%. In patients with coronary heart disease and cardiomyopathies, catheter ablation is less effective (60%). During the follow-up with duration up to 11 years, 68.6% of patients with implanted cardioverter defibrillators have experienced therapy delivered by the device.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2009. / Härtill 4 uppsatser.

Bradyarrhythmias are common clinical findings consisting of physiologic and pathologic conditions (sinus node dysfunction and atrioventricular [AV] conduction disturbances). Bradyarrhythmias can be benign, requiring no treatment; however, acute unstable bradycardia can lead to cardiac arrest. In patients with confirmed or suspected bradycardia, a thorough history and physical examination should include possible causes of sinoatrial node dysfunction or AV block. Management of bradycardia is based on the severity of symptoms, the underlying causes, presence of potentially reversible causes, presence of adverse signs, and risk of progression to asystole. Pharmacologic therapy and/or pacing are used to manage unstable or symptomatic bradyarrhythmias.

Introdução: A morte súbita é a principal causa de morte na doença de Chagas, correspondendo de 55 a 65% dos casos. Observa-se que parte destas, ocorre em pacientes com função ventricular esquerda (FEVE) preservada, levando a acreditar que fatores desestabilizadores do substrato arritmogênico exercem um importante papel nestes eventos. Evidências já demonstraram a depressão parassimpática como fator contribuinte na gênese de arritmias diversas em presença de cardiopatia isquêmica. Assim, insiste-se na necessidade de se identificar precocemente quais os pacientes, no contexto da cardiopatia chagásica crônica, apresentam risco aumentado para o desenvolvimento de eventos arrítmicos complexos. Acredita-se que a avaliação autonômica identifique subgrupos distintos de risco. O presente estudo teve como objetivo determinar a sensibilidade do barorreflexo (SBR) em pacientes com doença de Chagas, nas formas indeterminada (GI) e arritmogênica com taquicardia ventricular não sustentada (GII) e com taquicardia ventricular sustentada (GIII) e, secundariamente, avaliar a associação entre a severidade da arritmia ventricular com o grau de comprometimento da SBR. Métodos: 42 pacientes foram submetidos à monitorização cardiovascular não invasiva pelo sistema Task Force ® onde foi determinada a SBR, utilizando o método da fenilefrina e analisada a variabilidade da frequência cardíaca (VFC) no domínio do tempo por meio da eletrocardiografia dinâmica de 24horas e a FEVE, por meio da ecocardiografia. Resultados: Observou-se diferença estatística significativa entre os grupos em relação à SBR em resposta à fenilefrina. O GIII apresentou o menor valor de SBR (6,09 ms/mmHg) quando comparado aos GII (11,84ms/mmHg) e GI (15,23ms/mmHg). Após comparação múltipla entre os grupos, verificou-se diferença significativa entre GI e GIII (p= 0,01). Quando se correlacionou SBR e densidade de extra-sístoles ventriculares (EV), observou-se que todos os pacientes portadores de baixa densidade de EV (< 10/hora) apresentavam SBR preservada (6,1ms/mmHg).Em contrapartida, entre aqueles com alta densidade de EV (>10/hora) somente 59% tinham SBR preservada (p=0,003). Nos pacientes com SBR deprimida (3,0-6,0 ms/mmHg) houve maior densidade de EV (p=0,01). Pacientes com SBR preservada apresentaram tanto função ventricular normal como moderadamente comprometida (66,7% com FEVE<40% e 79,5% com FEVE40%; p=0,62). O mesmo observou-se em pacientes com SBR moderadamente deprimida, (15,4% com FEVE<40% e 33,3% com FEVE40%; p=0,46). Não foi verificada correlação entre SBR e VFC. Ao se aplicar o modelo de regressão logística, observou-se que somente a SBR influenciou o aparecimento da taquicardia ventricular sustentada (p=0.028). Conclusão: A SBR está preservada na forma indeterminada da doença de Chagas e diminuída na forma arritmogênica. O comprometimento da SBR é progressivo e acompanha a evolução da doença, sendo mais intenso nos pacientes com arritmias ventriculares mais complexas. O grau de disfunção autonômica não se correlacionou com a função ventricular, mas, sim, com a densidade e a complexidade das arritmias / Introduction: Sudden death is the main cause of death in Chagas disease, corresponding to 55 to 65% of the cases. Some of these occur in patients with normal or almost normal left ventricular function (LVF), leading us to believe that factors that destabilize the arrhythmogenic substrate play an important role in these events. Evidences show parasympathetic depression to be a contributing factor in the genesis of diverse arrhythmias in the presence of ischemic heart disease. Thus, we insist on the need of an early identification of the patients, in the context of chronic Chagas heart disease, that are at increased risk of developing complex arrhythmic events. It is possible that autonomic assessment allows the identification of distinct risk subgroups. The objective of this study was to determine the baroreflex sensitivity (BRS) in patients with the indeterminate form of Chagas disease, (GI), and with the arrhythmogenic form of Chagas disease with nonsustained ventricular tachycardia (GII) and sustained ventricular tachycardia (GIII) and to assess the correlation between the severity of ventricular arrhythmia and the degree of BRS impairment. Methods: Forty-two patients were subjected to noninvasive cardiovascular monitoring using the Task Force® system. The phenylephrine method was used to determine BRS, 24- hour dynamic electrocardiography was used to analyze heart rate variability (HRV) over time and echocardiography was used to determine LVF. Results: A statistical difference was observed between the groups regarding their BRS to phenylephrine. GIII presented the lowest BRS value (6.09 ms/mmHg) when compared with GII (11.84ms/mmHg) and GI (15.23ms/mmHg). After multiple comparisons among the groups, a significant difference was found between GI and GIII (p=0.01). When BRS was correlated with ventricular extrasystole (VE) density, all patients who had low VE density (<10/hour) had preserved BRS (6.1ms/mmHg). On the other hand, only 59% of those with high EV density (>10/hour) had preserved BRS (p=0.003). In patients with moderately depressed BRS (3.0-6.0 ms/mmHg) there was a greater density of EV (p=0.01). Patients with preserved BRS had preserved or moderately compromised LVF (66.7% with LVF<40% and 79.5% with LVF40%; p=0.62) as had patients with moderately depressed BRS (15.4% with LVF<40% and 33.3% with LVF40%; p=0.46). There was no correlation between BRS and LVF. When the logistic regression model was applied, only BRS influenced the presence of sustained ventricular tachycardia (p=0.028). Conclusion: BRS is preserved in indeterminate Chagas disease and diminished in the arrhythmogenic form. The BRS impairment is progressive as the disease progresses, being more evident in patients with more complex ventricular arrhythmias. The degree of autonomic dysfunction did not correlate with ventricular function but with the density and complexity of the arrhythmias

Cardiovascular disease (CVD) claims more lives than any other disease in the world. Although numerous biological pathways share the blame, ventricular tachyarrhythmia (VT) is estimated to account for ~25% of all CVD deaths. A complete understanding of the molecular mechanisms underlying VT is unknown but recent studies have linked VT to improper calcium handling in the heart (canine). The principle calcium regulator in the muscle cell is the calcium ion release channel (aka RyR). Numerous endogenous and exogenous compounds can affect the way the RyR regulates calcium. In particular, abnormal levels of oxidants (reactive oxygen species) can oxidize critical thiol groups on the RyR and modulate its activity. Interestingly, high levels of oxidants are also associated with numerous bodily disease states including cancers, muscle fatigue/failure, and CVD. In this thesis, two important dietary antioxidant compounds, the anthocyanidins pelargonidin and delphinidin, are evaluated for their effects on regulating the transport of calcium through the calcium release channel (RyR1) of the sarcoplasmic reticulum of skeletal muscle. Pelargonidin and delphinidin are structurally similar with delphinidin only differing from pelargonidin by the addition of two hydroxyl groups. Both compounds undergo time dependent structural changes in aqueous solutions at physiological pH and a mixture of more than four structures of each compound can be present in solution simultaneously. Pelargonidin and delphinidin show distinct differences in their calcium flux regulating effect on the RyR1. Delphinidin stimulates calcium flux and RyR1 activity where as pelargonidin can cause both inhibition and stimulation of the RyR1. The strength of stimulation and inhibition of calcium transport through the RyR by delphinidin and pelargonidin may be attributed to the structural and chemical changes in those compounds that occur in solutions near physiological pH and the subsequent chemical characteristics of the diverse set of structures that are simultaneously present in solution.

Supraventrikulinės grįžtamojo ryšio tachikardijos vaikams yra gana dažnas širdies ritmo sutrikimas, kurį sąlygoja papildomi laidumo pluoštai (Kento, Mahaimo), atrioventrikulinės jungties dviejų takų – lėtojo ir greitojo -fiziologiniai ypatumai. Iki gydymo radiodažnine (RD) energija eros, kurios pradžia – 1980 - tieji metai (vaikų amžiuje – 1990 - tieji metai), tachiaritmijų gydymas kėlė daug problemų (ne visuomet efektyvus medikamentinis gydymas, „atviros” širdies operacijos). Mūsų klinikoje pirmoji radiodažninė abliacija (RDA) vaikui atlikta 1991 metais. Pastaruoju metu dėl grįžtamojo ryšio supraventrikulinių tachikardijų (SVT) Kauno klinikose vaikams per metus atliekama apie 20 – 30 tokių procedūrų. Šio gydymo metodo efektyvumas bei mažas komplikacijų skaičius lėmė, kad gydymas RDA tapo pasirinktinu gydymo metodu, gydant SVT. Sukaupta nemažai duomenų apie ankstyvojo ir vėlyvesniojo laikotarpio (praėjus po RDA operacijos 1-29 mėn.) pacientų išgyvenamumą, komplikacijas, širdies ritmo variabilumo pokyčius, kai kuriuos širdies morfometrijos ir funkcijos rodiklius: vožtuvų būklę, įprastinius sistolinę ir diastolinę funkciją atspindinčius rodiklius. Tačiau nėra žinoma apie širdies laidžiosios sistemos, širdies ritmo, ritmo variabilumo pokyčius vėlyvuoju laikotarpiu (praėjus po gydymo RDA daugiau nei dvejiems metams). Pagal šiuos duomenis, retrospektyviai, t.y. jau pagydžius pacientą, galima spręsti apie širdies laidžiosios sistemos ypatumus. Šios žinios reikalingos tiek vaiko... [toliau žr. visą tekstą] / The supraventricular tachycardias (SVT) (atrioventricular reentrant tachycardia due to accessory pathways, atrioventricular nodal reentrant tachycardia) are common in children. It is the most common arrhythmia in Wolff –Parkinson White syndrome. The electrophysiologic – morphologic substrates responsible for both AV node reentrant tachycardia (AVNRT) and AV reentrant tachycardia are thought to be present from birth. Radiofrequency ablation (RFA) successfully eliminates the extra pathway by the application of thermal energy typically leaving only normal conduction. The radiofrequency treatment era started in 1980 (and in 1990 for pediatric patients); the treatment of tachyarrhythmia was problematic until then because drug treatment or open heart surgery were not successful rather frequently. At our clinic, the first RFA for a child was performed in 1991. Nowadays, approximately 20 – 30 RFA procedures per year for children suffering from various types of supraventricular tachycardia are performed in our clinic. This method of treatment is effective and the number of complications is low; therefore, it became a method of choice to treat SVT. Data concerning long-term and short-term survival (1 – 29 months after RFA procedure), complications, changes of heart rhythm variability, certain heart morphometry and functional parameters (including valves function, routine indices of systolic and diastolic function) is rather common. However, alternations of heart conductive system... [to full text]

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.