Cardiac Arrhythmias

The most intimate mechanisms of cardiac arrhythmias are still quite unknown to scientists. Genetic studies on ionic alterations, the electrocardiographic features of cardiac rhythm and an arsenal of diagnostic tests have done more in the last five years than in all the history of cardiology. Similarly, therapy to prevent or cure such diseases is growing rapidly day by day. In this book the reader will be able to see with brighter light some of these intimate mechanisms of production, as well as cutting-edge therapies to date. Genetic studies, electrophysiological and electrocardiographyc features, ion channel alterations, heart diseases still unknown , and even the relationship between the psychic sphere and the heart have been exposed in this book. It deserves to be read

¿CARDIORENAL SYNDROME-ANEMIA¿ COMPLEX IN SMALL ANIMAL MEDICINE: RESEARCH IN DIAGNOSTIC

La sindrome cardiorenale (CRS) pu\uf2 essere definita come un disordine fisiopatologico di cuore e reni in cui la disfunzione acuta o cronica di un organo pu\uf2 indurre una disfunzione acuta o cronica dell'altro. La cardiopatia acquisita pi\uf9 comune che colpisce i cani anziani e che porta a insufficienza cardiaca congestizia (CHF) \ue8 la degenerazione mixomatosa della valvola mitrale (MMVD). Il peggioramento della performance cardiaca e la riduzione della perfusione renale contribuiscono allo sviluppo della malattia renale cronica (CKD) (CRS tipo 2). Nei gatti la pi\uf9 frequente malattia cardiaca \ue8 la cardiomiopatia ipertrofica (HCM), un disturbo miocardico primario caratterizzato da un aumento della massa cardiaca ipertrofia ventricolare sinistra. L'anemia \ue8 spesso associata a insufficienza cardiaca e insufficienza renale in una triade sfavorevole denominata \u201ccomplesso sindrome cardiorenale - anemia". La carenza di ferro pu\uf2 essere presente, da sola o in combinazione con l\u2019anemia, con peggioramento della qualit\ue0 della vita e riduzione della sopravvivenza. Lo scopo della tesi era di descrivere la sindrome cardiorenale nella medicina dei piccoli animali attraverso lo studio delle comorbidit\ue0 e degli strumenti diagnostici innovativi per migliorare la diagnosi rapida e l'approccio medico alle malattie cardiovascolari. In primo luogo, \ue8 stato valutato lo stato di ferro nei cani con MMVD; sebbene non cos\uec frequente come negli esseri umani, la carenza di ferro \ue8 stata riconosciuta in quasi il 20% dei cani con MMVD, con un rischio di 6,3 maggiore di essere incluso in una classe ACVIM pi\uf9 alta per cani con basse concentrazioni di ferro. La dimetilarginina simmetrica, un nuovo biomarker di velocit\ue0 di filtrazione glomerulare, \ue8 stata valutata su sieri di cani con MMVD e si \ue8 dimostrata non influenzata dalla presenza della malattia cardiaca, potendo quindi essere considerata un biomarker di funzionalit\ue0 renale affidabile in questi cani. La creatin-chinasi \ue8 stata misurata in sieri di gatti sani e gatti con diverse forme di cardiomiopatia per evidenziare il suo eventuale ruolo nella diagnosi precoce della malattia; i risultati suggeriscono che la macro-CK1 felina pu\uf2 avere una struttura diversa rispetto a quella di altre specie e che, fra le frazioni espresse, CK-MB potrebbe avere un ruolo nella diagnosi delle cardiomiopatie feline. La precisione e l'affidabilit\ue0 di D-Heart, il primo elettrocardiografo portatile a pi\uf9 derivate utilizzabile nel paziente canino, sono state valutate, per la diagnosi rapida delle aritmie. Il dispositivo ha dimostrato una registrazione efficace e accurata dell'ECG nei cani inclusi nello studio. Infine, il kit ELISA selezionato per rilevare l'aldosterone su campioni di urina di cane \ue8 risultato essere accurato ed efficace, costituendo un'alternativa semplice, sicura ed economica al metodo RIA. Il confronto tra cani sani e cani con MMVD (B1) non ha mostrato differenze statisticamente significative nel rapporto aldosterone urinario:creatinina (UAldo:C). I valori medi del rapporto UAldo: C nel presente studio erano maggiori di quelli riportati in letteratura, suggerendo la necessit\ue0 di uno studio approfondito per rivalutare la soglia di normalit\ue0 stabilita dalla letteratura (1.0 \u3bcg/g), che non sembra essere valida nella popolazione del presente studio.Cardiorenal syndrome (CRS) can be defined as a pathophysiologic disorder of the heart and kidneys whereby acute or chronic dysfunction of one organ may induce acute or chronic dysfunction of the other. The most common acquired heart disease affecting old dogs and leading to congestive heart failure (CHF) is myxomatous mitral valve disease (MMVD). The worsening of cardiac performances and reduction of renal perfusion contribute to the development of chronic kidney disease (CKD) (CRS type 2). In cats the most common cardiac disease is hypertrophic cardiomyopathy (HCM), a primary myocardial disorder characterized by increased cardiac mass and a hypertrophied, not dilated, left ventricle. Anemia is often associated with heart failure and renal insufficiency in an unfavorable triad called \u201cCRS-anemia\u201d complex. Iron deficiency can be present, alone or in combination with anemia, worsening quality of life and shortening survival. The aim of the thesis was to describe cardiorenal syndrome in small animal medicine trough the identification of general comorbidities and particular novel diagnostics tools to improve fast diagnosis and the medical approach to the cardiovascular diseases in small animal medicine. Firstly, iron status in dogs with MMVD was evaluated; although not as frequent as in humans, iron deficiency was recognized in almost the 20% of dogs with MMVD, with a 6.3 higher risk of being included in a higher ACVIM class. Symmetric dimethylarginine, a novel biomarker of glomerular filtration rate, was evaluated on sera of dogs with MMVD and proved to be not influenced by the presence of the heart condition and can thus be considered a reliable biomarker in these dogs. Creatine-kinase was measured in sera of healthy cats and cats with different forms of cardiomyopathy to highlight its role in the early diagnosis of the disease; the results suggests that feline macro-CK1 may have a different structure compared with other species and a potential role of CK-MB in the evaluation of feline cardiomyopathies. Accuracy and reliability of D-Heart, the first portable, multiple lead smartphone electrocardiograph in the canine patient, was evaluated, for rapid diagnosis of arrhythmias. The device proved effective and accurate recording of ECG in the canine patient. Finally, the selected ELISA kit to detect aldosterone in canine urine was found to be accurate and effective, constituting a simple, safe and economical alternative to the radioimmunoassay method. Comparison between healthy dogs and dogs with MMVD (B1) showed no statistically significant difference in urinary aldosterone:creatinine (UAldo:C) ratio. The mean values of UAldo:C ratio in the present study were greater than those reported in literature, suggesting the need of a deep study to re-evaluate the normality threshold set by the literature (1.0 \u3bcg/g), which does not seem to be valid in the population of the present study

Pacing the heart:one site fits all?

In a healthy heart, contraction/pumping is controlled by an electrical stimulus. This ensures that the heart contracts synchronously. When a problem arises with generating or conducting this electrical stimulus, people are fitted with a pacemaker. Our research shows that - in contrast to current technology - stimulating the ventricular septum is safer and better for the pump function. Stimulation of the ventricular septum can prevent (symptoms of) heart failure. Survival also improves

Caractérisation et traitement du substrat électrique pour la thérapie de resynchronisation cardiaque

We aimed to characterize the electrical substrate amenable to biventricular pacing (BVP) and to assess the actual value of electrical resynchronization. We showed, both with respect to surface ECG and detailed ventricular electrocardiographic mapping (ECM), a strong relationship between the baseline electrical dyssnchrony and the hemodynamic response to BIV pacing. Compared with standard ECG, ECM allows a more detailed analysis of the ventricular dyssynchrony and better predicts clinical outcomes after BVP. A minimal amount of electrical dyssynchrony, in particular a sufficient LV activation delay relative to right ventricular activation, is a prerequisite to the hemodynamic response to BVP. Due to their advanced electrical dyssynchrony, patients with left bundle branch block present potential for BVP positive response which acts by electrical resynchronization. Conversely, BVP worsens the electrical activation (iatrogenic dyssynchrony) and hemodynamics in patients with narrow QRS suffering from insufficient electrical dyssynchrony at baseline. Patients with unspecified conduction disorders show variable levels of electrical dyssynchrony and as a consequence mixed results to BVP. Similarly, ECM reveals a variable degree of left ventricular activation delay in patients chronically paced in the right ventricle. Beside the electrical resynchronization, other mechanisms are involved in the cardiac pump function improvement such as the redistribution of the mechanical work over the right and left ventricles. Through ventricular interaction, the RV myocardium importantly contributes to the improvement in LV pump function induced by single site LV pacing.L'objectif de ce travail était de mieux appréhender les mécanismes impliqués dans la réponse à la resynchronisation biventriculaire (BIV) en insistant sur la caractérisation du substrat électrique éligible à la thérapie et l'intérêt de la resynchronisation électrique. Nous avons démontré qu'il existe une relation forte entre l'asynchronisme électrique de base défini tant par l'ECG de surface que par cartographie détaillée de l'activation ventriculaire (ECM) et la réponse hémodynamique à la stimulation BIV. Par rapport à l'ECG de surface, l'ECM permet une caractérisation plus fine de l'asynchronisme électrique ventriculaire avec une meilleure prédiction de la réponse clinique à la stimulation BIV. La présence d'un asynchronisme de base minimum, en particulier d'un retard d'activation ventriculaire gauche (VG) par rapport au ventricule droit (typiquement >SOms), est un prérequis à l'efficacité de la thérapie. Les patients avec bloc de branche gauche présentent un haut degré d'asynchronisme et la stimulation BIV agit sur ce substrat par resynchronisation de l'activation électrique. A contrario, la stimulation BIV dégrade la séquence d'activation ainsi que l'hémodynamique des patients à QRS fins (dyssynchronie iatrogène). Les patients présentant un trouble de conduction aspécifique présentent des degrés variables d'asynchronie électrique et en conséquence des réponses contrastées à la stimulation BIV. De même, l'analyse ECM de l'asynchronisme des patients chroniquement stimulés sur le ventricule droit a permis de mettre en évidence des degrés variables de retard d'activation du VG. Si la resynchronisation électrique est garante d'une amélioration de la fonction cardiaque, d'autres mécanismes sont impliqués telle la redistribution du travail segmentaire au sein du myocarde ventriculaire. L'efficacité de la stimulation mono-VG implique une participation accrue du ventricule droit au travail global (interaction ventriculaire)

Cardiovascular magnetic resonance of the right ventricle

Introduction: Whilst most of the attention has been devoted to the left ventricle in cardiovascular disease, the right ventricle has been somewhat neglected. In the last decades, there has been a renewal of interest in the right ventricle, in part driven by advances in cardiovascular imaging. Methods: Cardiovascular magnetic resonance is arguably the best imaging modality for the study of the right ventricle. In this research thesis, cardiovascular magnetic resonance was used as the primary research tool to assess the right ventricle in different conditions and settings. Results: This thesis encompasses five studies that have been published as peer - reviewed articles. The results of these studies were the following: 1)Right ventricular dilatation and dysfunction was found in a group of patients with Marfan syndrome, further supporting the existence of a Marfan - related cardiomyopathy; 2) In thalassaemia major, right ventricular volumes and ejection fraction differed from healthy controls, and new reference ranges based on patients without iron overload were derived; 3) Myocardial iron loading in thalassaemia major was associated with progressive right ventricular dysfunction; 4) Right ventricular dysfunction due to myocardial siderosis was reversible with effective iron chelation therapy, and; 5) In advanced heart failure, right ventricular function was a predictor of response and outcomes in patients undergoing cardiac resynchronization therapy. Conclusion: The right ventricle is an essential component of the circulatory system, and should be more widely evaluated in patients with cardiopulmonary disease