Dissertations / Theses on the topic 'Cardiology. Electrocardiography'

The standard first aid for a heart attack resulting in cardiopulmonary arrest is effective cardiopulmonary resuscitation (CPR). Chest compressions are most commonly performed on a flat surface with the rescuer kneeling next to the victim with one hand on top of the other on the sternum and elbows straight. This technique of being on the ground may be challenging for those without the mobility and strength to get up and down from the ground. In 2005, the American Heart Association (AHA) Guidelines listed “pedal”, or heel, compression as an acceptable alternative to standard chest compressions (Trenkamp & Perez, 2015). That same year, the recommended depth of a compression increased from 3.8 cm to 5.0 cm (Trenkamp & Perez, 2015). To attain such a depth, extra force and strength arerequired. The heel method may be especially reasonable for those rescuers who cannot attain the floor and those who do not have the cardiovascular or muscular strength to perform traditional chest compressions. The purpose of this study was to evaluate the effects of performance of hands only (HO) versus the combination (CO) of hands only plus pedal CPR on the electrocardiogram, including heart rate and heart rhythm. The subjects utilized in this investigation were six men and nine women between 56 and 71 years of age from San Luis Obispo County in California. Subjects underwent two trials with at least a 15 hour rest period in between but no more than one week. Subjects were randomly assigned to either the Combination (CO) trial or the Hands Only (HO) trial. When they came back for their second trial, they did the trial that they did not do the first time. On average, participants were able to sustain the combination of HO plus pedal CPR longer (9.47 minutes) than they were able to perform standard HO CPR (9.02 minutes) but this difference was not statistically significant (p=0.16). Mean maximum heart rate was 133 ± 23.7 bpm during the CO trial and 125.4 ± 21.9 bpm during the HO trial (p=0.12). Mean percentage of the HR reserve was 75.1% during the CO trial and 61.1% during the HO trial (p=0.09). Mean RPE was not significantly different between CO and HO trials (p=0.2124), nor between genders (p=0.42090). However, for both trials combined the mean RPE was significantly greater at 5 minutes of CPR (4.45 ± 0.53) than at 2 minutes of CPR (3.38 ± 0.31), (p It may take time for individuals to accept pedal CPR as a viable resuscitation method. With the majority of sudden cardiac arrests occurring in the home among older adults in society, it is important to recognize that pedal CPR is an acceptable method and that a rescuer may have this choice if they either need a break from standard CPR or if they can not attain the ground.

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Tachycardia-induced cardiomyopathy (TIC) is a reversible cause of LV systolic dysfunction that can complicate any supraventricular or ventricular tachyarrhythmia. This study is the first to compare features of pure and impure TIC. We found that impure TIC may develop more quickly than pure TIC, as impure TIC patients have a shorter duration and more severe symptoms at presentation, which suggests that underlying structural heart disease is a risk factor in the pathogenesis of TIC.

Luis Calandre Ibáñez (Cartagena 23/3/1890-Madrid 29/9/1961), estudió Medicina en Madrid, siendo discípulo de Cajal, Achúcarro y Madinaveitia en Madrid y de Nicolai y Benda en Alemania. Realizó estudios de Histología sobre la esructura de la fibra cardiaca, para comprender mejor la fisiopatología del corazón, campo de su especial dedicación, siendo uno de los introductores de la electrocardiografía en España, estudiando especialmente los trastornos del ritmo basándose en ella.Fundó y dirigió el Laboratorio de Anatomía Microscópica de la Residencia de Estudiantes (1914-1931). Fue Jefe del Servicio de Cardiología del Hospital Central de la Cruz Roja y Director del Hospital de Carabineros durante la guerra civil (1937.1939). Publicó más de setenta artículos en revistas especializadas y ocho libros de contenido científico. Fundó y dirigió la revista "Archivos de Cardiología y Hematología" (1920-1936). Desarrolló una intensa labor social, política y cultural y al finalizar la guerra civil fue procesado y condenado padeciendo el exilio interior y el olvido científico.
Luis Calandre Ibáñez (Cartagena 1890-Madrid 1961), studied medicine in Madrid, where he was a disciple of Cajal, Achúcarro and Madinaveitia and then of Nicolai and Benda in Germany. He specialised in cardiac physiopathology, and studied histology on the struc Civil war. He published more than seventy articles in specialist journals and eightscientificbooks. He founded and directed the journal "Archivos de Cardiología y Hematología" (1920-1936). Intensely involved in social, political and cultural activities, he was tried and sentenced at the

Background: Atrial fibrillation (AF) confers high risk of stroke, but often goes undiagnosed due to difficulties in its diagnosis. AF detection is important in post-stroke populations for secondary prevention and smartwatches have emerged as a promising modality for detecting AF, but little is known about their use in older adults who have experienced a stroke. Methods: This dissertation uses data from the Pulsewatch study, a two-phased trial assessing accuracy, usability, and adherence of smartwatch-based AF detection among older patients after stroke. Analyses performed include: descriptive statistics, linear and logistic regressions, qualitative and mixed-methods analyses, mixed effects modeling, and group-based trajectory modeling. Results: The Pulsewatch system was 91% accurate in detecting AF compared to a clinical gold-standard. Participants found the system easy to use, but indicated that streamlining the smartwatch’s functionalities to focus on passive cardiac monitoring is crucial. Improving battery life to allow for longer wear time would alleviate anxiety in some participants. Participants with previous experience using cardiac rhythm monitors rated the system lower on usability, but overwhelmingly preferred it to previous monitors due to the watch’s comfort, appearance, and convenience. Watch wear decreased over time, and we observed three distinct patterns of decline. No individual-level characteristics were associated with usability or adherence to watch wear. Conclusions: Smartwatches are promising for AF detection in older adults after stroke, though while they offer high accuracy and usability, adherence to wear is low. Strategies to encourage extended watch wear are necessary to realize the potential of smartwatches as a viable cardiac monitoring modality.

Dissertação de Mestrado Integrado em Medicina Veterinária
Nos anos 40 do século passado, Norman Holter descobriu a electrocardiografia ambulatória. Em alguns anos o monitor Holter chegou à Medicina Veterinária, sendo actualmente um meio de diagnóstico prático, não doloroso, não invasivo e bem tolerado, que permite a monitorização do funcionamento cardíaco por 24 horas e portanto a identificação e quantificação das arritmias presentes num traçado com tal duração. Até à data e no que diz respeito aos cães não se conhece o número exacto de arritmias considerado fisiológico. Vários têm sido os trabalhos efectuados em animais com cardiomiopatia dilatada idiopática e estenose subaórtica congénita, sabendo-se no primeiro caso que os animais que a apresentam têm elevada incidência de arritmias ventriculares. No segundo ainda se investiga a presença de arritmias ventriculares e alterações do segmento ST tentando estabelecer uma relação entre as mesmas e a probabilidade de síncope ou morte súbita. O Holter tem-se mostrado, também, uma ferramenta fundamental na explicação de síncopes arritmogénicas e na monitorização de terapêuticas antiarrítmicas. Os modernos Holter identificam automaticamente complexos ectópicos e respectivas taquicardias, sendo que a identificação de outras arritmias depende da análise cuidada do traçado por um técnico competente. Na monitorização de 9 canídeos com lesão degenerativa crónica da valva mitral detectaramse, principalmente, arritmias supraventriculares e apesar de não se ter estabelecido uma relação entre o aumento atrial e a frequência de complexos supraventriculares prematuros por hora, verificou-se que a complexidade de tais arritmias aumenta tendencialmente com a progressão da doença. Estudos futuros comprovarão se estas se tratam de conclusões meramente descritivas ou não.
ABSTRACT - The Ambulatory Electrocardiographic Monitorization in Canine Cardiology: Clinical Study of Nine Dogs with Chronic Degenerative Mitral Valve Disease -- In the 1940´s, Norman Holter discovered ambulatory electrocardiography. In a few years Holter monitoring reached veterinary medicine and today it is a practical, non painful, non invasive and well tolerated diagnostic tool that allows cardiac monitorization for 24 hours and therefore the detection and quantification of cardiac arrhythmias. The exact number of physiologic arrhythmias in dogs remains unknown. There are several published studies on idiopathic dilated cardiomyopathy and congenital aortic stenosis. In the first case animals present ventricular arrhythmias while in the second studies still focus on monitoring the presence of ventricular arrhythmias and ST segment modifications and try to establish some relation between these factors and syncope or sudden death. Holter monitoring is also essential to explain arrhythmogenic syncope and to access antiarrythmic therapy efficacy. The modern Holter softwares are able to identify ectopic complexes and ectopic tachycardias but the identification of others arrhythmias depends on the technician´s analysis. When monitoring 9 dogs with mitral disease, supraventricular arrhythmias were the most significant finding. Although no relation was established between atrial enlargement and the hourly frequency of supraventricular premature complexes, it was found that those arrhythmias were more complex with the progression of the disease. Future studies are required in order to decide if these findings are merely descriptive or not.

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The obesity is a morbid condition commonnly incident in veterinary practice, generally associate to the companion animals reduction of time and quality of life. This factor, added to the regularity that it is observed, makes from obesity, nowadays, the most important metabolism disease in dogs, being still able to promote serious health problems, including cardiovascular disorders. For this study, 14 medium-sized neutered mongrel adult female dogs were divided in two groups and submitted to a program of weight gain. Group I, presenting highest percentage of weight gain (average 21.4% above the initial weight, in average) and Group II, with shortest weight gain percentage (15% above the initial weight, in average). Afterwards, both groups were submitted to a obesity correction food program, to reach the initial weight. During the food programs, in the initial phase (T1), obesity phase (T2) and final phase of weight reduction (T3), examinations carried out were: electrocardiographic, radiographic and mensurations of the blood pressure. During the phases T2 and T3, ecodopplercardiographic examinations of all dogs were also performed. At the end of the experimental phase, every variables obtained were statistically evaluated, comparing the groups and the different phases within the same group. The results revealed no significant eletrocardiographic and ecodopplercardiographic alterations, considering up to 21% of increment on body weight; increase of cardiac silhouette on radiographic evaluation during the obesity phase and decrease after the weight loss, and increase of arterial systolic pressure after the weight increment.
A obesidade é uma condição mórbida de ocorrência comum na prática veterinária, estando geralmente associada à redução do tempo e da qualidade de vida dos animais de companhia. Esse fator, unido à regularidade com que é observada, faz da obesidade, atualmente, a forma mais importante de doença do metabolismo em cães, podendo provocar sérios problemas de saúde, dentre eles os distúrbios cardiovasculares. Neste trabalho, 14 cadelas de porte médio, sem raça definida, adultas e castradas foram divididas em dois grupos e submetidas a um programa de ganho de peso. O Grupo I com maior porcentagem de ganho de peso (em média 21,4% acima do peso inicial) e o Grupo II com menor porcentagem de ganho de peso (em média 15% acima do peso inicial). Posteriormente foram submetidas a um programa alimentar de correção da obesidade até atingirem o peso inicial. Durante os programas alimentares, na fase inicial (T1), fase de obesidade (T2) e fase final de redução de peso (T3) foram realizados exames eletrocardiográficos, radiográficos e mensurações da pressão arterial e nas fases T2 e T3 exames ecodopplercardiográficos em todas as cadelas. Ao final da fase experimental, todas as variáveis obtidas foram avaliadas estatisticamente, comparando os grupos e as diferentes fases dentro do mesmo grupo. Os resultados revelaram que não ocorreram alterações eletrocardiográficas e nem ecodopplercardiograficas significativas, considerando incremento de peso corporal de até 21%; aumento significativo da silhueta cardíaca à avaliação radiográfica, na fase de obesidade, e diminuição da mesma após perda de peso e a pressão arterial sistólica dos cães aumenta com o incremento do peso.

Les tachycardies ventriculaires (TV) et atriales (TA) sont les arythmies les plus fréquemment diagnostiquées en clinique. En vue d’ablater les tissus pathologiques, deux techniques de diagnostic sont utilisées : la cartographie électro-anatomique pour un diagnostic précis à l’aide d’électrogrammes (EGM) mesurés par cathéters intracardiaques et repérés sur la géométrie tridimensionnelle (3-D) de la cavité étudiée ; et l’imagerie électrocardiographique non-invasive (ECGi) pour une vision globale de l’arythmie, avec des EGM reconstruits mathématiquement à partir des électrocardiogrammes et des géométries cardio-thoraciques 3-D obtenues par CT-Scan. Les TV et TA sont alors diagnostiquées en étudiant les cartes d’activation qui sont des représentations des temps de passage locaux de l’onde d’activation sur la géométrie 3-D cardiaque. Cependant, les zones de ralentissement favorisant les TV et TA, et leurs motifs de propagation spécifiques n’y sont pas facilement identifiables. Ainsi, la caractérisation locale de la propagation de l’onde d’activation peut être utile pour améliorer le diagnostic. L’objet de cette thèse est le développement d’une méthode de caractérisation locale de la propagation de l’onde d’activation. Pour cela, un champ vectoriel de vitesse est estimé et analysé. La méthode a en premier lieu été validée sur des données simulées issues de modélisation, puis appliquée 1) à des données cliniques issues de l’ECGi pour la localisation des cicatrices d’infarctus et pour améliorer le diagnostic des TA; et 2) sur des données obtenues par cartographie électro-anatomique pour caractériser les zones pathogènes
Ventricular (VT) and atrial (AT) tachycardias are some of the most common clinical cardiac arrhythmias. For ablation of tachycardia substrates, two clinical diagnosis methods are used : electro-anatomical mapping for an accurate diagnosis using electrograms (EGMs) acquired with intracardiac catheters and localized on the three-dimensional (3-D) mesh of the studied cavities ; and non-invasive electrocardiographic imaging (ECGi) for a global view of the arrhythmia, with EGMs mathematically reconstructed from body surface electrocardiograms and the 3-D cardio-thoracic meshes obtained with CT-scan. VT and AT are diagnosed studying activation time maps ; that are 3-D representations of the transit time of the activation wavefront on the cardiac mesh. Nevertheless, slow conduction areas, a well-known pro-arrhythmic feature for tachycardias, and the tachycardias specific propagation patterns are not easily identifiable with these maps. Hence, local characterization of the activation wavefront propagation can be helpful for improving VT and AT diagnosis. The purpose of this thesis is to develop a method to locally characterize the activation wavefront propagation. For that, a conduction velocity vector field is estimated and analyzed. The method was first validated on a simulated database from computer models, then applied to 1) a clinical database obtained from ECGi to localize infarct tissues and improve AT diagnosis ; and 2) a clinical database acquired with electro-anatomical mapping systems to define pathological areas