Thesis (M.D.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 246-315).

Thesis (M.D.)--University of Hong Kong, 1997. / Includes bibliographical references (leaf 246-315) Also available in print.

La Fibrilación Auricular constituye la arritmia más frecuente vista en los servicios de emergencia. La amiodarona constituye una estrategia de tratamiento eficaz como cardiovertor químico en la fibrilación auricular, siendo su uso cada vez mayor por sus excelentes cualidades. El propósito del presente trabajo fue evaluar la eficacia de la amiodarona en la cardioversión de arritmias auriculares a ritmo sinusal de reciente inicio. Se estudiaron 40 pacientes ingresados al Servicio de Emergencia del Hospital Militar Central, con diagnóstico de fibrilación auricular de reciente inicio, usando la amiodarona por vía endovenosa, observando una cardioversión química exitosa en el 87.5% de los pacientes, siendo el medicamento bién tolerado, no hallándose efectos adversos o de importancia. Por lo tanto la amiodarona endovenosa constituye un eficaz cardiovertor químico de la fibrilación auricular de reciente inicio respaldado con diversos estudios. Es una droga bien tolerada. / --- Atrial Fibrilation is a frequent arrhytmia. A therapeutic option for this pathology is quimic cardioversion. The objective of this study was to investigate the efficacy of intravenous amiodarona in recent onset atrial fibrilation. We studied 40 patients who where admitted to the emergency department with diagnostic of recent onset atrial fibrillation who recibed intravenous amiodarone. Quimic cardioversion was achieved in 87.5% of them, with good tolerance and side effects presenting in 10 % of the patients. Conclusion: the precocious therapy with intravenous amiodarona as a quimic cardiovertor is effective and well tolerated. Amiodarone is well tolerated as a precocious treatment for quimic cardioversion in patients with atrial fibrillation. / Tesis de segunda especialidad

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BACKGROUND: AF is a growing epidemic in the United States that will continue to worsen as risk factors become more prevalent in the population. The arrhythmia often persists asymptomatically before presenting as a stroke or when the disease has progressed to cause permanent cardiac restructuring. The gold standard for diagnosis is ECG. The current treatment consists of rate control, rate control, and stroke prevention with anticoagulation. LITERATURE REVIEW: Recent studies have shown that screening for AF does result in an increase in AF diagnosis. A current gap in literature remains regarding if that increase in AF diagnosis leads to a stroke reduction in the screened population. PROPOSED PROJECT: The proposed project is a randomized control trial that will compare AF diagnosis in a control group to a group that is screened for AF using a 30-day cardiac monitor. The statistical analysis will reveal if there is a reduction in stroke and other cardiac sequelae in the screened group compared to the control group. CONCLUSION/SIGNIFICANCE: Should the study reveal that screening for AF in an at-risk population reduces the risk of stroke, it could assist the USTF in addressing the gap in literature required to either recommend for or against AF screening in the United States.

Atrial fibrillation is a common arrhythmia encountered in the emergency department. In the United States, newly diagnosed cases of atrial fibrillation is projected to be 2.6 million cases in 2030 and the annual prevalence of atrial fibrillation is expected to be 12.1 million in 2030 (Colilla et al., 2013). Patients may present to the emergency department for treatment of atrial fibrillation with a variety of symptoms and therefore makes diagnosing atrial fibrillation based on symptomatology challenging for the clinician. The primary goal of this Doctor of Nursing Practice (DNP) project is to describe symptoms of atrial fibrillation in patients that seek medical treatment in the emergency department. Methods: This descriptive study contains secondary analysis of existing data derived from structured interviews that took place at two academic medical centers. This analysis included 74 patients that presented to the emergency department with symptoms suspected of acute coronary syndrome and were later diagnosed with atrial fibrillation. Descriptive statistics were used to synthesize data, while inferential statistics (bivariate tests) were used to compare symptoms between the age groups. Results: The mean age of subjects was 70 + 13 years, ranging 31 to 92 years. The majority of subjects were men (75.7%) and whites (90.5%). The most common symptoms reported by study subjects included chest discomfort (n = 50; 67.6%), followed by generalized weakness (n = 39; 52.7%) and shortness of breath (n = 39; 52.7%), and palpitations/ funny beating of the heart (n = 36; 48.6%) and unusual fatigue/ tiredness (n = 36; 48.6%). Sweating was the only symptom that was statistically significant in the younger adult group than in the older adult age group. Conclusion: The symptoms identified in this DNP project can be used to aid in identifying patients that present to the emergency with symptomatic atrial fibrillation. Further efforts for the assessment of atrial fibrillation should focus on the dissemination of common although nonspecific symptoms to facilitate the inclusion of atrial fibrillation as part of the differential diagnosis.

INTRODUÇÃO: O aumento da proporção de idosos implica estudar os determinantes dos principais agravos associados ao envelhecimento como a demência, principalmente a associada à doença cerebrovascular. Um fator de risco relevante para doença cerebrovascular é a freqüência de fibrilação atrial crônica. O São Paulo Health and Ageing Study com base populacional para estudo de distúrbio cognitivo e demência é uma oportunidade única para verificar a prevalência de fibrilação atrial e de sua associação com demência. MÉTODOS: Estudo transversal, por arrolamento de 1524 idosos com 65 anos ou mais estudo acima, no distrito do Butantã, cidade de São Paulo. O diagnóstico de fibrilação atrial foi feito com o eletrocardiograma de repouso de doze derivações e o de demência foi feito utilizando-se o protocolo do Research Group of Dementia 10/66. Estudaram-se variáveis sócio-econômicas e fatores de risco cardiovascular como hipertensão, diabetes, dislipidemia e obesidade. RESULTADOS: A amostra estudada tinha idade média de 72,2 anos, era predominantemente feminina, branca, casada, de baixa escolaridade e renda. A prevalência de fibrilação atrial associou-se ao aumento da idade e foi de 1,9% para o sexo feminino e 3,1% para o sexo masculino, com prevalência para ambos os sexos ajustada para idade de 2,7%. A prevalência de demência também se associou ao aumento da idade e sua prevalência idade ajustada foi de 4,9%, maior em mulheres (4,8%) do que em homens (3,6%). A razão de chances ajustada para idade para a associação de fibrilação atrial e demência foi de 2,88 (Intervalo de Confiança, IC 95% - 0,98 8,40) para ambos os sexos sendo e, de 1,50 (IC95% - 0,19 11,83) para homens e 4,48 (IC95% - 1,23 16,29) para mulheres. Encontrou-se maior risco de demência entre mulheres com fibrilação atrial (17,7%) do que entre os participantes do mesmo sexo sem demência (4,6%) Outras alterações no eletrocardiograma de repouso com interesse foram determinadas como com área inativa (código de Minnesotta q1- q2) de: 9,1% nas mulheres e 16,6% nos homens; e também bloqueio de ramo esquerdo de 3,3%, nas mulheres 3,0% e nos homens 3,6%. CONCLUSÃO: Mulheres idosas com fibrilação atrial têm diagnóstico de demência quase quatro vezes mais do que aquelas em ritmo sinusal / INTRODUCTION: The growing aging population proportion makes us study the most important illness related with aging of the population as dementia, specially the dementia associated to stroke. Atrial fibrillation is a main risk factor with cerebrovascular disease. The São Paulo Heath and Ageing Study a population based study for cognitive disturb and dementia is an unique opportunity to verify the atrial fibrillation prevalence and its association with dementia. Methods: This is a cross-sectional study. The population of this study was composed by 1,524 elderly people, over 65 years of age, covered by the Health Program Family in the Butantã district, São Paulo, who were recruited door by door. The diagnosis of atrial fibrillation was made using a twelve lead resting electrocardiogram and the diagnosis of dementia was made by the protocol of Research Group of Dementia 10/66. We studied socio economic variables and cardiovascular risk factors as hypertension, diabetes, dislipidemia and obesity. RESULTS: The studied population had a mean age of 72.2 years old and was predominantly female, white, married and of low educational and financial status. We found that atrial fibrillation prevalence increased throughout age-strata and was of 1.9% among the females and 3.1% among the males, and age-adjusted prevalence of 2.7%. The prevalence of dementia also increases with age and its ageadjusted prevalence was of 4.9%, greater among the females (4.8%) than among the males (3.6%). The odds ratio age-adjusted for the association of atrial fibrillations and dementia was of 2.88 (Confidence interval, 95% CI 0.98 8.40) for both sex: 1.50 among men (95% CI 0.19 11.83), and 4.48 among women (95% CI 1.23 16.29). We found a higher risk of dementia among the female with atrial fibrillation (17.7%) than among female participants without atrial fibrillation (4.6%). Other resting electrocardiogram alterations were determined as previous inactive areas (Minnesotta Code q1-q2) of 12.4%: among the females of 9.1% and among the males of 16.6%. The frequency of left bundle-branch block was of 3.3%: among the females of 3.0% and among the males of 3.6% .CONCLUSION: Elderly women with atrial fibrillation had the diagnosis of dementia almost four times greater than that of women with sinus rhythm

The Objectives of this thesis are: 1) To study possible atrial interaction in patients with right and left ventricular outflow tract obstruction due to significant pulmonary (PS) and aortic valve stenosis (AS), respectively. 2) To assess left atrial (LA) intrinsic myocardial function and its relationship to indirect measures of left ventricular (LV) filling pressures in patients with paroxysmal atrial fibrillation (PAF). 3) To test the hypothesis that the LA function is affected in patients with pulmonary arterial hypertension (PAH). 4) To test the hypothesis that raised LA pressure as shown by pulmonary capillary wedge pressure (PCWP) correlates with severity of LA intrinsic systolic function. We conducted 4 studies to achieve the objective sabove. Study I Methods: We studied 41 PS patients (age 36±10 year) and 41 AS patients (age 35 ± 12 year) and compared them with 27 controls (age 30 ± 7 year). RV and LV filling were recorded by conventional PW Doppler. Biventricular segmental function was studied using the PW tissue Doppler imaging (TDI) and M mode techniques. Results: The 2 patient groups had similar degree of ventricular outflow tract obstruction. In the pressureoverloaded ventricle, global systolic function was preserved but long axis function was impaired.Patients had higher peak late filling (Awave)and TDI late diastolic (a’) velocities recorded in the disease free ventricles despite having similar peak early filling velocities (E wave), E wave deceleration time and E/e’ ratios were not different from controls (p>0.05 for all). The accentuation of atrial activity (A wave) was moderately correlated with the degree of contra lateral ventricular outflow tract obstruction (p<0.001 for both). Conclusion: In the pressure overloaded ventricle long axis function is more sensitive than global function in revealing myocardial dysfunction. The increased contra lateral atrial systolic activity suggests an evidence for atrial interaction in the form of ‘Cross Talk’. Study II Methods: Twentyfive PAF patients (age 68±7 year, 10 males) with Doppler signs of raised filling pressures were studied using speckle tracking echocardiography and compared with 21 controls. LA segmental longitudinal strain (S), strain rate (SR) and myocardial velocities during atrial systole were measured as were LA longitudinal and transverse diameters. Markers of LV filling pressures were E/A andE/e’. Results: LA longitudinal diameter was larger in patients (5.5±0.6 vs. 4.8±0.6cm,p<0.01) and global LAS and SR were reduced (p<0.05 for both) and correlated with E/A (r=0.52 and r=0.43, p<0.05 for both). LA segmental S and SR were uniformly reduced compared with controls (p<0.05 for all) and also correlated with E/A (p<0.05 for all). LA myocardial velocities (TDI) were highest at the annular level and lowest at the rear in both patients and controls (p<0.01 for all), with the absolute values at each level not different between groups. Myocardial velocities negatively correlated with E/A at the annular level only in patients (septal: r=0.52; lateral: r=0.62, p<0.01 for both). Conclusion: In PAF patients, LA systolic function is suppressed and is directly related to the raised filling pressures. While intrinsic global and segmental function can reproducibly be studied by S and SR, myocardial velocities reflect only regional motion. These findings provide a sound explanation to the known beneficial effect of vasodilators in PAF patients. Study III Methods: We studied LA size and reservoir function in 35 patients (age 63 ± 15 years, 16 male) with idiopathic PAH using speckle tracking echocardiography who also underwent right heart catheterization simultaneously to assess pulmonary artery systolic pressure, and compared them with 27 age and gender normal controls. Results: In PAH patients, LA longitudinal diameter was not different from controls but transverse diameter was reduced (3.0 ± 0.6 vs. 3.7 ± 0.5cm, p<0.001). LA lateral wall strain rate (SR) during LV systole (atrial reservoir function was reduced at annular (p<0.001) and mid cavity (p<0.01) levels as were septal segments (p<0.03, for both) compared to controls. Opposite to controls, the two LA walls responded differently to right heart pressures. Lateral SR inversely correlated with pulmonary artery systolic pressure (PASP) (annular: r=0.45, p<0.005 and midcavity: r=0.43, p<0.01), but not with right atrial pressure (RAP). In contrast, septal SR inversely correlated with RAP (annular: r=0.39, p=0.02 and midcavity: r=0.38, p=0.03) but not with PASP. Conclusion: In patients with PAH, LA reservoir function is significantly impaired showing reduced myocardial strain rate properties. In addition,segmental function differs in their response to raised right heart pressures with the septal wall related to right atrial pressure and lateral wall related to the PASP. These findings suggest an evidence for atrial interaction in PAH, which is likely to have significant impact on LV performance. Study IV Methods: We studied 46 patients, mean age 61 ± 13 years, 17 males, of various etiologies with exertional breathlessness who underwent right heart catheterization and simultaneous transthoracic Doppler echocardiography using spectral, tissue Doppler and speckle tracking echocardiography techniques for assessing LA structure and function. Results: PCWP correlated with direct measurements of LA structure and function: LA volume (r= 0.43, p<0.01), LA global systolic strain rate (r=0.79, p<0.001) and to a lesser extent with LA systolic filling fraction (r=0.52, p<0.001). PCWP also correlated with indirect measures of LA pressure: LV E/A (r=0.66, p<0.001), E wave deceleration time (r=0.54, p<0.001), lateral E/e’ (r=0.49, p<0.001) and LV isovolumic relaxation time (r=0.36, p<0.01). LA strain rate was 78% sensitive and 84% specific in identifying patients with PCWP>15 mmHg, having accurately predicted PCWP in 63% of the cases. Conclusion: PCWP correlates with LA intrinsic systolic function and to a much lesser degree with indirect Doppler measures of raised LV filling pressures. These findings should have significant clinical implications in identifying breathless patients with raised LA pressure.