Atrial fibrillation and its association to cardiac function and structure in cardiovascular disease

University dissertation from Stockholm : Karolinska Institutet, Dept of Clinical Sciences, Danderyd Hospital

Abstract: Title: Atrial fibrillation and its association to cardiac function and structure in cardiovascular disease Aim: To study associations between atrial fibrillation (AF) and echocardiographic measures of left atrial (LA) and left ventricular (LV) parameters in patients with underlying cardiovascular disease. Hypothesis: LA and LV dysfunction can predict AF in heart failure (HF) or ischemic stroke. Background: AF is a cardiac arrhythmia characterized by irregular ventricular rhythm caused by permanent or paroxysmal loss of normal sinus node function. AF is prevalent (3%) and rises sharply with age and with increasing severity of HF (40-60%). Methods: Study I: Elderly patients with chronic HF (n=67)were retrospectively analysed for LV systolic and diastolic function: Study II: Patients with an ischemic stroke/TIA (n=174) without known AF were prospectively analysed by echocardiography including Tissue Doppler Imaging (TDI) for LA and LV function. Electrocardiographic screening was used during follow up to detect AF. Results: Study I: AF was found in 41 patients (61%). Ejection fraction was higher (p<0.01), LV volume indices were smaller (p<0.001) and LV concentric hypertrophy was more common (p<0.05), transmitral early wave deceleration time was shorter (p<0.05) and pulmonary S/D ratio lower (p<0.001) in AF compared to SR patients. Study II: AF was found in 15 patients (8.6%) during 30 days follow up. The AF patients had higher LA volume index (LAVI, p<0.05), lower peak velocities during atrial contraction (A´, p<0.05), and higher ratio LAVI/A´ (p<0.01). LAVI and LAVI/A´ predicted AF by ROC analysis (AUC 0.71-0.78). Conclusions: AF in chronic HF and ischemic stroke indicates a different patient population compared to normal rhythm with signs of diastolic dysfunction or abnormal LA function. Echocardiography using TDI can predict AF after ischemic stroke and gives an incremental value together with electrocardiographic methods to improve screening for AF.

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