Atrial fibrillation is the most common cardiac rhythm disorder observed in clinical practice. It carries high morbidity and mortality rates, primarily related to heart failure, stroke and death. Validation of noninvasive markers in the diagnosis of heart failure with preserved ejection fraction and risk stratification is relevant in this clinical setting. The spectral tissue Doppler-derived E/e’ ratio is a simple and reproducible index, which has been validated in noninvasive assessment of left ventricular diastolic pressures, regardless of rhythm. Septal E/e’ >11 is a good predictor of invasively determined left ventricular diastolic pressure >15 mmHg in patients with atrial fibrillation. Several studies have validated the clinical relevance of abnormal values for E/e’ at rest and during exercise in the diagnosis and risk stratification of heart failure with preserved ejection fraction in patients with atrial fibrillation. Increased E/e’ value is associated with adverse outcome (death, left atrial appendage thrombus, stroke and heart failure) in patients with atrial fibrillation and predicts arrhythmia recurrence after cardioversion and catheter ablation. In conclusion, E/e’ by spectral tissue Doppler is clinically relevant in the clinical management of any patients with atrial fibrillation referred for transthoracic Doppler echocardiography.