Obstructive sleep and atrial fibrillation: Pathophysiological mechanisms and therapeutic implications.

Atrial fibrillation (AF) is the commonest arrhythmia in clinical practice and is associated with increased cardiovascular morbidity and mortality. Obstructive sleep apnea (OSA), a common breathing disorder, is an independent risk factor for AF. Several pathophysiological mechanisms, including apnea-induced hypoxia, intrathoracic pressure shifts, sympathovagal imbalance, atrial remodeling, oxidative stress, inflammation and neurohumoral activation have been implicated in the occurrence of AF in OSA patients. In addition, OSA has been shown to reduce success rates of antiarrhythmic drugs, electrical cardioversion and catheter ablation in AF. Effective prevention of obstructive respiratory events by continuous positive airway pressure ventilation (CPAP) reduces sympathovagal activation and recurrence of AF. The present review describes the relationship between OSA and AF, presents the pathophysiological mechanisms implicating OSA in AF occurrence, and provides an update of the potential therapeutic interventions for patients with OSA and AF.

Usefulness of low-dose dobutamine stress echocardiography for the evaluation of spontaneous recovery of stunned myocardium in patients with acute right ventricular infarction.

Right ventricular (RV) infarction (RVI) is usually associated with severe RV global dysfunction representing predominantly stunned myocardium that may respond favorably to reperfusion. We assessed the efficacy of low-dose dobutamine stress echocardiography (DSE), performed early in the course of a reperfused RVI, to predict the recovery of RV systolic and diastolic function in 3 months, documenting the recovery of stunned myocardium. In all, 27 patients with acute, successfully thrombolyzed RVI comprised the study population. All patients underwent standard echocardiography at baseline and 3 months later for evaluation of RV systolic and diastolic function. At day 5 DSE was performed for evaluation of RV contractile reserve. Of the total number of segments analyzed, 69% were detected as stunned. At baseline, RV systolic and diastolic indices were seriously impaired showing significant improvement at follow-up. RV wall-motion score index during DSE was positively correlated with the same index at follow-up. DSE is a safe and precise modality to predict recovery of stunned myocardium in the setting of RVI.

Atrial Fibrillation in Athletes.

Atrial fibrillation is the most common arrhythmia in athletes and may be associated with endurance sport practice. Atrial ectopic beats, chronic systemic inflammation, autonomic system alterations, anatomic adaptation, myocardial injury and illicit drugs seem to be implicated in the increased prevalence of atrial fibrillation in athletes, but clear evidence is lacking. Treatment of the arrhythmia is a challenging issue, as atrial fibrillation may impair athletic performances and deteriorate athletes' quality of life. This review focuses on the epidemiology, possible pathophysiological mechanisms, and management of atrial fibrillation in athletes.

Obesity and atrial fibrillation: A comprehensive review of the pathophysiological mechanisms and links.

Obesity is a worldwide health problem with epidemic proportions that has been associated with atrial fibrillation (AF). Even though the underlying pathophysiological mechanisms have not been completely elucidated, several experimental and clinical studies implicate obesity in the initiation and perpetuation of AF. Of note, hypertension, diabetes mellitus, metabolic syndrome, coronary artery disease, and obstructive sleep apnea, represent clinical correlates between obesity and AF. In addition, ventricular adaptation, diastolic dysfunction, and epicardial adipose tissue appear to be implicated in atrial electrical and structural remodeling, thereby promoting the arrhythmia in obese subjects. The present article provides a concise overview of the association between obesity and AF, and highlights the underlying pathophysiological mechanisms.

Diabetes mellitus and atrial fibrillation: Pathophysiological mechanisms and potential upstream therapies.

Diabetes mellitus (DM) represents one of the most important risk factors for atrial fibrillation (AF) while AF is a strong and independent marker of overall mortality and cardiovascular morbidity in diabetic patients. Autonomic, electrical, electromechanical, and structural remodeling, including oxidative stress, connexin remodeling and glycemic fluctuations seem to be implicated in AF pathophysiology in the setting of DM. The present review highlights the association between DM and AF, provides a comprehensive overview of the responsible pathophysiological mechanisms and briefly discusses potential upstream therapies for DM-related atrial remodeling.

Echocardiographic evaluation of spontaneous recovery of right ventricular systolic and diastolic function in patients with acute right ventricular infarction associated with posterior wall left ventricular infarction.

We evaluated right ventricular (RV) systolic and diastolic function in 30 patients with acute RV myocardial infarction on echocardiography. Systolic and diastolic function were impaired early in the setting of RV myocardial infarction, but improved significantly at 3 months.