Anatomy and physiology of the atrioventricular node The atrioventricular node (AVN) is the only normal electrical connection between the atria and the ventricles; the fibrous skeleton acts as an insulator to prevent electrical impulses from entering the ventricles by any…
Anatomy and physiology of the sinus node The sinus node is a crescent-shaped, subepicardial specialized muscular structure located posterolaterally in the right atrial (RA) free wall. The sinus node lies within the epicardial groove of the sulcus terminalis, at the…
Risk of thromboembolism Atrial fibrillation (AF) is a major risk factor for thromboembolism, causing approximately 15% of the ischemic strokes in the United States, 36% of strokes in patients older than 80 years, and up to 20% of cryptogenic strokes.…
Management of atrial fibrillation (AF) should be aimed at identifying and treating underlying causes and predisposing conditions of the arrhythmia, as well as reducing symptoms, improving quality of life, and preventing cardiovascular morbidity and mortality associated with AF. There are…
Clinical presentation Symptomatic atrial fibrillation Atrial fibrillation (AF) can be symptomatic or asymptomatic, even in the same patient. Symptoms associated with AF vary, depending on the ventricular rate, the underlying functional status, the duration of AF, the presence and severity…
Classification of atrial fibrillation Atrial fibrillation (AF) has been described as lone, idiopathic, nonvalvular, valvular, paroxysmal, persistent, or permanent. Each of these classifications has implications regarding mechanisms as well as response to therapy. At the initial detection of AF, it…
Pathophysiology Cardiac arrhythmias are a common problem in patients with congenital heart disease (CHD), particularly after they have undergone reparative or palliative surgical procedures. Atrial tachyarrhythmias are the most prevalent, with a lifetime risk of approximately 50%, regardless of the…
Pathophysiology Organized atrial tachycardias (ATs) are broadly categorized as either focal (centrifugal activation originating from a discrete site that incorporates automaticity, triggered activity, and microreentrant mechanisms) or macroreentrant (a relatively large reentrant circuit around a central obstacle). Depending on whether…
Organized atrial tachycardias (ATs) are broadly categorized as either focal or macroreentrant (see Table 12.1 ). Focal ATs exhibit a centrifugal activation pattern originating from a discrete site and can have automaticity, triggered activity, and microreentrant mechanisms (see Video 12.1…
Classification of atrial tachycardias Organized atrial tachycardias (ATs) are broadly categorized as either focal (originating from a small circumscribed area from which it spreads out generally centrifugally; Video 12.1 ) or macroreentrant (continuous, uninterrupted activation wavefront rotating around a relatively…