Page 2414 - Hematology_ Basic Principles and Practice ( PDFDrive )

2154 Part XII Hemostasis and Thrombosis

Mitral valve

Left atrium
Left atrium
Left atrial appendage

Left ventricle
cavity

Left atrial appendage
thrombus in AF

Fig. 147.1 LEFT ATRIAL APPENDAGE AND THROMBUS. The top panel shows the left atrial appendage
(LAA) using two orthogonal planes from a mid-esophageal view using transesophageal echocardiography. The
bottom panel shows the same view taken after the patient was found to be in atrial fibrillation (AF), with a
large clot arising from the LAA and extending into the body of the left atrium.

cardiac function. Digoxin has not been tested in randomized trials in In brief, all antiarrhythmic drugs have the potential for side effects
AF, but in heart failure with sinus rhythm, digoxin reduces symptoms (e.g., thyroid dysfunction and pulmonary fibrosis with long-term
and hospital admissions without affecting mortality. Digoxin is often amiodarone use, and the proarrhythmic effects of class I antiarrhyth-
useful as adjunctive therapy in patients with ongoing symptoms and mics). However, in selected patients, they can be helpful to restore
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uncontrolled heart rates. Conventional approaches to target to a strict and maintain sinus rhythm. Direct current electrical cardioversion
heart rate (<80 beats/min) have not proved to be better than a more is an effective method to achieve rhythm control, although patients
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lenient approach, both for prognosis and symptom control. Hence will require heavy sedation/anesthetic, and recurrence of AF is
in most patients, the heart rate should be kept at <110 beats/min, common. Catheter ablation of AF involves radiofrequency ablation
with uptitration of therapy if symptoms persist. or cryoablation to the endocardium, typically involving isolation
of the pulmonary veins (see box on Interventional Approach to
Atrial Fibrillation). Although direct evidence of improvement in
Rhythm Control long-term outcomes is pending, there are studies that suggest that
ablation improves symptoms and ejection fraction, even in patients
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The aim of rhythm control is to restore normal sinus rhythm and with AF and heart failure. Surgical ablation, either targeting the
improve symptoms (or heart function). This can be achieved using pulmonary veins or with the more extensive Cox-Maze approach,
antiarrhythmic drugs, electrical cardioversion, and catheter or surgi- is typically performed in patients undergoing cardiac surgery for
cal ablation. A full review of this expanding field is beyond the scope other reasons (e.g., valve replacement or coronary artery bypass
of this review, and readers are advised to refer to guideline documents, grafting). Regardless of the method of rhythm control, there
which are frequently updated (http://www.escardio.org/guidelines/ remains a risk of recurrent (often asymptomatic) AF, and clinicians
clinical-practice-guidelines/atrial-fibrillation-management). should not stop long-term anticoagulation in patients with risk