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caused by VT/VF as well as primary prevention in patients at risk of life-
threatening VT/VF.
■ The 2008 American College of Cardiology/American Heart Association/Heart
Rhythm Society (ACC/AHA/HRS) established guidelines for device-based
therapy of cardiac rhythm abnormalities include guidelines for ICD therapy.
Indications for ICD Therapy
Secondary prevention: Implantation of an ICD is recommended for the second-
ary prevention of death resulting from VT/VF in the following settings:
■ Patients with prior episode of resuscitated VT/VF or sustained hemodynam-
ically unstable VT in whom a completely reversible cause cannot be identi-
fied. This includes patients with a variety of underlying heart diseases and
those with idiopathic VT/VF and congenital long QT syndrome, but not
patients who have VT/VF limited to the first 48 hr after an AMI.
■ Patients with episodes of spontaneous sustained VT in the presence of heart
disease (valvular, ischemic, hypertrophic, dilated, or infiltrative cardiomy-
opathies) and other settings (i.e., channelopathies).
Primary prevention: Implantation of an ICD is recommended for the primary pre-
vention of life-threatening VT/VF in patients at risk of SCD from VT/VF who have
optimal medical management (including use of beta blockers and ACE-IS), including:
■ Patients with prior myocardial infarction (at least 40 days ago) and left ven-
tricular ejection fraction ≤30%.
■ Patients with cardiomyopathy, New York Heart Association functional class II
or III, and left ventricular ejection fraction <35%. Patients with nonischemic
cardiomyopathy generally require optimal medical therapy for 3 mo with
documentation of persistent left ventricular ejection fraction <35% at that
time. Recommended patients be evaluated at least 3 mo after revasculariza-
tion (CABG or stent placement).
Procedure
Refer to pacemaker insertion.
Management
Postop care: Refer to Pacemakers.

Cardiac Tamponade
Cardiac tamponade is the acute compression of the heart caused by excessive
fluid or blood in the pericardial space. This results in accumulated pressure in
the pericardial sac and affects the heart’s function, especially cardiac output.
Normal pericardial fluid volume = 10–30 mL, but a rapid accumulation of 50–100 mL
of fluid can be fatal. It is a medical emergency that can result in pulmonary
edema, shock, and death.
CV