09-08-2012, 11:07 AM
Cardiac Assist Devices
Cardiac Pacemakers.ppt (Size: 4.41 MB / Downloads: 354)
Pacemakers Today
Single or dual chamber
Multiple programmable features
Adaptive rate pacing
Programmable lead configuration
Internal Cardiac Defibrillators (ICD)
Transvenous leads
Multiprogrammable
Incorporate all capabilities of contemporary pacemakers
Storage capacity
Temporary Pacing Indications
Routes = Transvenous, transcutaneous, esophageal
Unstable bradydysrhythmias
Atrioventricular heart block
Unstable tachydysrhythmias
*Endpoint reached after resolution of the problem or permanent pacemaker implantation
Permanent Pacing Indications
Chronic AVHB
Chronic Bifascicular and Trifascicular Block
AVHB after Acute MI
Sinus Node Dysfunction
Hypersensitive Carotid Sinus and Neurally Mediated Syndromes
Miscellaneous Pacing Indications
Chronic AVHB
Especially if symptomatic
Pacemaker most commonly indicated for:
Type 2 2º
Block occurs within or below the Bundle of His
3º Heart Block
No communication between atria and ventricles
Chronic Bifascicular and Trifascicular Block
Differentiation between uni, bi, and trifascicular block
Syncope common in patients with bifascicular block
Intermittent 3º heart block common
AVHB after Acute MI
Incidence of high grade AVHB higher
Indications for pacemaker related to intraventricular conduction defects rather than symptoms
Prognosis related to extent of heart damage
Sinus Node Dysfunction
Sinus bradycardia, sinus pause or arrest, or sinoatrial block, chronotropic incompetence
Often associated with paroxysmal SVTs (bradycardia-tachycardia syndrome)
May result from drug therapy
Symptomatic?
Often the primary indication for a pacemaker
Hypersensitive Carotid Sinus Syndrome
• Syncope or presyncope due to an exaggerated response to carotid sinus stimulation
• Defined as asystole greater than 3 sec due to sinus arrest or AVHB, an abrupt reduction of BP, or both
Miscellaneous
Hypertrophic Obstructive Cardiomyopathy
Dilated cardiomyopathy
Cardiac transplantation
Termination and prevention of tachydysrhythmias
Pacing in children and adolescents
Indications for ICDs
Cardiac arrest due to VT/VF not due to a transient or reversible cause
Spontaneous sustained VT
Syncope with hemodynamically significant sustained VT or VF
NSVT with CAD, previous MI, LV dysfunction and inducible VF or VT not suppressed by a class 1 antidysrhythmic