Physiologic Vs. Ventricular Pacing--Which is More Appropriate for Your Elderly Patient?
Tawfic Nessim Abu-Zahra, BSc, MSc
Cardiac pacemakers are widely used to treat the symptoms of cerebral hypoperfusion and hemodynamic decompen-sation that are caused by bradycardia.1 Pacemaker implantation is indicated for diseases of the sino-atrial (SA or sinus) and the atrioventricular (AV) nodes. There are two different modes of cardiac pacing, ventricular and physiologic. Ventricular pacing involves the direct stimulation of the ventricular myocardium without interaction with the atria, whereas physiologic pacing stimulates either the atria alone (atrial pacing) or both the atria and ventricles together (dual pacing).
There are many theoretical reasons why physiologic pacing should be superior to ventricular pacing. Physiologic pacing maintains the synchrony of atrial and ventricular contraction and the dominance of the sinus node by stimulating both the atria and ventricles.2 Physiologic pacing may prevent the pacemaker syndrome--a collection of symptoms associated with the asynchronous contraction of the heart that occurs with ventricular pacing.2 In comparison to ventricular pacemakers, however, physiologic pacemakers are more expensive, and are more difficult to monitor.3
Despite the theoretical advantages of physiologic pacemakers, this mode of pacing is not widely used.