Sick Sinus Syndrome
                        ===================

þ Causes of SSS:
 - Digitalis, quinidine, beta-blockers, and aerosol propellants all can cause
   a temporary sick sinus syndrome.
   [Marriott, Practical Electrocardiography 8th ed. p 356]

þ Definition and Natural History
 - The sick sinus syndrome is any form of sinus nodal depression -
   - marked bradycardia, sinus arrest, or sinus block.

þ "Tachy-brady" Syndrome
 - can be seen as a special subset of sick sinus syndrome in which the periods
   of sinus node depression alternate with bursts of atrial tachycardia
   (often atrial fibrillation).
   [Marriott, Practical Electrocardiography 8th ed. p 356]