• Cardiac causes of sinus tachycardia
    • Myocardial ischemia
    • Heart failure
    • Pulmonary embolism.
  • Points favoring VT as the cause of wide complex tachycardia
    • AV dissociation (P waves dissociated from QRS)
    • Capture beats
    • Fusion beats
  • Ivabradine is a blocker of If, the pacemaker current.
  • Pause following a premature atrial complex may be
    • Non-compensatory- if SA node is reset
    • Less than fully compensatory- to account for time taken for the ectopic impulse to travel to the SA node to reset it
    • Fully compensatory- When SA node or surrounding tissues are refractory and hence SA node is not reset, but still, the next SA nodal impulse cannot be conducted due to block induced by the PAC
    • No pause- Interpolated PAC, when the SA node is not reset by the PAC and conduction of the next SA nodal impulse is not blocked by the PAC.
  • It is easier to control ventricular rate in atrial fibrillation than in atrial flutter due to more concealed conduction in the former.