<prompt> Combination use of beta blockers and calcium channel blockers cause -Hea blockHypeensionHypotensionAll  <response>: Ans. is a i.e., Hea block o CCBs verapamil, diltiazem have negative chronotropic effect SA node automaticity - hea rate and negative dromotropic effect 1AV node conduction. o b-blockers have similar effect by blocking b1 sympathetic receptors on hea normally stimulation of b1 receptors increases hea rate and conduction. o Simultaneous use of these drugs can cause marked bradycardia and AV block. Amongst CCBs, DHPs nefidipine can be used with b-blockers because DHPs have no direct negative chronotropic and dromotropic effect, rather they cause tachycardia by reflex sympathetic stimulation. 