In general, should people with high normal heart rate not be prescribed ssri's due to increased norepinephrine effect?

No -- incorrect: Ssri's affect serotonin reuptake only. There are some like effexor, cymbalta, and pristiq, (desvenlafaxine) which have additional effects beyond serotonin -- these are technically "snris" (serotonin-norepinephrine reuptake inhibitors). Reports of tachycardia are rare with ssri's, and can happen with snri's. BP can also be affected with snri's. These effects need monitoring, but ssri's ; snri's can be safe.