Every time your dose is altered by 80mg to one way or the other you must get a heart film. I would not recommend verapamil to anyone in a world where we have anti-inflammatory regimen (vitamin D), herbal protocol (liquorice root) and busting (MM, lsd, lsa). It's not used for it's regular uses (heart/blood pressure) not that much anymore because there are better/safer options . IMO 480mg per day is just about maximum for any kind of safe use for majority and even on those doses there usually eventually arises either a heart problem or problem with the response. I've been well over a thousand myself. Verapamil will have an impact for the rest of your life, no matter the dose. I agree with CHfather, do the D3 regimen instead. Good luck !