francisco.clj

;;;; francisco.clj
(ns francisco
  (require [francisco.pacemaker :as pacemaker]))

(atom current-state-of-being
  {:alive true             
   :body-parts {:heart {:current-heart-rate (rand-int 100)}}})

(while (:alive current-state-of-being)
  ; ...
  (pacemaker/dont-let-heart-stop (get-in [:body-parts 
                                :heart] 
                               current-state-of-being))
  ; ...
  )

pacemaker.clj

;;;; francisco.pacemaker.clj
(ns francisco.pacemaker)

(def min-heart-rate 45)

(defn get-heart-rate [heart]
  (:current-heart-rate heart))

(defn poke-the-heart-with-a-bit-of-electricity [heart]
  (assoc heart :current-heart-rate (inc (get-heart-rate heart))))

(defn dont-let-heart-stop [current-heart]
  (let [current-heart-rate (get-heart-rate current-heart)]
    (when (<= min-heart-rate current-heart-rate)
      (poke-the-heart-with-a-bit-of-electricity))))