<prompt> Best treatment for a patient with first-degree hea block who presented with complaints of dizzinessAtropineIsoprenalineAdrenalinePacemaker  <response>: In general, no treatment is indicated for asymptomatic isolated first-degree atrioventricular AV hea block. For patients with marked first-degree AV block PR interval 300 msec, however, several uncontrolled trials have demonstrated symptomatic improvement with placement of a dual-chamber pacemaker, though there is little evidence suggesting improved survival. in patients with severe bradycardia or those with the possibility of progression to higher-degree AV block, medications eg, atropine, isoproterenol can be used in anticipation of inseion of a cardiac pacemaker. Ref Davidson 23rd edition pg 455 