A 45-year-old Japanese man with paroxysmal atrial fibrillation (AF) developed 
acute anteroseptal myocardial infarction (MI). He had used 1% topical minoxidil 
(RiUP) once a day for 4 months before the onset of MI for treatment of baldness. 
Coronary angiography demonstrated severe stenosis at the proximal portion of the 
left anterior descending coronary artery with a tilling defect. 
Electrocardiographic monitoring revealed paroxysmal AF and sinus bradycardia 
with sinus arrests, suggestive of sick sinus syndrome. Topical minoxidil is now 
widely used for the treatment of male pattern baldness. Although it may be 
difficult to relate topical use of minoxidil to myocardial ischemia, a greater 
awareness of its toxicity will be necessary, and patients with cardiovascular 
disorders should be excluded from the therapy.