Bradycardia in a Fit, 82-Year-Old Male
I was asked to help evaluate an 82-year-old man who was admitted to the hospital after falling off his bicycle. He was noted to be confused, though initially he had no other focal neurological findings. The patient was diagnosed as having a left subdural hematoma and subarachnoid hemorrhage. While he initially reported only a mild headache, over the next 12 hours his speech became garbled and he developed an inability to grasp items with his right hand. It was determined that he would benefit from surgery to relieve excess pressure that was thought to be compromising his brain function. Upon admission, the patient’s pulse was noted to be 51 beats per minute and his electrocardiogram revealed a sinus bradycardia with moderate left ventricular hypertrophy. Although it was hard to obtain a detailed history due to his cognitive state and degree of dysarthria, we learned that he was taking no regular medications, had no prior medical conditions, and had been physically very active, bicycling and exercising on a regular basis.
I thought it would be a good idea to review the problem of bradycardia. Bradycardia is defined as any slow heart rhythm with a rate under 60 beats per minute. While mean heart rates reportedly decrease with age, bradycardia is not a part of the normal aging process. Degenerative problems in the sinus node may lead to sinus bradycardia, sinus arrest, or sinus block. Sick sinus syndrome is associated with an abnormality in the sinus node or atrioventricular node, and slow or rapid heart rates may be present either alone or in combination. Ischemic heart disease may cause changes in the conduction system, and baroreceptor and autonomic abnormalities can also lead to sinus slowing or atrioventricular node block. Hypothyroidism, a problem commonly affecting the elderly, may be associated with bradycardia, and traumatic brain injury can lead to both tachycardia and bradycardia due to effects on the central nervous system. Bradycardia should be suspected in anyone presenting with symptoms of syncope, presyncope, dizziness, or palpitations; however, patients may be completely asymptomatic. It is important to determine if symptoms relate to time of day, position, or activity, or have been associated with any new medication.
Now back to the patient. I found him intriguing, as he reportedly was in great shape, exercising on a regular basis and without any significant past medical history—at least that he was able to report. Perhaps his moderate degree of left ventricular hypertrophy and his bradycardia were not pathological, but actually a result of physical conditioning, not what we usually see in an older male who most likely has coexisting hypertension and coronary artery disease. Could the bradycardia in this patient be purely from his training? Unfortunately, we had no records of his premorbid state to help us establish if the bradycardia was new.
I then remembered hearing a few of the nurses “chuckling” that “He was taking sildenafil citrate.” I learned that the patient had a girlfriend who told one of the nurses that “It was unlikely he was taking the medication in recent weeks since I was out of town.” Whether or not he was using this drug at this time, I chose to review the side-effect profile of sildenafil citrate and learned that sinus bradycardia is a reported side effect of this medication. While bradycardia is nowhere near as common a problem as hypotension, bradycardia has been associated with sildenafil use in 34 of 27,096 persons evaluated, or 0.13%.
At the time of this writing, the patient was in the operating room. Hopefully, he will make a full recovery. Whether sildenafil will prove to be the cause of his bradycardia or some other etiology will surface, his road to a full recovery will be a long one, and we can only hope that he will soon be well enough to discuss whether he should restart taking sildenafil.
Dr. Gambert is Professor of Medicine and Associate Chair for Clinical Program Development, Co-Director, Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Maryland School of Medicine, Director, Geriatric Medicine, University of Maryland Medical Center and R Adams Cowley Shock Trauma Center, and Professor of Medicine, Division of Gerontology and Geriatric Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.