Hyoscyamine Subs for Pacemaker in Afib with Bradycardia

— When administered four times a day, according to a case study

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An anticholinergic drug can be administered in place of pacemaker placement in patients who have atrial fibrillation (Afib) with bradycardia, physicians learned from the case of a 98-year-old man in Florida.

As described in a case report in the , the patient arrived at the emergency department with blood pressure at 72/40 mm Hg and a heart rate of 35 beats per minute. The ECG showed Afib with a slow ventricular response and right bundle branch block. Although symptomatic bradycardia is normally treated with a pacemaker, the doctors opted for a medication-only approach given the man's condition.

The authors of the report, Scott Helgeson, MD, and colleagues at Mayo Clinic in Jacksonville, Fla., wrote that they started the patient, who had dementia, on 0.5 mg IV atropine, which increased his heart rate and blood pressure to 50 beats/min and 118/73 mm Hg. The next day, 0.1 mg IV glycopyrrolate got his heart rate up from 50 to 73 beats/min for 30 minutes, after which sublingual, immediate-release hyoscyamine (0.125 mg) produced a similar but more prolonged response.

The patient did not develop tachyarrhythmia overnight and was discharged the next day with a resting heart rate of 70-80 beats/min while receiving the same dose of hyoscyamine four times a day. At 4-week follow-up, he reported no syncope, and a repeat ECG showed a resting heart rate of 73 beats/min.

The authors called this the first report of hyoscyamine or any other anticholinergic drug being used to avoid pacemaker placement in a patient with symptoms caused by a slow ventricular response during Afib.

"This patient was a poor candidate for a pacemaker because of his dementia. This condition prevented him from following the activity restrictions required after pacemaker placement to avoid lead dislodgement, including arm raising and weight bearing on the side of pacemaker implantation for 2 to 4 weeks. The patient also used a walker, which would involve upper extremity weight bearing and could have strained the ipsilateral pectoralis major and increased the risk for lead dislodgement."

Pending further study into this strategy, Helgeson et al said, clinicians may want to try hyoscyamine in Afib patients who have a slow ventricular response but comorbidities that make pacemaker therapy less desirable.

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    Nicole Lou is a reporter for , where she covers cardiology news and other developments in medicine.

Disclosures

Helgeson disclosed no relevant conflicts of interest.

Primary Source

Annals of Internal Medicine

Helgeson SA, et al "Hyoscyamine for a slow ventricular response during atrial fibrillation" Ann Intern Med 2018