Purpose: To decrease patient's heart rate and
reduce r-r interval variability for improved image quality of coronary artery
CTA.
Goal:
Achieve a heart rate of 50-60bpm.
Contraindications:
· Congestive heart failure (CHF)
· Significant asthma or bronchospasm who
have used an inhaler within the past 2 weeks
· Severe aortic stenosis
· Known hypersensitivity to metoprolol
· Systolic blood pressure less than 100 mm
Hg
· Heart rate less than 60 bpm
Relative contraindications:
· 1st degree av block with pr >/=
0.24sec
Procedure: Oral Metoprolol
1. Obtain baseline heart rate and blood pressure. For all patients consider anxiety level, BMI,
clinical and medical history before deciding on doses.
If
baseline > 60 bpm give metoprolol 50 mg orally.
If
baseline > 65 bpm give metoprolol 50-100 mg orally.
If
baseline > 70 bpm give metoprolol 100-150 mg orally.If baseline > 80 bpm give metoprolol 100-200 mg orally.
2. Check and document heart rate and bp q 15 minutes x 1 hour after oral
metoprolol is given
Procedure: Intravenous Metoprolol
If heart rate > 60 bpm
and bp >100 systolic 60 minutes after oral metolprolol then:
1. Give iv metoprolol 5mg iv slowly over two minutes; perform in CT room as
half-life is short.
2. Monitor and record patient's heart rate q 1 minute and bp q 3 minutes x 6
minutes - use continuous monitoring.
3. Continue to administer 5mg iv metoprolol q 5 minutes until heart rate <60
bpm or cumulative iv dose equals 30mg or bp<100 systolic.
Post Scan Procedure:
1. After scan completed monitor patient's heart rate and blood pressure q 5
minutes x three and than q 15 minutes if iv metoprolol administered- use
continuous ECG monitoring
2. Patients may be discharged when the following criteria are met:
resting heart rate >55bpm, free of adverse effects from metoprolol. For iv
metoprolol, document heart rate and blood pressure for at least 30 minutes post
procedure.
3. Notify physician for hr
<45 or if patient experiencing signs or symptoms of adverse effects such as:
dizziness, lightheadedness, syncope, hypotension, bronchospasm, wheezing,
difficulty breathing, shortness of breath, heart block.
