Diltiazem Protocol

PROTOCOL:   Calcium Channel Blocker use of Intravenous Diltiazem during Cardiac CT Angiography (CCTA)

Purpose: To decrease patient's heart rate and reduce r-r interval variability for improved image quality from cardiac CT scans of the coronary arteries is those patients in whom beta-blockers are contraindicated.


·          2nd degree or greater A-V block, sick sinus syndrome

·          Decompensated Congestive Heart Failure

·          Severe aortic stenosis

·          Prior allergic or severe adverse reaction to Diltiazem

Relative contraindications:

·         1st degree AV block with PR interval >/= 0.24sec

·         Systolic blood pressure less than 100 mm Hg

·         Heart rate less than 60 bpm

·         Left ventricular systolic dysfunction


I.          Oral Diltiazem

1. Obtain baseline resting heart rate and blood pressure.  For all patients consider anxiety level, BMI, clinical and medical history in selecting doses and consult with physician if there are questions/concerns.  For patients in whom beta-blockers are contra-indicated:

             If 60<HR<65 give Diltiazem 120 mg orally.


             If 65<HR<80 give Diltiazem 240 mg orally.


            If HR>80 and beta blockers are contra-indicated, contact MD


II.        Intravenous Diltiazem

If heart rate > 60 and blood pressure >100 systolic 60 minutes after oral medication and beta-blockers are contra-indicated, then:


1. Give Diltiazem 10mg IV slowly over two (2) minutes.

2. Monitor and record patient's heart rate every one (1) minute and blood pressure every 3 minutes x 6 minutes


3.  Wait 10 minutes in between each dose.

4. Continue to administer Diltiazem 5 mg IV every 10 minutes until heart rate <60 or cumulative IV dose equals 20 mg or blood pressure <100 systolic.