What is the appropriate preoperative evaluation for a patient undergoing colonoscopy with a history of hypertension and electrocardiogram (ECG) findings of right bundle branch block (RBBB) and left anterior fascicular block (LAFB)?

From the Guidelines

For a patient with hypertension and bifascicular block (right bundle branch block and left anterior fascicular block) undergoing colonoscopy, a focused preoperative evaluation is appropriate, with no additional cardiac testing necessary in the absence of symptoms or other cardiac disease, as recommended by the 2014 ACC/AHA guideline on perioperative cardiovascular evaluation and management of patients undergoing noncardiac surgery 1. The patient should have a recent blood pressure measurement to ensure hypertension is controlled (ideally <160/90 mmHg) as suggested by the 2007 ACC/AHA guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery 1. A 12-lead ECG within 3 months is sufficient to document the known conduction abnormalities, as routine preoperative resting 12-lead ECG is not useful for asymptomatic patients undergoing low-risk surgical procedures, according to the 2014 ACC/AHA guideline 1. Basic laboratory tests including electrolytes, BUN, creatinine, and complete blood count are recommended to assess renal function and rule out electrolyte abnormalities that could worsen conduction issues. The patient should continue their antihypertensive medications through the morning of the procedure, taking them with a small sip of water, except for diuretics which should be held the morning of the procedure, as recommended by the 2007 ACC/AHA guidelines 1. During the procedure, careful attention should be paid to fluid status and electrolyte balance, as dehydration from bowel preparation can exacerbate conduction abnormalities. The bifascicular block itself is not a contraindication to colonoscopy, but the endoscopy team should be made aware of this finding as it represents a higher risk for developing complete heart block under sedation, though this risk remains low in asymptomatic patients, as noted in the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1. Some key points to consider in the evaluation and management of this patient include:

• The importance of controlling hypertension preoperatively to reduce the risk of perioperative cardiac complications, as emphasized by the 2007 ACC/AHA guidelines 1
• The role of electrocardiography in diagnosing potential conduction disorders, as discussed in the 2018 ACC/AHA/HRS guideline 1
• The potential benefits and risks of continuing antihypertensive medications during the perioperative period, as noted in the 2007 ACC/AHA guidelines 1
• The need for careful attention to fluid status and electrolyte balance during the procedure to minimize the risk of exacerbating conduction abnormalities, as recommended by the 2014 ACC/AHA guideline 1.

From the Research

Preoperative Evaluation for Colonoscopy

The patient in question has a history of hypertension but no other cardiac disease, and presents with right bundle branch block and left anterior fascicular block on EKG.

• The patient's EKG findings are indicative of a conduction abnormality, which may be associated with underlying heart disease 2, 3.
• However, the presence of right bundle branch block and left anterior fascicular block does not necessarily imply a high risk for complications during colonoscopy 4, 5.
• The patient's history of hypertension is a significant factor, as it may be associated with an increased risk for conduction system disease 6.
• The use of certain medications, such as lisinopril, may be beneficial in reducing the risk for conduction system disease 6.

Recommendations for Preoperative Evaluation

• A thorough medical history and physical examination should be performed to assess the patient's overall health and identify any potential risks for complications during colonoscopy.
• An EKG should be performed to confirm the presence of right bundle branch block and left anterior fascicular block, and to assess for any other conduction abnormalities.
• The patient's hypertension should be well-controlled prior to colonoscopy, and the use of medications such as lisinopril may be beneficial in reducing the risk for conduction system disease.
• The patient should be closely monitored during colonoscopy for any signs of cardiac complications, and appropriate measures should be taken to minimize the risk for adverse events.