Is a heart rate of 50 beats per minute (bpm) considered normal in a post-surgical patient?

From the Guidelines

A heart rate of 50 beats per minute (bpm) in a post-surgical patient is considered abnormal and requires immediate evaluation, as it falls below the typical normal range of 60-100 bpm and could indicate bradycardia, which is particularly concerning in the post-operative setting 1. The clinical significance depends on several factors including the patient's baseline heart rate, current symptoms, blood pressure, medication effects, and overall clinical status. Some patients, especially athletes or those on beta-blockers, may have a naturally lower heart rate. However, in the post-surgical context, a heart rate of 50 bpm could indicate complications such as a response to anesthesia, pain medications, electrolyte abnormalities, or developing cardiac issues.

Key Considerations

• The patient's symptoms, such as dizziness, confusion, weakness, or hypotension, should be assessed immediately 1
• Medication effects, particularly beta-blockers, should be considered as a potential cause of bradycardia 1
• Electrolyte abnormalities, such as hypokalemia or hyperkalemia, should be ruled out as a cause of bradycardia 1
• Developing cardiac issues, such as heart block or cardiac arrest, should be considered and promptly addressed 1

Recommendations

• Monitor vital signs closely and check the patient's medication list to identify potential causes of bradycardia 1
• Assess for signs of hemodynamic compromise, such as hypotension or decreased urine output, and address them promptly 1
• Consider obtaining an ECG to evaluate cardiac rhythm and identify potential cardiac issues 1
• Administer atropine or other chronotropic agents as needed to increase heart rate and improve cardiac output 1

From the Research

Heart Rate of 50 in a Post-Surgical Patient

• A heart rate of 50 beats per minute (bpm) is considered bradycardia, which is defined as a heart rate of less than 60 bpm 2.
• In a post-surgical patient, bradycardia can be a concern, as it can lead to decreased cardiac output and potentially compromise the patient's hemodynamic stability.
• The study by 2 compared the effectiveness of atropine, glycopyrrolate, and transesophageal atrial pacing for treating intraoperative bradycardia in patients receiving a standardized anesthetic.
• The results showed that transesophageal atrial pacing was more effective in increasing the heart rate to greater than 70 bpm compared to atropine and glycopyrrolate.

Risk Factors for Bradycardia in Post-Surgical Patients

• Age, sex, type of heart disease, preoperative left ventricular ejection fraction, cardiopulmonary bypass and aortic clamping duration, length of anesthesia, dopamine administration, and maximal level of CK and CK-MB were considered as risk factors for postoperative arrhythmias, including bradycardia 3.
• Dopamine administration, even in low renal dose, was associated with the number and severity of ventricular arrhythmias, including bradycardia.

Treatment of Bradycardia in Post-Surgical Patients

• Atropine is commonly used to treat hemodynamically unstable bradycardia in post-surgical patients 4, 5.
• The study by 4 found that approximately half of the patients who received atropine for compromising rhythms had either a partial or complete response to therapy.
• The study by 5 found that patients with acute myocardial infarction complicated by hemodynamically unstable bradyarrhythmia had a higher response rate to atropine therapy compared to patients without acute myocardial infarction.

Considerations for Post-Surgical Patients with Bradycardia

• Post-surgical patients with bradycardia should be closely monitored for signs of hemodynamic instability, such as hypotension, ischemic chest pain, and decreased cardiac output.
• The treatment of bradycardia in post-surgical patients should be individualized based on the underlying cause and the patient's clinical condition.
• Transesophageal atrial pacing and atropine are effective treatments for bradycardia in post-surgical patients, but the choice of treatment should be based on the patient's specific needs and medical history 2, 4, 5.