Prolonged PR interval is a risk factor for bradycardia during spinal anesthesia

Area of Science:

• Cardiology
• Anesthesiology
• Medical Diagnostics

Background:

• Bradycardia complicates 9%-13% of spinal anesthetics, potentially leading to cardiac arrest.
• Preoperative electrocardiogram (ECG) abnormalities as risk factors for bradycardia are not well-established.
• Identifying novel predictors for bradycardia is crucial for patient safety during anesthesia.

Purpose of the Study:

• To investigate the correlation between abnormal findings on preoperative ECGs and the incidence of intraoperative bradycardia.
• To determine if specific ECG abnormalities, such as prolonged PR interval, predict bradycardia during spinal anesthesia.

Main Methods:

• Retrospective analysis of 537 patients undergoing spinal anesthesia with preoperative ECGs.
• Intraoperative bradycardia defined as heart rate < 50 bpm or >10% decrease from baseline.
• ECG abnormalities analyzed included prolonged PR interval, conduction abnormalities, chamber hypertrophy, ischemia, and infarction.

Main Results:

• The overall incidence of bradycardia was 12%.
• Patients with a prolonged PR interval (>0.2 sec) showed a significantly increased incidence of bradycardia (25%, P = .01).
• Logistic regression identified prolonged PR interval as an independent predictor of bradycardia (OR=3.2, P=.01).

Conclusions:

• Prolonged PR interval on preoperative ECG is a significant and independent predictor of bradycardia during spinal anesthesia.
• This finding complements existing risk factors like low heart rate, ASA status, beta-blocker use, and block height.
• Incorporating preoperative ECG findings can enhance risk stratification for bradycardia in patients receiving spinal anesthesia.