In a post CABG patient with atrial fibrillation and a ventricular rate in the 40s, which pacing mode is appropriate to increase heart rate?

In a post-CABG patient with atrial fibrillation and a ventricular rate in the 40s, the most appropriate pacing mode to increase heart rate is VVI.

This mode stands for Ventricular Inhibition and is used primarily when there is an indication to pace the ventricle while allowing the atrium to function autonomously. Since the patient has atrial fibrillation, the atrial impulses are erratic and ineffective in stimulating the ventricles properly. By using VVI pacing, the pacemaker can provide ventricular pacing at a set rate, ensuring that the ventricles are activated effectively to increase the heart rate. This becomes especially beneficial in a scenario where intrinsic ventricular activity is insufficient due to low heart rate.

With VVI pacing, the pacemaker checks for intrinsic ventricular activity and will output pacing stimulus only when it fails to sense a ventricular beat within a predetermined time. This mode is well-suited for managing bradycardia and a slow ventricular rate provoked by the atrial fibrillation in this specific post-surgical context.

Other pacing modes, such as DDD, DVI, or AAI, either may not effectively address the bradycardia seen in this scenario, or they are less suitable for pacing during