In a post CABG patient displaying monomorphic wide QRS tachycardia with dissociated P waves, what is the likely diagnosis?

In the context of a post coronary artery bypass graft (CABG) patient who presents with monomorphic wide QRS tachycardia and dissociated P waves, the diagnosis is likely to be ventricular tachycardia (VT).

Monomorphic wide QRS tachycardia indicates that the QRS complexes are consistent in shape and duration, which is a hallmark of ventricular tachycardia. In this situation, the dissociated P waves suggest that the atria are not conducting normally with the ventricular rhythm, implying that the P waves are originating independently of the QRS complexes. This atrial disassociation is a key feature often associated with VT, where the ventricular activity is more dominant and occurs independently of any atrial activity.

In contrast, sinus tachycardia would typically show a normal QRS configuration and would not present with dissociated P waves, as it reflects a physiological response to factors such as pain or stress. Atrial flutter, while it may have a quick rate, would usually not present with wide QRS unless there is a conduction abnormality, which is less likely given the specificity of the scenario presented. SVT with aberrant conduction could mimic wide QRS complexes but would typically maintain a relationship between the atrial