Differential Diagnosis for Patient with HR 145, Irregular Rhythm, Narrow QRS, and Visible P-Waves on Lead 2
- Single Most Likely Diagnosis
- Atrial Fibrillation (AFib) with Rapid Ventricular Response: Although the presence of visible P-waves might suggest against AFib, it's possible that the P-waves are buried in the T-waves or that there's a coexisting condition. However, given the irregular rhythm and narrow QRS, AFib remains a strong consideration, especially if the P-waves are not consistently associated with QRS complexes.
- Other Likely Diagnoses
- Atrial Flutter with Variable Block: This condition can present with an irregular rhythm if there's a variable block, and visible P-waves (often in a sawtooth pattern) can be seen, especially in lead II. The narrow QRS suggests a supraventricular origin.
- Multifocal Atrial Tachycardia (MAT): Characterized by an irregular rhythm, narrow QRS complexes, and at least three distinct P-wave morphologies, MAT could fit this presentation, especially if the patient has underlying lung disease.
- Paroxysmal Supraventricular Tachycardia (PSVT) with Variable Block: Although typically regular, if there's a variable block or the patient is transitioning into or out of the tachycardic state, the rhythm could appear irregular.
- Do Not Miss Diagnoses
- Wolff-Parkinson-White (WPW) Syndrome with Atrial Fibrillation: Although the narrow QRS suggests against this, in some cases of WPW, especially if there's a long anterograde refractory period of the accessory pathway, the QRS can remain narrow during AFib. This diagnosis is critical because it can lead to a life-threatening situation if not recognized and managed appropriately.
- Atrial Tachycardia with Block: In the setting of significant cardiac disease or drug effect, an atrial tachycardia can present with a variable block, leading to an irregular rhythm.
- Rare Diagnoses
- Chaotic Atrial Tachycardia: A rare condition characterized by multiple ectopic foci in the atria, leading to an irregular atrial rhythm that can be difficult to distinguish from AFib.
- Junctional Tachycardia with Retrograde P-Waves: Although typically regular, if there's a variable block or the patient has an enhanced atrioventricular (AV) nodal conduction, it could mimic an irregular supraventricular tachycardia with visible P-waves.