What is the management approach for a patient with poor R-wave progression (PRWP) and tachycardia?

Management of Poor R-Wave Progression (PRWP) in Patients with Tachycardia

In patients with poor R-wave progression (PRWP) and tachycardia, the first priority is to identify and treat the underlying tachycardia according to its mechanism, as this will have the greatest impact on morbidity and mortality. 1

Initial Assessment and Diagnosis

• Obtain a 12-lead ECG during tachycardia whenever possible, but do not delay treatment if the patient is hemodynamically unstable 1
• Determine if the QRS is narrow (<120 ms) or wide (≥120 ms) to guide further management 1
• For wide-complex tachycardias, it is critical to differentiate between supraventricular tachycardia (SVT) and ventricular tachycardia (VT) 1
• If diagnosis is uncertain, treat as ventricular tachycardia until proven otherwise 1

Management Algorithm for Tachycardia with PRWP

Step 1: Assess Hemodynamic Stability

• If hemodynamically unstable: Perform immediate synchronized cardioversion 1
• If stable: Proceed with diagnostic and therapeutic measures based on QRS width 1

Step 2: Narrow QRS Complex Tachycardia (<120 ms)

• Try vagal maneuvers and/or IV adenosine as first-line interventions 1
• If ineffective and regular rhythm persists, consider:
  • IV beta-blockers (if no contraindications such as heart failure) 1
  • IV calcium channel blockers (diltiazem or verapamil) if no signs of pre-excitation 1
  • IV amiodarone for patients with heart failure 1

Step 3: Wide QRS Complex Tachycardia (≥120 ms)

• If SVT with aberrancy is suspected:
  • Use adenosine cautiously if the diagnosis is certain 1
  • Avoid verapamil or diltiazem as they may cause hemodynamic collapse if the rhythm is actually VT 1
• If pre-excited AF is suspected (irregular wide-complex tachycardia):
  • Avoid AV nodal blocking agents (digoxin, diltiazem, verapamil, beta-blockers) 1
  • Use procainamide or ibutilide if hemodynamically stable 1
  • Perform immediate cardioversion if unstable 1

Addressing PRWP After Tachycardia Resolution

After controlling the tachycardia, evaluate the PRWP pattern which may be due to:

• Anterior myocardial infarction 2, 3
• Left ventricular hypertrophy 2, 3
• Right ventricular hypertrophy 2, 3
• Normal variant with diminished anterior forces 2, 4

Diagnostic Approach for PRWP:

• Compare ECG during tachycardia with ECG in sinus rhythm 1
• Look for other signs of myocardial infarction (Q waves, ST changes) 2
• Consider echocardiography to evaluate for structural heart disease 2, 3

Special Considerations

• PRWP alone has limited diagnostic value for anterior MI and should not be used as the sole criterion for diagnosis 5
• Tachycardia itself can alter R-wave progression patterns, so reassess after rate control 1
• Technical factors like electrode placement can create false PRWP patterns 4
• For patients with WPW syndrome and tachycardia, consider catheter ablation of the accessory pathway, particularly if they have had syncope or documented AF 1

Pitfalls to Avoid

• Do not administer AV nodal blocking agents (verapamil, diltiazem, beta-blockers) in patients with suspected pre-excitation syndromes as this may accelerate conduction through the accessory pathway and precipitate ventricular fibrillation 1
• Do not delay cardioversion in hemodynamically unstable patients 1
• Do not assume PRWP is always indicative of anterior myocardial infarction, as it has multiple potential causes 2, 5
• Do not initiate antiarrhythmic treatment with class I or class III drugs without a documented arrhythmia due to proarrhythmic risk 1