What does a right ventricular conduction delay on an electrocardiogram (EKG) indicate?

Right Ventricular Conduction Delay on EKG

A right ventricular conduction delay on an electrocardiogram indicates a slowing of electrical impulse propagation through the right ventricle, which may be associated with various cardiac conditions including right ventricular hypertrophy, Brugada syndrome, arrhythmogenic right ventricular cardiomyopathy, or right ventricular infarction.

Electrocardiographic Features

Right ventricular conduction delay is characterized by:

• Prolonged QRS duration, particularly in right precordial leads (V1-V3)
• Delayed R-wave peak in right precordial leads
• Possible RSR' pattern (similar to incomplete right bundle branch block)
• Localized QRS prolongation (>110 ms) in leads V1-V3
• QRS duration ratio in (V1+V2+V3)/(V4+V5+V6) ≥ 1.2
• Prolonged S wave upstroke (>55 ms) in leads V1-V3 1

Clinical Significance

The presence of right ventricular conduction delay may indicate:

1. Right Ventricular Hypertrophy (RVH)

• RVH causes displacement of the QRS vector toward the right and anteriorly
• Often causes a delay in the R-wave peak in right precordial leads
• May be associated with right axis deviation
• Can be seen in conditions that impose increased workload on the right ventricle 2

2. Brugada Syndrome

• Right ventricular conduction delay is a key pathophysiological mechanism in Brugada syndrome
• Patients with Brugada syndrome demonstrate longer right ventricular ejection delays
• Male patients with Brugada syndrome show more pronounced delays than females, correlating with their more malignant clinical phenotype 3
• Epsilon-like waves and delayed S wave upstroke in leads V1-V3 may be observed 1

3. Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia (ARVC/D)

• Characterized by progressive increase in delayed ventricular conduction
• Signal-averaged ECG shows increasing late potentials over time
• Conduction disturbances may increase independently from anatomical alterations 4
• Filtered QRS duration in V2 is typically prolonged 5

4. Right Ventricular Infarction or Ischemia

• May present with "cove"-shaped ST-T elevation in lead V1
• This pattern can mask the late r' wave in lead V1 during the hyperacute phase
• Serves as a marker of underlying right ventricular conduction delay 6

Diagnostic Approach

When right ventricular conduction delay is identified:

1. Evaluate for right ventricular hypertrophy using established criteria:

   • Right axis deviation
   • Tall R waves in right precordial leads
   • Deep S waves in left precordial leads 2

2. Look for associated findings:

   • Right atrial abnormality (tall, peaked P waves in lead II >2.5 mm)
   • ST-T abnormalities in right precordial leads
   • Epsilon-like waves in leads V1-V3 1

3. Consider echocardiographic assessment to:

   • Evaluate right ventricular structure and function
   • Assess for underlying structural heart disease
   • Monitor for disease progression

Clinical Implications

The presence of right ventricular conduction delay has important prognostic implications:

• In Brugada syndrome, longer right ventricular ejection delays are associated with previous history of syncope or spontaneous ventricular arrhythmia 3
• In ARVC/D, progressive increase in conduction delay may occur without significant echocardiographic changes 4
• The finding may identify patients at higher risk for ventricular arrhythmias

Pitfalls and Caveats

• Right ventricular conduction delay can be confused with incomplete right bundle branch block
• The sensitivity of ECG criteria for right ventricular hypertrophy is generally low, though specificity can be high 2
• The pattern of conduction delay differs between conditions - in Brugada syndrome, there is dominant prolongation in right precordial leads, while in ARVC/D, the delay is more diffuse 5
• Normal variants can sometimes mimic right ventricular conduction delay, requiring correlation with clinical findings

Right ventricular conduction delay on ECG should prompt a thorough cardiac evaluation to identify the underlying cause and assess for risk of adverse outcomes, particularly arrhythmias.