PVCs arising from Inferoapical Left Ventricle

 

Watch the above video for ECG example explained.

Premature Ventricular Complexes (PVCs) Arising from the Inferoapical Left Ventricle

Premature ventricular complexes (PVCs) originating from the inferoapical left ventricle (LV) represent a less common subset of idiopathic ventricular ectopy. Unlike the more frequent right ventricular outflow tract (RVOT) PVCs, inferoapical LV PVCs arise from the distal inferior wall or apical segments of the LV and have distinct electrocardiographic and mapping characteristics.

Recognition of their ECG pattern is essential for:

Accurate localization

Differentiation from fascicular or papillary muscle PVCs

Planning catheter ablation

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Anatomical Substrate

The inferoapical LV corresponds to:

Distal inferior wall

True apex (inferior portion)

Region supplied mainly by the posterior descending artery (RCA or LCx depending on dominance)

Potential arrhythmogenic substrates:

Idiopathic focal automaticity

Triggered activity

Small areas of fibrosis (post-myocarditis or subclinical ischemia)

Post-infarct scar (if structural disease present)

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ECG Characteristics

Localization relies heavily on 12-lead ECG morphology.

1. Bundle Branch Pattern

Most inferoapical LV PVCs demonstrate:

Right bundle branch block (RBBB) morphology

Because activation spreads from LV to RV

Dominant R wave in V1

This differentiates them from RVOT PVCs (which show LBBB pattern).

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2. Frontal Plane Axis

Axis depends on exact origin:

Superior axis (negative QRS in inferior leads)

→ Suggests origin from inferior LV wall

May show:

Negative QRS in II, III, aVF

Positive in I and aVL

If origin is more apical-inferior:

Inferior leads often deeply negative

Marked superior axis deviation

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3. Precordial Transition

Late precordial transition (after V4–V5)

Dominant S waves in early precordial leads

Broad QRS (>140 ms typical in LV origin)

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Typical ECG Summary Pattern

Inferoapical LV PVC:

RBBB morphology

Superior axis

Late transition

Broad QRS

Often monomorphic

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Differentiation from Other LV PVC Sites

1. Fascicular PVCs

Narrower QRS

RBBB + superior axis (posterior fascicle VT)

Often responsive to verapamil

Usually re-entrant rather than purely focal

2. Papillary Muscle PVCs

Variable axis

Multiple morphologies

Often difficult ablation due to mobility

3. LV Outflow Tract PVCs

Inferior axis (positive II, III, aVF)

Early transition

Inferoapical PVCs typically have a superior axis, helping distinction.

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Clinical Presentation

Patients may present with:

Palpitations

Missed beats

Exercise-induced ectopy

High PVC burden (>10–15%) leading to PVC-induced cardiomyopathy

In structurally normal hearts → Often benign

In structural heart disease → Requires detailed evaluation

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Diagnostic Workup

1. 12-Lead ECG

Morphology analysis

Axis determination

QRS width

2. Holter Monitoring

PVC burden

Monomorphic vs polymorphic

Coupling interval

3. Echocardiography

LV function

Regional wall motion abnormality

LV dilation (PVC cardiomyopathy)

4. Cardiac MRI

Indicated if:

Reduced EF

Suspicion of scar

Atypical morphology

Detects:

Inferior wall fibrosis

Apical scar

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Mechanism

Most idiopathic inferoapical PVCs are due to:

Focal automaticity

Triggered activity

Less commonly:

Scar-related reentry

Ischemic substrate

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Management

1. Conservative

Reassurance if asymptomatic

Monitor LV function

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2. Medical Therapy

Beta blockers

Non-dihydropyridine CCB (if focal)

Class IC agents (in structurally normal heart)

Amiodarone (if structural disease)

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3. Catheter Ablation

Indications:

Symptomatic PVCs

PVC burden >10–15%

LV dysfunction suspected due to PVCs

Drug intolerance

Mapping features:

Earliest activation at inferoapical LV

Pace mapping match ≥11/12 leads

Often requires retrograde aortic or transseptal LV access

Success rates:

80–90% in experienced centers

Lower if scar-related

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Prognosis

Excellent in idiopathic cases

Reversible LV dysfunction if PVC-induced cardiomyopathy

Higher risk if associated with structural heart disease

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Key Takeaways

Inferoapical LV PVCs show RBBB morphology + superior axis

Late precordial transition

Broad QRS

Important to distinguish from fascicular VT

Ablation highly effective when symptomatic or high burden

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