What diagnosis does a great sinus vein ablation correct?

Great Cardiac Vein Ablation for Idiopathic Ventricular Arrhythmias

Great cardiac vein ablation corrects idiopathic ventricular arrhythmias (premature ventricular contractions and ventricular tachycardia) originating from the left ventricular outflow tract, specifically those arising from the epicardial LV summit region that cannot be accessed via endocardial approaches. 1

Primary Indication

The great cardiac vein serves as an epicardial access route for ablation of ventricular arrhythmias originating from the LV summit—a region where approximately 10% of idiopathic ventricular arrhythmias arise. 1 These arrhythmias typically present as:

• Premature ventricular contractions (PVCs) with left bundle branch block morphology and inferior axis 2
• Non-sustained or sustained ventricular tachycardia 1
• Exercise-induced or catecholamine-sensitive arrhythmias 1

When Great Cardiac Vein Ablation Is Considered

The great cardiac vein approach is reserved for cases where standard endocardial ablation has failed or is not feasible. 1 The decision algorithm proceeds as follows:

1. Initial endocardial mapping of the left ventricular outflow tract, aortic sinuses, and below the aortic valve 1

2. If earliest activation is identified at the LV summit but the site is inaccessible endocardially due to proximity to the left coronary artery (within 6 mm), consider epicardial approaches 1

3. Great cardiac vein mapping and ablation is attempted before direct epicardial puncture, as it provides safer access to the epicardial LV summit 1

4. Direct epicardial surface ablation via pericardial puncture is reserved for cases where great cardiac vein ablation is unsuccessful 1

Electrophysiological Characteristics

Successful ablation sites in the great cardiac vein demonstrate:

• Earliest ventricular activation preceding QRS onset by ≥25-42 ms 2
• Pace mapping showing ≥11/12 lead match with clinical PVC morphology 1
• Two distinct QRS morphologies (left bundle branch block and right bundle branch block patterns) may originate from the same great cardiac vein site due to preferential conduction patterns 2

Technical Success and Safety Profile

Catheter ablation via the great cardiac vein achieves >90% acute success rates for accessible LV summit arrhythmias in experienced centers. 1 However, critical limitations exist:

• Some LV summit origins remain inaccessible even via the great cardiac vein due to anatomical constraints or excessive distance from the vein 1
• Proximity to coronary arteries (particularly the left anterior descending) requires angiographic confirmation of ≥6 mm safety margin before energy delivery 1
• Intramural origins may require combined endocardial and epicardial ablation 1

Common Pitfalls to Avoid

Do not attempt great cardiac vein ablation without coronary angiography to map the left anterior descending and circumflex arteries, as thermal injury to these vessels is a major complication. 1 The great cardiac vein runs in close proximity to these structures along the anterior interventricular groove.

Recognize that overlying epicardial fat pads can impede effective energy delivery even when the catheter is optimally positioned in the great cardiac vein. 1

Understand that failure to eliminate arrhythmias from the great cardiac vein does not indicate procedural failure—it may indicate an intramural or deeper epicardial origin requiring alternative approaches. 1

Patient Selection Criteria

Great cardiac vein ablation should be offered to patients with:

• Symptomatic ventricular arrhythmias causing palpitations, presyncope, or reduced quality of life 1
• High PVC burden (typically >10,000-20,000 PVCs per 24 hours) with risk of PVC-induced cardiomyopathy 1
• Failed antiarrhythmic therapy (beta-blockers, calcium channel blockers, or class IC agents) or medication intolerance 1
• Mapping data confirming LV summit origin with earliest activation in the great cardiac vein region 1, 2