Changes in Myocardial Perfusion During Chronic Multi Site Biventricular Versus Right Ventricular Apex Pacing in Patients With Normal Left Ventricular Function Undergoing His Bundle Ablation for Drug-refractory Atrial Fibrillation

Changes in Myocardial Perfusion During Chronic Multi Site Biventricular Versus Right Ventricular Apex Pacing in Patients With Normal Left Ventricular Function Undergoing His Bundle Ablation for Drug-refractory Atrial Fibrillation

To determine whether Biventricular pacing in patients undergoing HIS bundle ablation for atrial fibrilation has beneficial effects on myocardial perfusion and left ventricularr ejection fraction.

Inclusion Criteria:

• Normal to nearly normal LVF (EF > 40%)
• Drug-refractory, persistent or permanent atrial fibrillation
• Referred for His ablation

Exclusion Criteria:

• Unwilling or unable to sign the informed consent
• Life expectancy < 1year from non-cardiac causes
• Previous myocardial infarction
• Previous coronary bypass surgery
• Poor left ventricle function (EF< 40%) from any cause
• Symptomatic obstructive coronary artery disease
• Poor ultra sound imaging quality.