Impact of Catheter Ablation of Frequent Premature Ventricular Complexes in Treating Subtle Left Cardiomyopathy

Efficacy of Catheter Ablation of Frequent Asymptomatic Idiopathic Premature Ventricular Complexes in Treating Latent Left Ventricular Systolic Dysfunction As Being Assessed by Speckle Tracking of LV Global Longitudinal Strain

Throughout the past decade, there were no straightforward recommendations regarding the management of asymptomatic high-burden Premature ventricular complexes (PVCs) in structurally normal heart extending from the European Society of Cardiology (ESC) guidelines of management of ventricular arrhythmias in 2014, passing by the American Heart Association (AHA), American College of Cardiology (ACC), and Heart Rhythm Association (HRA) guidelines 2017, and reaching to the recent ESC guidelines in 2022 that declared overtly that there is a gap of evidence regarding management of asymptomatic high burden PVCs in structurally normal heart.

The goal of this clinical trial is to know if other imaging modalities rather than the conventional Two-dimension (2D) echocardiography can guide the treatment strategy of high-burden idiopathic premature ventricular complexes (PVCs). In our clinical trial, we used 2D speckle tracking of left ventricular (LV) global longitudinal strain (GLS) as an indicator for subtle LV systolic dysfunction in patients with structurally normal heart by conventional echocardiography.

The main questions the trial aims to answer are:

• Is radiofrequency catheter ablation an effective method in the treatment of early subtle myocardial dysfunction in patients with normal left ventricle ejection fraction (LVEF) and internal dimensions guided by 2D STE of GLS before progression into overt LV systolic dysfunction?
• Is there a correlation between radiofrequency catheter ablation of asymptomatic frequent idiopathic PVCs and improvement of patient functional capacity as an indicator for subconscious adaptation?
• Is there a correlation between PVC burden and the degree of impairment of GLS?

Researchers will compare group A (control group) and group B (ablation group) to see if there is a significant difference between them regarding global longitudinal strain.

Participants will be randomized into two groups each containing 20 patients. Group A (Control group): will be subjected to the standard of care being regular follow-up of symptom status and left ventricular ejection fraction (LVEF) Group B (ablation group): will be scheduled for PVC ablation.

The clinical trial was conducted from June 2023 to August 2024. A total of 218 patients entered the screening phase. Of that participant pool, 116 patients did not fulfill the eligibility criteria since 90 patients were symptomatic, 33 patients had more than one PVC morphology in Holter ECG monitoring, 10 patients had episodes of atrial fibrillation (AF) in Holter ECG monitoring, 2 patients were diagnosed with chronic obstructive pulmonary disease (COPD), 1 patient had chronic kidney disease (CKD).

The other 100 patients continued with the subsequent stage of assessment of LV GLS, as mentioned in the outlined methodology. Of this cohort, 60 patients were excluded from the study because they did not meet the criteria for randomization, as they showed normal LV GLS ≥ -16%.

Accordingly, our study was conducted on 40 patients meeting the inclusion criteria mentioned. Those patients were further randomized into two groups each containing 20 patients.

Group A (Control group): subjected to the standard of care being regular follow-up of symptom status and left ventricular ejection fraction (LVEF) Group B (ablation group): scheduled for PVC ablation.

After a minimum duration of 3 months all participants were applied to follow-up assessment of symptoms status, 6-minute walk test (6MWT), PVC burden by Holter ECG monitoring, LV GLS by speckle tracking Echocardiography (STE).

Inclusion Criteria:

• Asymptomatic patients with frequent idiopathic PVCs, defined as PVCs burden of ≥ 20% of total beats in Holter ECG monitoring in the structurally normal heart as being assessed by conventional 2D echocardiography and normal 12 lead surface ECG.
• Impaired LV GLS by 2D speckle tracking (GLS > -16 %).
• Patients willing and capable of providing informed consent

Exclusion Criteria:

• Multiple co-morbidities that may be potential factors affecting functional capacity including anemia, Chronic obstructive pulmonary disease (COPD), interstitial pulmonary fibrosis, bronchial asthma, Cerebrovascular stroke (CVS), skeletomuscular abnormalities or chronic kidney disease (CKD).
• Symptoms including but not limited to fatigue, palpitations, dyspnea, chest pain, dizziness, syncope, presyncope, or functional limitation that was defined as less than the lower limit of predicted 6-minute walk distance (6 MWD).
• Any electrolyte abnormalities, abnormal arterial blood gases, and/or abnormal thyroid profile.
• Ischemic heart disease (ISHD), in our study ISHD was defined as patients with a previous history of Myocardial infarction, acute coronary syndrome, previous revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG), or objective evidence of myocardial ischemia including noninvasive functional assessment or coronary angiography showing significant stenosis > 50%.
• Symptomatic or asymptomatic structural heart disease including any congenital heart diseases, significant valvular lesion defined as primary or secondary valvular lesion causing abnormal loading condition, or more than grade I diastolic dysfunction.
• Any symptomatic or asymptomatic phenotype of cardiomyopathies.
• Polymorphic PVCs.
• Atrial fibrillation.
• Positive family history of sudden cardiac death.
• Heart failure including heart failure with preserved ejection fraction (HFpEF), heart failure with mildly reduced ejection fraction (HFmrEF), and heart failure with reduced ejection fraction (HFrEF).