Intricate heart with multiple electrical pathways converging.

PVCs and Intramural Origins: A New Hope for Heart Rhythm

Q: What are ventricular arrhythmias and what are some of their origins?

Ventricular arrhythmias, including ventricular tachycardia (VT) and premature ventricular contractions (PVCs), originate in the ventricles. Idiopathic ventricular arrhythmias occur in individuals without structural heart disease. While many originate from the right ventricular outflow tract (RVOT), some arise from the left ventricular outflow tract (LVOT) or papillary muscles. These variations present different challenges during diagnosis and treatment.

Q: How effective is multi-site ablation for treating ventricular arrhythmias originating from deep within the heart muscle?

The study involved performing sequential ablation on multiple early activation sites, achieving arrhythmia suppression in 93% of patients. Electroanatomical mapping (EAM) was used to locate the origins of the arrhythmias; sometimes manually and sometimes utilizing a magnetic robotic system (Stereotaxis). Follow-up over approximately 21.5 months showed patients with successful multi-site ablation remained free from clinical ventricular arrhythmias. This highlights the importance of a comprehensive strategy targeting multiple sites, especially when none of the early sites is greater than -30 ms pre-QRS.

Q: Why are intramural LVOT ventricular arrhythmias so difficult to treat with traditional methods?

Intramural LVOT ventricular arrhythmias present a challenge because their origin is deep within the heart muscle, and they can arise from various anatomical structures, such as the subaortic region, coronary cusps, the aortic-mitral continuity (AMC), the coronary venous system, and the left ventricular summit. Traditional ablation methods may be less effective due to this depth, often requiring multiple procedures with suboptimal results. This is why targeting multiple early activation sites can improve outcomes.

Q: Where are the most common locations for arrhythmia to originate in intramural LVOT ventricular arrhythmias, and how are these locations identified?

Activation mapping identified the most common sites as coronary cusps (86.7%), AMC (86.7%), and the LV summit (80%). Identifying these common locations during electroanatomical mapping is crucial for successful ablation. The study also found that patients with multiple early activation sites often presented with shorter pre-QRS activation times compared to those with a single early activation site (-26 ± 3 msec vs -38 ± 6 msec, p < 0.005), which helps in identifying patients who would benefit from multi-site ablation.

Q: What are the implications of this research for the future of treating ventricular arrhythmias?

This research advances the approach to treating ventricular arrhythmias, mainly those with intramural origins, by mapping and ablating multiple activation sites. This offers a more effective strategy for achieving both acute and long-term arrhythmia suppression. It emphasizes personalized and precise treatment methods, considering the location and timing of multiple activation sites. Future research will likely focus on refining mapping techniques and ablation strategies to improve outcomes further and reduce the need for repeat procedures.

Lena Voss in Health & Wellness September 2025 • 4 min read.

"Variant Ventricular Arrhythmias: How Multi-Site Ablation Changes the Game."

Ventricular arrhythmias (VAs), including ventricular tachycardia (VT) and premature ventricular contractions (PVCs), are heart rhythm disturbances that originate in the ventricles. When these arrhythmias occur in individuals without underlying structural heart disease, they are termed idiopathic ventricular arrhythmias. While many originate from the right ventricular outflow tract (RVOT), some arise from the left ventricular outflow tract (LVOT) or papillary muscles, presenting unique challenges for treatment.

Pinpointing the exact origin of LVOT VAs can be difficult because they can arise from various anatomical structures such as the subaortic region, coronary cusps, the aortic-mitral continuity, the coronary venous system, and the left ventricular summit. Traditional ablation methods, which aim to eliminate the arrhythmia's source, may be less effective when the origin is deep within the heart muscle (intramural), often requiring multiple procedures and yielding suboptimal results.

New research offers a promising approach for patients with intramural LVOT VAs. This article will delve into a study that investigates the benefits of sequential ablation of multiple early activation sites. By targeting several locations where the arrhythmia initiates, this technique aims to improve both acute and long-term outcomes for individuals with these challenging heart rhythm conditions.

Why Targeting Multiple Sites Matters in Intramural PVCs

Intricate heart with multiple electrical pathways converging.

A study was conducted involving 116 patients undergoing ablation for symptomatic LVOT VAs. Of these, 15 patients (13%) were identified as having multiple sites of early activation. These patients often presented with unique characteristics; including shorter pre-QRS activation times compared to those with a single early activation site (-26 ± 3 msec vs -38 ± 6 msec, p < 0.005).

The study employed a detailed electroanatomical mapping (EAM) to locate the precise origins of the arrhythmias. In 86 cases, mapping was performed manually, while the remaining cases utilized a magnetic robotic system (Stereotaxis). During the procedure, activation mapping identified areas of early electrical activity, confirmed by unipolar QS electrograms.

Sequential Ablation: The research team performed sequential ablation on multiple early activation sites, achieving arrhythmia suppression in 93% of patients.
Long-Term Success: Over a follow-up period of approximately 21.5 months, patients who underwent successful multi-site ablation remained free from clinical VAs.
Location Matters: Activation mapping pinpointed the most common sites as coronary cusps (86.7%), AMC (86.7%), and the LV summit (80%).

These findings suggest that intramural LVOT VAs often require a more comprehensive ablation strategy, targeting multiple sites to achieve lasting success. Moreover, the study highlights that if none of the early sites is greater than -30 ms pre-QRS, targeting each one individually is essential.

The Future of PVC Ablation: Personalized and Precise

This research indicates a significant advancement in treating ventricular arrhythmias, particularly those with intramural origins. The approach of mapping and ablating multiple activation sites offers a more effective strategy for achieving both acute and long-term arrhythmia suppression.

While the study acknowledges limitations such as small sample size and the specialized expertise required, the findings underscore the importance of personalized treatment strategies based on detailed electrophysiological mapping. As technology advances, more precise and less invasive ablation techniques are likely to emerge, further improving outcomes for patients with VAs.

For individuals experiencing frequent or symptomatic PVCs, consulting with a cardiologist or electrophysiologist is crucial to determine the most appropriate diagnostic and treatment options. This research offers hope for those who have not found relief through traditional ablation methods.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.hrthm.2018.11.028, Alternate LINK

Title: Variant Of Ventricular Outflow Tract Ventricular Arrhythmias Requiring Ablation From Multiple Sites: Intramural Origin

Subject: Physiology (medical)

Journal: Heart Rhythm

Publisher: Elsevier BV

Authors: Luigi Di Biase, Jorge Romero, Erica S. Zado, Juan Carlos Diaz, Carola Gianni, Patrick M. Hranitzki, Javier E. Sanchez, Sanghamitra Mohanty, Amin Al-Ahmad, Prasant Mohanty, Chintan Trivedi, Domenico Della Rocca, Pasquale Santangeli, J. David Burkhardt, Fermin C. Garcia, Francis E. Marchlinski, Andrea Natale

Published: 2019-05-01

Everything You Need To Know

What are ventricular arrhythmias and what are some of their origins?

Ventricular arrhythmias, including ventricular tachycardia (VT) and premature ventricular contractions (PVCs), originate in the ventricles. Idiopathic ventricular arrhythmias occur in individuals without structural heart disease. While many originate from the right ventricular outflow tract (RVOT), some arise from the left ventricular outflow tract (LVOT) or papillary muscles. These variations present different challenges during diagnosis and treatment.

How effective is multi-site ablation for treating ventricular arrhythmias originating from deep within the heart muscle?

The study involved performing sequential ablation on multiple early activation sites, achieving arrhythmia suppression in 93% of patients. Electroanatomical mapping (EAM) was used to locate the origins of the arrhythmias; sometimes manually and sometimes utilizing a magnetic robotic system (Stereotaxis). Follow-up over approximately 21.5 months showed patients with successful multi-site ablation remained free from clinical ventricular arrhythmias. This highlights the importance of a comprehensive strategy targeting multiple sites, especially when none of the early sites is greater than -30 ms pre-QRS.

Why are intramural LVOT ventricular arrhythmias so difficult to treat with traditional methods?

Intramural LVOT ventricular arrhythmias present a challenge because their origin is deep within the heart muscle, and they can arise from various anatomical structures, such as the subaortic region, coronary cusps, the aortic-mitral continuity (AMC), the coronary venous system, and the left ventricular summit. Traditional ablation methods may be less effective due to this depth, often requiring multiple procedures with suboptimal results. This is why targeting multiple early activation sites can improve outcomes.

Where are the most common locations for arrhythmia to originate in intramural LVOT ventricular arrhythmias, and how are these locations identified?

Activation mapping identified the most common sites as coronary cusps (86.7%), AMC (86.7%), and the LV summit (80%). Identifying these common locations during electroanatomical mapping is crucial for successful ablation. The study also found that patients with multiple early activation sites often presented with shorter pre-QRS activation times compared to those with a single early activation site (-26 ± 3 msec vs -38 ± 6 msec, p < 0.005), which helps in identifying patients who would benefit from multi-site ablation.

What are the implications of this research for the future of treating ventricular arrhythmias?

This research advances the approach to treating ventricular arrhythmias, mainly those with intramural origins, by mapping and ablating multiple activation sites. This offers a more effective strategy for achieving both acute and long-term arrhythmia suppression. It emphasizes personalized and precise treatment methods, considering the location and timing of multiple activation sites. Future research will likely focus on refining mapping techniques and ablation strategies to improve outcomes further and reduce the need for repeat procedures.