Two-year clinical follow-up after pulmonary vein isolation using high-intensity focused ultrasound (HIFU) and an esophageal temperature-guided safety algorithm.

Abstract

BACKGROUND AND OBJECTIVE:

High-intensity frequency ultrasound (HIFU) can achieve pulmonary vein isolation (PVI), but severe complications have happened. An esophageal temperature (ET)-guided safety algorithm was implemented. We investigated medium-term outcome.

METHODS:

After left atrial access, HIFU was applied until complete PVI. The safety algorithm was as follows: ≤3 complete ablations per pulmonary vein, early abortion when ET ≥40.0°C, use of Power Modulation at ET >39.0°C or when after 20 to 30 seconds no change in PV electrograms: to reduce the ablation temperature in the surrounding tissue, acoustic power is switched on and off with a frequency of 1 Hz; in all first ablations, use of Power Modulation after 50% of programmed time. Touch-up radiofrequency ablation when PVI failed. Follow-up included interviews and Holter electrocardiograms. Recurrence was defined as atrial fibrillation (AF) >30 seconds without a blanking period.

RESULTS:

A total of 28 symptomatic patients (18 males, age 63 years), with paroxysmal AF (n = 19) and persistent AF (n = 9) were included. After a median follow-up of 738 days, 22 of the 28 patients (79%) were free of AF without antiarrhythmic drugs. After 1 repeat procedure with radiofrequency ablation, 5 patients remained free of AF. The complications were as follows: 1 lethal atrial-to-esophageal fistula at day 31, 1 pericardial effusion at day 48, 1 unexplained death at day 49, and 2 persistent phrenic nerve palsies with full recovery within 12 months.

CONCLUSIONS:

Two-year follow-up after PVI using HIFU and an ET-guided safety algorithm shows success rates similar to those of radiofrequency-based procedures but with higher complication rates. Importantly, the ET-guided safety algorithm failed to prevent severe complications. HIFU does not meet safety standards required for the treatment of AF, and this led to a halt of its clinical use.

• Authors: Kars Neven, Andreas Metzner, Boris Schmidt, Feifan Ouyang, Karl-Heinz Kuck
• Journal: Heart rhythm (Heart Rhythm) Vol. 9 Issue 3 Pg. 407-13 (Mar 2012) ISSN: 1556-3871 [Electronic] United States
• PMID: 21978960 (Publication Type: Journal Article)
• Copyright: Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Chemical References

• Anti-Arrhythmia Agents

Topics

• Algorithms
• Anti-Arrhythmia Agents (therapeutic use)
• Atrial Fibrillation (physiopathology, therapy)
• Catheter Ablation (adverse effects, methods)
• Electrocardiography, Ambulatory
• Equipment Safety
• Esophagus (physiopathology)
• Female
• Follow-Up Studies
• Heart Conduction System (physiopathology, surgery)
• Hot Temperature (adverse effects)
• Humans
• Intraoperative Complications (etiology, prevention & control)
• Male
• Middle Aged
• Monitoring, Physiologic (methods)
• Pulmonary Veins (surgery)
• Pulsed Radiofrequency Treatment (methods)
• Secondary Prevention
• Treatment Outcome
• Ultrasonography, Interventional (adverse effects, methods)