Mechanism of ventricular rate control after radiofrequency modification of atrioventricular conduction in patients with atrial fibrillation.

Circulation · 1996 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 4219

Study snapshot

PublicationCirculation · 1996

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

BACKGROUND: Modification of atrioventricular (AV) conduction during atrial fibrillation (AF) may be achieved by radiofrequency ablation in the posteroseptal region of the tricuspid annulus. We tested the hypothesis that elimination of the posterior atrionodal input rather than direct damage to the compact AV node accounts for the decrease in ventricular rate after AV nodal modification. METHODS AND RESULTS: Twenty-four patients with the typical form of AV nodal reentrant tachycardia (AVNRT) underwent selective radiofrequency ablation of the slow AV nodal pathway in the posteroseptal tricuspid annulus. AF was induced before ablation (phase 1), 30 minutes after ablation (phase 2), and during follow-up 24 hours after ablation (phase 3), both with and without concurrent infusion of isoproterenol (4 micrograms/min). Successful elimination of AVNRT was achieved in all patients. During phase 3, 11 patients (46%) had residual dual pathway physiology. AV nodal Wenckebach cycle length (AVNW-CL) increased progressively during each phase of the protocol (356 +/- 72 versus 371 +/- 78 ms versus 432 +/- 104 ms, P < .0001), as did the effective refractory period of the AV node (279 +/- 60 versus 304 +/- 67 ms versus 372 +/- 56 ms, P < .0001). Minimal, mean, and maximal RR intervals during AF progressively increased immediately after ablation and 24 hours later (485 +/- 88 versus 533 +/- 116 ms versus 637 +/- 142 ms for mean RR, P < .0001). The changes in AVNW-CL, AV nodal effective refractory period, and ventricular response during AF were independent of residual dual pathway physiology after ablation. Similar observations were observed during isoproterenol infusion. CONCLUSIONS: Modification of AV nodal conduction during AF by radiofrequency ablation in the posteroseptal tricuspid annulus is independent of the presence or absence of a residual slow AV nodal pathway. On the basis of these observations, the mechanism of AV nodal modification is consistent with elimination of the posterior atrionodal input.

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Study typeother

Effect directionunclear

PopulationPatients with typical AV nodal reentrant tachycardia (AVNRT); atrial fibrillation (AF) induced during protocol

Sample size24

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

In 24 patients undergoing selective radiofrequency ablation of the slow AV nodal pathway, AVNW-CL and AV nodal effective refractory period increased progressively across phases (before ablation, 30 minutes after, and 24 hours after). Mean RR interval during induced AF increased after ablation and at 24 hours. Changes were reported as independent of residual dual pathway physiology, with similar observations during isoproterenol infusion.

Outcomes measured

AV nodal Wenckebach cycle length (AVNW-CL)
AV nodal effective refractory period
Minimal/mean/maximal RR intervals during induced AF
Residual dual pathway physiology after ablation
Elimination of AVNRT

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "radiofrequency ablation (medical procedure)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Patients with typical AV nodal reentrant tachycardia (AVNRT); atrial fibrillation (AF) induced during protocol",
  "sample_size": 24,
  "outcomes": [
    "AV nodal Wenckebach cycle length (AVNW-CL)",
    "AV nodal effective refractory period",
    "Minimal/mean/maximal RR intervals during induced AF",
    "Residual dual pathway physiology after ablation",
    "Elimination of AVNRT"
  ],
  "main_findings": "In 24 patients undergoing selective radiofrequency ablation of the slow AV nodal pathway, AVNW-CL and AV nodal effective refractory period increased progressively across phases (before ablation, 30 minutes after, and 24 hours after). Mean RR interval during induced AF increased after ablation and at 24 hours. Changes were reported as independent of residual dual pathway physiology, with similar observations during isoproterenol infusion.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "radiofrequency ablation",
    "atrioventricular node",
    "AV nodal modification",
    "atrial fibrillation",
    "AVNRT",
    "slow pathway",
    "ventricular rate control",
    "isoproterenol"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1161/01.cir.94.11.2856
PubMed: 8941113

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