Inappropriate sinus tachycardia after radiofrequency ablation of para-Hisian accessory pathways.

Abstract

INTRODUCTION: Inappropriate sinus tachycardia (IST) has been observed following radiofrequency ablation (RFA) of the AV nodal fast pathway. This study was aimed to prospectively analyze the incidence and clinical significance of IST following RFA of para-Hisian accessory pathways (APs). METHODS AND RESULTS: Twenty-eight patients (pts) with para-Hisian APs underwent RFA. An AP was defined as para-Hisian whenever its atrial and ventricular insertions were associated with a His-bundle potential > or = 0.1 mV. RF current was always delivered at the atrial aspect of the tricuspid annulus, to a site where the His-bundle potential was < 0.15 mV. Time- and frequency-domain analysis of heart rate variability was performed in 22 patients, before and after RFA. Abolition of AP conduction was obtained in all pts, and no AV conduction alteration occurred. Six pts (21.4%) presented with IST 45 to 240 minutes after the ablation procedure. In 5 of them, IST disappeared spontaneously within 72 hours, whereas in 1 pt beta-blockers were required for 2 months. The atrial potential amplitude (1.217 +/- 0.264 mV vs 0.882 +/- 0.173 mV, P = 0.009) and A/V potential amplitude ratio (2.633 vs 1.686, P = 0.05) were significantly higher in pts who developed IST than in those who did not. A marked decrease in heart rate variability was observed only in pts who developed IST. CONCLUSION: IST is a relatively frequent complication after RFA of para-Hisian APs: it is generally short-lasting and usually does not require any treatment. IST after catheter ablation is likely to depend upon transient parasympathetic denervation of the sinus node.

AI evidence extraction

Main findings

Among 28 patients undergoing radiofrequency ablation of para-Hisian accessory pathways, 6 (21.4%) developed inappropriate sinus tachycardia 45–240 minutes after the procedure. IST resolved spontaneously within 72 hours in 5 patients; 1 required beta-blockers for 2 months. A marked decrease in heart rate variability was observed only in patients who developed IST, and atrial potential amplitude and A/V ratio at the ablation site were higher in those who developed IST.

Outcomes measured

• Incidence of inappropriate sinus tachycardia (IST) after ablation
• Heart rate variability (time- and frequency-domain) before vs after ablation
• Need for treatment and duration of IST
• Procedural success (abolition of accessory pathway conduction)
• AV conduction alteration

Limitations

• Prospective analysis mentioned but study design details (e.g., control group, randomization) not provided in abstract
• Heart rate variability analysis performed in 22/28 patients (incomplete outcome assessment)
• Short follow-up for most IST outcomes (up to 72 hours for spontaneous resolution; one patient treated for 2 months)
• Mechanistic explanation (parasympathetic denervation) is presented as likely but not directly demonstrated

{
    "study_type": "cohort",
    "exposure": {
        "band": null,
        "source": "radiofrequency ablation (catheter)",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Patients with para-Hisian accessory pathways undergoing radiofrequency ablation",
    "sample_size": 28,
    "outcomes": [
        "Incidence of inappropriate sinus tachycardia (IST) after ablation",
        "Heart rate variability (time- and frequency-domain) before vs after ablation",
        "Need for treatment and duration of IST",
        "Procedural success (abolition of accessory pathway conduction)",
        "AV conduction alteration"
    ],
    "main_findings": "Among 28 patients undergoing radiofrequency ablation of para-Hisian accessory pathways, 6 (21.4%) developed inappropriate sinus tachycardia 45–240 minutes after the procedure. IST resolved spontaneously within 72 hours in 5 patients; 1 required beta-blockers for 2 months. A marked decrease in heart rate variability was observed only in patients who developed IST, and atrial potential amplitude and A/V ratio at the ablation site were higher in those who developed IST.",
    "effect_direction": "harm",
    "limitations": [
        "Prospective analysis mentioned but study design details (e.g., control group, randomization) not provided in abstract",
        "Heart rate variability analysis performed in 22/28 patients (incomplete outcome assessment)",
        "Short follow-up for most IST outcomes (up to 72 hours for spontaneous resolution; one patient treated for 2 months)",
        "Mechanistic explanation (parasympathetic denervation) is presented as likely but not directly demonstrated"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "inappropriate sinus tachycardia",
        "radiofrequency ablation",
        "para-Hisian accessory pathway",
        "His bundle potential",
        "heart rate variability",
        "parasympathetic denervation",
        "catheter ablation complication"
    ],
    "suggested_hubs": []
}

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