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72 year old male with dual chamber implanted for symptomatic sick sinus syndrome (tachy-brady syndrome).
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Currently programmed VVIR 60-130 (persistent AF)
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55% ventricular paced with underlying slow AF
Stable trend on quick look screen
impedance: 466 ohms
sensing: 15mV
threshold: 0.75V @0.4ms
413 VHR episodes
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Ventricular rate >400 (non-physiological)
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Internal lead issues
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Fracture noise
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insulation breach
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header connection issues
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Internal - pt factors -
TWOs
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Double R wave counting
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P wave oversensing
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Myopotential
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External factors
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EMI
Getting the patient to perform arm maneuvers may reproduce/evoke lead noise
Manipulation of the header may also illicit lead noise
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Noise with oversensing
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effecting ventricular capture
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Implications/Risks
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oversensing resorting in pacing inhibition​
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intermittent loss of capture
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Short term programming options
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Increase sensitivity to avoid excessive oversensing (not appropriate in ICD)
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Check is noise is in bipolar and/or in unipolar (if no noise seen in unipolar - this configuration may be a useful bridging fix)
Ultimately
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Patient needs a new lead
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More urgent if patient is dependent
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The start of a lead failure does not always come with abnormal lead trends
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However, in this example, although the lead trends looked completely normal on the quick look screen, once the trend was looked into with more detail, abnormal variations were clearly evident.
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This lead trend is consistent with a partial insulation breach
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