Heart rhythm : the official journal of the Heart Rhythm Society
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During magnetic resonance imaging (MRI), cardiac implantable electronic device (CIED) leads can be antennae to focus energy onto myocardium, leading to heating and arrhythmias. Clinical data on thoracic MRI safety for patients with legacy devices are limited. ⋯ Thoracic MRI is relatively safe in an institutional multidisciplinary program. It does not represent greater risk than brain MRI for patients with legacy CIEDs.
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The electrophysiological substrate underlying atrial fibrillation (AF) progression remains difficult to identify. ⋯ Patients with AFr after first ablation exhibit IP more frequently at redo ablation than do patients with OATr. IP correlates with more advanced AFr type, larger LA volumes, and progressive right atrial enlargement. PV reconnection is not associated with AFr. Changes in post-PVI AFI may accurately indicate progression of extra-PV AF-maintaining substrate.
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Multicenter Study
Dynamicity of hypothermia-induced J waves and the mechanism involved.
J waves develop during hypothermia, but the dynamicity of hypothermia-induced J waves is poorly understood. ⋯ J waves in severe hypothermia were augmented after short RR intervals in 7 patients as expected for depolarization abnormality, whereas 2 patients showed a bradycardia-dependent augmentation as expected for transient outward current-mediated J waves. Increased conduction delay at short RR intervals can be responsible for the accentuation of the transient outward current and J waves during severe hypothermia.
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Second-generation cryoballoon (CB2)-based pulmonary vein isolation (PVI) has demonstrated encouraging clinical results for the treatment of paroxysmal atrial fibrillation (AF) and persistent AF. However, rhythm follow-up after PVI is mainly based on Holter electrocardiography of limited duration. ⋯ CB2-PVI seems safe and feasible in patients with an implanted cardiac device. A significantly higher AF/AT burden was seen in patients with an implanted cardiac device compared to a control group.
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The role of cryoballoon ablation (CBA) for antral pulmonary vein isolation (APVI) has not been well established in persistent atrial fibrillation (PerAF). Isolation of the left atrial posterior wall (BOX) after APVI has been suggested to improve the efficacy of radiofrequency catheter ablation (RFA) in PerAF. ⋯ In PerAF, an initial approach of APVI by CBA or APVI + BOX by CF-RFA has a similar efficacy of 40%-50% without AADs. After repeat ablation for APVI + BOX by CF-RFA in ∼25%, sinus rhythm is maintained in 60%-70% of patients without AADs.