Heart rhythm : the official journal of the Heart Rhythm Society
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Randomized Controlled Trial Multicenter Study
Randomized trial of pacemaker and lead system for safe scanning at 1.5 Tesla.
Magnetic resonance imaging (MRI) of pacemakers is a relative contraindication because of the risks to the patient from potentially hazardous interactions between the MRI and the pacemaker system. Chest scans (ie, cardiac magnetic resonance scans) are of particular importance and higher risk. The previously Food and Drug Administration-approved magnetic resonance conditional system includes positioning restrictions, limiting the powerful utility of MRI. ⋯ This randomized trial demonstrates that the Advisa MRI pulse generator and CapSureFix MRI 5086MRI lead system is safe and effective in the 1.5 T MRI environment without positioning restrictions for MRI scans or limitations of body parts scanned.
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Patients treated by atrial redirection surgery (Senning or Mustard procedure) for transposition of the great arteries (TGA) have an important risk for heart failure caused by dysfunction of the systemic right ventricle. Conventional nonsystemic ventricular pacing (non-systVP) may even further increase this risk. ⋯ In a population of patients with SenningMustardTGA, acute hemodynamic effects of endocardial systVP and BiVP were significantly and equally better than those of non-systVP. In some patients, systVP and BiVP might even be better than ventricular activation by the intrinsic conduction system.
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Multicenter Study Comparative Study
The prognostic value of early repolarization (J wave) and ST-segment morphology after J wave in Brugada syndrome: multicenter study in Japan.
The prognostic value of a J wave and ST-segment morphology after J wave in inferolateral leads in Brugada syndrome (BS) is still unknown. ⋯ The presence of a J wave in multiple leads and horizontal ST-segment morphology after J wave may indicate a highly arrhythmogenic substrate in patients with BS.
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Comparative Study
Sympathetic nerve fibers and ganglia in canine cervical vagus nerves: localization and quantitation.
Cervical vagal nerve (CVN) stimulation may improve left ventricular ejection fraction in patients with heart failure. ⋯ Sympathetic nerve fibers are invariably present in the CVNs of normal dogs and occupy in average up to 2.8% of the cross-sectional area. Because sympathetic nerve fibers are present in the periphery of the CVNs, they may be susceptible to activation by electrical stimulation. Spontaneous activation of the sympathetic component of the vagal nerve may accelerate the heart rate.
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Conventional therapy with beta-blockers is incompletely effective in preventing arrhythmic events in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT). We have previously discovered that flecainide in addition to conventional drug therapy prevents ventricular arrhythmias in patients with genotype-positive CPVT. ⋯ Flecainide was effective in patients with genotype-negative CPVT, suggesting that spontaneous Ca(2+) release from ryanodine channels plays a role in arrhythmia susceptibility, similar to that in patients with genotype-positive CPVT.