Heart rhythm : the official journal of the Heart Rhythm Society
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A prolonged heart rate-corrected QT (QTc) interval is a well-known risk indicator for sudden cardiac death (SCD) and a contraindication for drugs with potentially arrhythmogenic adverse effects. ⋯ Persons with an inconsistently prolonged QTc interval did not have a higher risk of SCD than those with a consistently normal QTc interval. Persons with a consistently prolonged QTc interval did have a higher risk of SCD. Our results suggest that repeated measurements of the QTc interval could enhance risk stratification.
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Multicenter Study Clinical Trial
Clinical safety of the Iforia implantable cardioverter-defibrillator system in patients subjected to thoracic spine and cardiac 1.5-T magnetic resonance imaging scanning conditions.
Implantable cardioverter-defibrillators (ICDs) are generally considered a contraindication to magnetic resonance imaging (MRI). ⋯ These results demonstrate the clinical safety and efficacy of the ProMRI ICD system in patients subjected to thoracic spine and cardiac MRI imaging in 1.5-T scanners.
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Radiation therapy (RT) may pose acute and long-term risks for patients with cardiac implantable electronic devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). However, the frequency of these problems has not been accurately defined. ⋯ Nearly 1% of patients receiving RT in this series has a PM or ICD. However, with a systematic policy of risk assessment and patient management, significant device-related complications are rare.
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Bradycardic agents are of interest for the treatment of ischemic heart disease and heart failure, as heart rate is an important determinant of myocardial oxygen consumption. ⋯ We have shown that HCQ acts as a bradycardic agent in SAN cells, in atrial preparations, and in vivo. HCQ slows the rate of spontaneous action potential firing in the SAN through multichannel inhibition, including that of If.