Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
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Comparative Study
Electrophysiological and anatomical differences of the slow pathway between the fast-slow form and slow-slow form of atrioventricular nodal reentrant tachycardia.
This study aimed to clarify whether electrophysiological and anatomical properties of the slow pathway (SP) could be different between the fast-slow form (F/S) and the slow-slow form (S/S) atrioventricular nodal reentrant tachycardia (AVNRT). ⋯ Properties of the retrograde SP differ between F/S and S/S of AVNRT. Fast-slow form may utilize the same pathway for the retrograde conduction as the anterograde SP in S/S.
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Comparative Study
The effect of radiotherapy beam energy on modern cardiac devices: an in vitro study.
Radiotherapy (RT) for malignancies can harm pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). There is some evidence that, besides cumulative dose, the damaging radiation effects increase with beam energy. The aim of this study was to determine whether modern PMs and ICDs are more sensitive to high-energy than to low-energy photon beams. ⋯ Photon beam energy plays a considerable role in inducing implantable cardiac device malfunctions. Low-energy RT may be safer in PM/ICD patients despite relatively high radiation dose to the device.
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Multicenter Study
Long-term follow-up of asymptomatic Brugada patients with inducible ventricular fibrillation under hydroquinidine.
To evaluate the long-term efficacy and safety of an electrophysiologically guided therapy, based on a strategy of treatment using hydroquinidine (HQ) among asymptomatic Brugada patients with inducible ventricular fibrillation (VF). ⋯ Our long-term follow-up results emphasize that the rate of arrhythmic events among asymptomatic Brugada patients with inducible VF remains low over time. Our results also suggest that residual inducibility under HQ is of limited value to predict events during follow-up.
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In patients with pacemakers, hyperkalaemia causes three important abnormalities that usually become manifest when the K level exceeds 7 mEq/L: (i) widening of the paced QRS complex from delayed intraventricular conduction velocity, (ii) Increased atrial and ventricular pacing thresholds that may cause failure to capture. In this respect, the atria are more susceptible to loss of capture than the ventricles, and (iii) Increased latency (usually with ventricular pacing) manifested by a greater delay of the interval from the pacemaker stimulus to the onset of depolarization. First-degree ventricular pacemaker exit block may progress to second-degree Wenckebach (type I) exit block characterized by gradual prolongation of the interval from the pacemaker stimulus to the onset of the paced QRS complex ultimately resulting in an ineffectual stimulus. ⋯ With implantable cardioverter-defibrillators (ICDs) oversensing of the paced or spontaneous T-wave may occur. The latter may cause inappropriate shocks. A raised impedance from the right ventricular coil to the superior vena cava coil may become an important sign of hyperkalaemia in the asymptomatic or the minimally symptomatic ICD patient.
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Absent left atrium (LA) mechanical contraction may occur following the modified Cox-maze operation, and was found to impose a potential risk for the occurrence of thrombo-embolic stroke. It is unknown whether certain morphological P-wave characteristics can surrogate absent LA mechanical activity. The aim of this study was to evaluate the morphological features of the P-waves on the surface electrocardiogram (ECG) of patients who underwent the maze operation and to relate them to the contractile profile of the LA. ⋯ Absent LA mechanical contraction following the modified maze operation may be accompanied by a distinguished pattern of the P-waves on the surface ECG.