Contact force-controlled zero-fluoroscopy catheter ablation of right-sided and left atrial arrhythmia substrates.

Background: Conventional catheter ablation of cardiac arrhythmias is associated with radiation risks for patients and laboratory personnel. However, nonfluoroscopic catheter guidance may increase the risk for inadvertent cardiac injury. A novel radiofrequency ablation catheter capable of real-time tissue-tip contact force measurements may compensate for nonfluoroscopic safety issues.

Catheter ablation of persistent atrial fibrillation: anatomically based circumferential pulmonary vein ablation in combination with a potential-guided segmental approach to achieve complete pulmonary vein isolation.

Background: Catheter ablation has become the first line of therapy in patients with symptomatic, recurrent, drug-refractory atrial fibrillation. However, catheter ablation of persistent atrial fibrillation is still a challenge. Various rather complex ablation strategies exist and their results are not very favorable.

Alcohol-induced electrical remodeling: effects of sustained short-term ethanol infusion on ion currents in rabbit atrium.

Background: In some patients, above-average alcohol consumption before occurrence of atrial fibrillation (AF) in terms of a "holiday heart syndrome" (HHS) can be determined. There is evidence that long before development of apparent alcohol-induced cardiomyopathy, above-average alcohol consumption generates an arrhythmogenic substrate which abets the onset of AF. Changes of atrial current densities in terms of an electrical remodeling after sustained short-term ethanol infusion in rabbits as a potential part of HHS pathophysiology were examined in this study.

Inhibition of the renin-angiotensin system: effects on tachycardia-induced early electrical remodelling in rabbit atrium.

Introduction: Tachycardia-induced atrial remodelling (as an equivalent to atrial fibrillation) can be influenced by the renin-angiotensin system. Effects of a seven-day enalapril pre-treatment (EPT, 0.16 mg/kg body weight subcutaneously every 24 h) on ionic currents underlying tachycardia-induced early electrical remodelling after 24 h rapid atrial pacing (RAP, 600 beats/min) in rabbit atrium were studied.

"Home monitoring" for early detection of implantable cardioverter-defibrillator failure: a single-center prospective observational study.

Background: Telemedical ICD monitoring has the potential to enhance patient safety. The "home-monitoring" (HM) feature transmits selected device-related data to a service-center via mobile phone network. In case of a potential emergency situation, event reports are generated automatically.

Patient alert in implantable cardioverter defibrillators: toy or tool?

Objectives: The purpose of this study was to analyze the utility of patient-alert features in implantable cardioverter defibrillators (ICDs).

Background: Various alert features producing acoustic warning signals have been implemented in newer generation ICDs, but their role in early detection of system-related complications has not been systematically evaluated.

Methods: In 240 patients implanted with Medtronic ICD devices, the following alert features were routinely activated: pacing lead impedance <200 or >2,000 Omega, high-voltage lead impedance <10 or >200 Omega, low battery voltage (elective replacement indicator), long charge time (>18 s), >3 shocks delivered per episode, and all therapies in a zone delivered.

Drug binding to aromatic residues in the HERG channel pore cavity as possible explanation for acquired Long QT syndrome by antiparkinsonian drug budipine.

Budipine is a non-dopaminergic antiparkinsonian drug causing acquired forms of Long QT syndrome (aLQTS). As a consequence, the manufacturer has restricted the use of budipine in patients who exhibit additional risk factors for the development of "Torsades-de-Pointes" tachycardias (TdP). The molecular basis of this serious side effect has not been elucidated yet.

Are electrophysiological studies needed prior to defibrillator implantation?

At present, patients with documented sustained VT or resuscitated cardiac arrest (CA) are treated with ICDs. The aim of this study was to retrospectively evaluate if a routine electrophysiological study should be recommended prior to ICD implantation. In 462 patients referred for ICD implantation because of supposedly documented VT (n = 223) or CA (n = 239), electrophysiological study was routinely performed.

Ventricular oversensing: a study of 101 patients implanted with dual chamber defibrillators and two different lead systems.

Unlabelled: Modern dual chamber ICD systems are able to overcome various sensing problems. However, improvement of their performance is still required. The aim of this study was to assess the sensing function in 101 consecutive patients (84 men, 17 women; mean age 63 +/- 12 years; mean follow-up 24 +/- 4 months) implanted with dual chamber defibrillators and integrated (IB) or dedicated bipolar (DB) lead systems.

Bertosamil blocks HERG potassium channels in their open and inactivated states.

1. Bertosamil is chemically related to the class-III anti-arrhythmic drug tedisamil and has been developed as a bradycardic, anti-ischemic and anti-arrhythmic drug. Its anti-arrhythmic properties might in part be attributed to its block of voltage-dependent potassium channels Kv(1.

Vascular effects of class-III antiarrhythmic drugs: chromanol 293B, but not dofetilide blocks the smooth muscle delayed rectifier K+ channel.

Chromanol 293B and dofetilide are inhibitors of IKs and IKr, i.e., of the slow and the rapid component of the delayed rectifier potassium current.

Variability of Holter electrocardiographic findings in patients fulfilling the noninvasive MADIT criteria. Multicenter Automatic Defibrillator Implantation Trial.

In the MADIT study, a selected group of postinfarction patients with asymptomatic nonsustained ventricular tachycardia (NSVT) has been shown to benefit from prophylactic ICD treatment. The present study analyzed the variability of NSVT in a patient population fulfilling the non-invasive MADIT criteria. Three consecutive Holter ECGs were performed in weekly intervals in 68 postinfarction patients with an LVEF < or = 0.