This study demonstrates that it is possible to reproducibly induce self-terminating AF and supraventricular arrhythmias in mice by transesophageal atrial burst stimulation. The presented method allowing serial testings of the same animal can be a useful tool in further investigations with transgenic mice and might be helpful in the characterization of underlying genetic or molecular mechanisms of AF.

The present study implies that initiation of amiodarone therapy in pts with structural heart disease and AF that are concomitantly treated with beta-blockers and digitalis may have an increased risk of amiodarone-associated pro-arrhythmia.

Although patients suffering from heart failure (HF) have an increased incidence of nonocclusive mesenteric ischemia after opened heart surgery, the impact of cardiopulmonary bypass with cardiac arrest (CPB) on mesenteric vascular circulation in such situation remains unexplored. Therefore, the present study investigates the effects of CPB on mesenteric vascular reactivity, regional metabolism, and oxidative stress in an experimental model of HF. Volume-overload HF was induced in six dogs by bilateral femoral arteriovenous fistula. Six sham-operated dogs were used as controls. Eight weeks later, the short-term effects of 90 min of CPB were assessed in vivo during acute experiments. The significant increase in left ventricular end-diastolic volume in HF animals did not influence the vasodilator response of the superior mesenteric artery to acetylcholine (ACH) and nitroprusside (SNP) under baseline conditions. However, reduced mesenteric oxygen delivery, increased oxygen extraction, and lactate release were found during CPB in the HF group. In addition, an increased free radical production was assessed in the HF group during (89 +/- 23 x 10 relative light units [RLU]) and after CPB (93 +/- 15 x 10 RLU) compared with controls (45 +/- 15 and 49 +/- 7 x 10 RLU, respectively). Finally, 90 min of CPB led to a more pronounced decrease of ACH- (-22% +/- 5% vs. -42% +/- 9%, P < 0.05) and SNP- (-14% +/- 4% vs. -50% +/- 7%, P < 0.002) induced mesenteric vasodilations in the HF group compared with controls. We conclude that coexistent HF significantly enhances the pathological effects of CPB on the mesenteric vascular circulation by additionally altering endothelial and smooth muscle vascular function consequent to augmented oxidative stress.

Pacing algorithms to prevent PAF are mainly based on the suppression of premature atrial complexes (PACs), which play an important role in its initiation. In contrast to 24-hour ambulatory electrocardiograms, advanced pacemaker (PM) diagnostic features are capable of recording AF episodes during long follow-up periods and of characterizing AF in a detailed fashion. For the specific use of these algorithms, a detailed characterization of AF was performed in 91 dual chamber PM recipients with histories of AF. Fifteen patients with episodes of oversensing due to far-field signals or frequent episodes of "2:1-undersensing" of atrial flutter were excluded. The remaining 76 patients had high recurrence rates of AF (median 0.8 episodes/day), however, the majority of episodes lasted < 7 minutes. Despite frequent PACs (median 10.8/hour) during sinus rhythm, a median of 66.4% of the AF episodes were preceded by < 2 PACs/min before onset. In conclusion, frequent, short-lived AF episodes seem best suited for AF preventive pacing therapies. However, the small number of PACs preceding many AF episodes may limit the efficacy of PAC suppressing algorithms.

No abstract

We report a case study demonstrating delayed circumferential intrapulmonary-venous conduction characteristics during coronary sinus extrastimulus pacing. This phenomenon allowed the unmasking and discrimination of a localized left atrial to PV breakthrough from secondarily activated PV muscle in a common left-sided PV ostium. Thus, this pacing manoeuvre may serve to guide RF delivery in the treatment of focal AF.

The authors review the history of atrial fibrillation, the most frequent clinically observed cardiac arrhythmia. A French "clinicopathologist", Jean Baptist de Sénac (1693-1770), was the first who assumed a correlation between "rebellious palpitation" and a stenosis of the mitral valve. From an analysis of simultaneously recorded arterial and venous pressure curves, the Scottish Sir James Mackenzie (1853-1925) demonstrated that a presystolic a wave cannot be seen on the jugular phlebogram during "pulsus irregularis perpetuus". The first human ECG depicting atrial fibrillation was published by Willem Einthoven (1860-1927) in 1906. The proof of a direct connection between absolute arrhythmia and auricular fibrillation was established by two Viennese physicians, Rothberger and Winterberg. The major discoveries relating to the pathomechanism and the clinical features of atrial fibrillation in the 20(th) century stemmed from the scientific activities of Karel Frederik Wenckebach, Sir Thomas Lewis, Gordon Moe, and Maurits Allessie.

Tetralogy of Fallot is the most common cyanotic cardiac malformation in late childhood and adult, occurring in approximately 0.25 of 1000 live births. Most patients undergo early surgical correction. Therefore, the natural history of this disease has been evaluated in only a few cases. We report a complex case of a tetralogy of Fallot, who reached the age of 74 years without surgical or medical treatment and who was transferred to our clinic after syncope due to ventricular tachycardia.