Multifocal atrial tachycardia, also designated "chaotic atrial tachycardia," was identified in the records of 31 patients. It was particularly noted that the arrhythmia progressed to atrial fibrillation or flutter in 17 cases (55%). Unifocal or multifocal premature atrial contractions preceded the arrhythmia in 20 cases (64%). The arrhythmia developed during an acute illness in 18 cases (58%). ...

A case of incessant supraventricular tachycardia continuing despite AV block is reported. Atrial tachycardia and AV nodal reentrant tachycardia were excluded, as was orthodromic tachycardia using a concealed accessory AV pathway. The earliest retrograde atrial activation was at the posterolateral tricuspid annulus, and the tachycardia was eliminated by ablation at this site. The findings in thi...

To investigate the mechanisms of polyuria associated with tachycardia, we measured plasma concentrations of alpha-human atrial natriuretic polypeptide (alpha-hANP) and cGMP in 6 patients with paroxysmal tachycardia. Plasma concentrations of immunoreactive alpha-hANP and cGMP increased by +69% (p less than 0.05) and +100% (p less than 0.05), respectively, during both paroxysmal atrial tachycardi...

We present a case of a single chamber atrial pacemaker implanted for sinus node dysfunction and treatment of macroreentrant atrial tachycardias with atrial antitachycardia pacing. The patient presented with sustained atrial tachycardia above the detection rate, however, the device was unable to detect the tachycardia and did not deliver the programmed therapy. We discuss the nuances of the atri...

BACKGROUND Ca(2+) overload is believed to play a role in tachycardia-induced atrial electrophysiological remodeling. L-type Ca(2+) channel blockers attenuate effective refractory period (ERP) changes caused by 24 hours of atrial tachycardia but may not substantially alter atrial fibrillation (AF) inducibility. This study assessed the effects of the T-type Ca(2+) channel blocker mibefradil on ta...

Background—Ca overload is believed to play a role in tachycardia-induced atrial electrophysiological remodeling. L-type Ca channel blockers attenuate effective refractory period (ERP) changes caused by 24 hours of atrial tachycardia but may not substantially alter atrial fibrillation (AF) inducibility. This study assessed the effects of the T-type Ca channel blocker mibefradil on tachycardia-in...

Fig.1 shows a premature atrial complex (PAC) introduced during a narrow QRS tachycardia. What is the response and what is the interpretation? The tachycardia is a regular RBBB tachycardia with cycle length of 440 ms and ventriculo-atrial interval of 30 ms. There is near simultaneous activation of atrium and ventricle during tachycardia. Presence of His deflection prior to the QRS makes ventricu...

Pulmonary vein isolation has become the cornerstone of ablation for atrial fibrillation. However, it is sometimes followed by the development of left atrial macro-reentrant tachycardia. There is evidence to suggest that the myocardial sleeves within the pulmonary veins may be implicated in the mechanism of the tachycardia. Here we present a case of a post-ablation macro-reentrant tachycardia, i...

We report a case of apparent isolation of the right inferior pulmonary vein during atrial fibrillation ablation coincident with the onset of an atrial tachycardia. This report highlights the importance of assessing pulmonary vein conduction during sinus or paced rhythm at relatively long cycle length, rather than in atrial fibrillation or atrial tachycardia.

AIMS To assess the results of transcatheter ablation of cardiac arrhythmias in Latin America and establish the first Latin American transcatheter ablation registry. METHODS AND RESULTS All ablation procedures performed between 1 January and 31 December 2012 were analysed retrospectively. Data were obtained on the characteristics and resources of participating centres (public or private instit...