In adults a tachycardia is any heart rate greater than 100 beats per minute. Supraventricular tachycardias may be divided into two distinct groups depending on whether they arise from the atria or the atrioventricular junction. This article will consider those arising from the atria: sinus tachycardia, atrial fibrillation, atrial flutter, and atrial tachycardia. Tachycardias arising from re-ent...

Current classifications of regular atrial tachycardias have been based exclusively on the ECG. Differentiation between atrial flutter and atrial tachycardia depends on a rate cut-off around 240–250/min and the presence of isoelectric baselines between atrial deflections in atrial tachycardia, but not in atrial flutter. However, atrial tachycardia mechanisms, defined by electrophysiological stud...

We describe a case of atrial tachycardia originating from an epicardial site with a venous connection between the left superior pulmonary vein (LSPV) and superior vena cava (SVC). Initial endocardial mapping with multiple electrodes catheters demonstrated early endocardial activation at both the SVC and LSPV. However, radiofrequency applications at the SVC failed to terminate the atrial tachyca...

BACKGROUND The existence of an atypical fast-slow (F/S) atrioventricular nodal reentrant tachycardia (AVNRT) including a superior (sup) pathway with slow conductive properties and an atrial exit near the His bundle has not been confirmed. METHODS AND RESULTS We studied 6 women and 2 men (age, 74 ± 7 years) with sup-F/S-AVNRT who underwent successful radiofrequency ablation near the His bundle...

We report a rare case of atrial tachycardia originating from the non-coronary aortic sinus. After failed radiofrequency (RF) energy applications at right His-bundle region, the complete elimination of atrial tachycardia was achieved with an RF energy application in the non-coronary aortic sinus. With the review of other papers, this report emphasizes the importance of mapping in the non-coronar...

OBJECTIVES Indirect evidence suggests a role for Ca(2+)-overload in electrical and mechanical alterations caused by atrial tachycardia. The present study assessed the alterations in cellular [Ca(2+)] and contractile function caused by rapid atrial cellular activation. METHODS Intracellular Ca(2+) transients (CaT) and cell shortening (CS) were measured by microfluorometry (Indo-1 AM) and video...

In case 1, a 71-year-old man with a history of coronary artery disease presented with recurrent paroxysmal supraventricular tachycardia (SVT) despite treatment with -blockers. During electrophysiology study, the baseline sinus cycle length was 895 ms, atrial-His (AH) interval was 120 ms, and His-ventricular interval was 60 ms. A narrow complex SVT with tachycardia cycle length of 480 ms was ini...

We have developed a microcomputer algorithm for tachycardia identification suitable for use in an implanted antitachycardia pacemaker. The algorithm distinguishes atrial, ventricular, and AV reentrant tachycardia, while ignoring high rates due to sinus tachycardia. A new method whereby the pacemaker delivers an atrial extrastimulus has been developed for distinguishing paroxysmal 1:1 tachycardi...

We report on the characteristics and the ablation procedure of a focal atrial tachycardia originating from the non-coronary aortic cusp. The electrophysiological features of the tachycardia included: (i) incessant pattern; (ii) easy induction and termination by atrial stimulation; (iii) earliest right atrial activation at the para-hisian area; and (iv) termination by adenosine. Left-sided mappi...

The mechanisms of supraventricular tachycardia were investigated in 35 children. Intracardiac electrograms including His bundle potentials were recorded. Atrial pacing and single premature atrial stimuli were performed in the right atrium. Tachycardia was observed and the mechanism elucidated in 33 patients. The atrial activation sequence during tachycardia, including high right atrium, low lat...