Objective: To assess the true efficacy of antitachycardia pacing on spontaneous persistent atrial fibrillation in patients with an implanted atrial defibrillator, by comparing the effects of nominal pacing treatment with subthreshold pacing treatment. Design: The effects of antitachycardia pacing and burst 50 Hz atrial pacing on spontaneous atrial arrhythmias were evaluated six months after imp...

We studied exercise performance before and after conversion of atrial tachycardia to sinus rhythm, atrial bradycardia, or junctional rhythm in 10 patients 9-25 years of age 8-20 years after congenital heart disease surgery (complete transposition of the great arteries, seven of 10 patients). The same maximal cycle (five of 10 patients) or treadmill (five of 10 patients) exercise protocol was pe...

Presentation A 19-year-old male with congenitally corrected transposition of the great arteries (ccTGA; S, L, L–situs solitus, l-loop, l-transposition) presented with recurrent frequent palpitations, fatigue, and effort intolerance. Previous history was significant for initial presentation with supraventricular tachycardia (SVT) at the age of 14 years. Transthoracic echocardiography at that tim...

A female patient was admitted to our hospital for catheter ablation arising from paroxysmal supraventricular tachycardia (PSVT). In the laboratory, PSVT (the earliest retrograde atrial activation at the coronary sinus ostium) with intermittent atrioventricular (AV) block could be induced repeatedly. The tachycardia could be terminated during ventricular pacing without retrograde conduction to t...

BACKGROUND Tachycardia-induced cardiomyopathy is a reversible cause of heart failure. We hypothesized that although left ventricular ejection fraction measurements normalize after heart rate or rhythm control in patients with tachycardia-induced cardiomyopathy, recurrent tachycardia may have abrupt and deleterious consequences. METHODS AND RESULTS Patients with tachycardia-induced cardiomyopa...

BACKGROUND The relationship between autonomic activation and the mechanisms of paroxysmal atrial fibrillation remains unclear. METHODS AND RESULTS We implanted a pacemaker and a radio transmitter in 7 dogs (group 1). After baseline recording, we paced the left atrium at 20 Hz for 1 week and then monitored left stellate ganglion nerve activity, left vagal nerve activity, and left atrial electr...

Doppler studies at rest suggest left ventricular (LV) diastolic function rapidly improves from the neonate to infant. Whether this translates to its response to hemodynamic challenges is uncertain. We sought to explore the impact of early LV maturation on its ability to tolerate atrial tachycardia. As tachycardia reduces filling time, we hypothesized that the neonatal LV would be less tolerant ...

A 27-year-old man with a 10-year history of recurrent episodes of paroxysmal supraventricular tachycardia underwent an electrophysiologic procedure. The baseline sinus cycle length was 860 msec, and the atrial-His (AH) and Hisventricular (HV) intervals were 80 and 45 msec, respectively. A narrow QRS-complex tachycardia was induced by atrial overdrive pacing. The cycle length of the tachycardia ...

Pacemakers were implanted in 10 of 14 patients with dizziness and syncopal episodes of long duration, due to sino-atrial block. Paroxysmal supraventricular tachycardia, notably atrial fibrillation, had occurred in 6 patients. Medical treatment was unsatisfactory in 3 of these and pacemaker therapy was given. This abolished both syncope and paroxysmal tachycardia. Sinoatrial block and supraventr...

BACKGROUND Conventional methods to assess local activation time (LAT) detect the peak of the bipolar electrogram (B-LATPeak) or the maximal negative slope of the unipolar electrogram (U-LATSlope). We evaluated 3 novel methods to assess LAT: onset (B-LATOnset) and center of mass (B-LATCoM) of bipolar electrogram, and maximal negative slope of unipolar electrogram within a predefined bipolar wind...