Paroxysmal Supraventricular Tachycardia with QRS Duration Alternans, Electrical Alternans, and Pulsus Alternans but without Cycle Length Alternans.
We reported a 60-year-old male patient who had a paroxysmal supraventricular tachycardia with QRS duration alternans (alternation between narrow QRS and wide QRS beats) and electrical alternans, but without any cycle length alternans. In the laboratory, slow-fast atrioventricular nodal reentrant tachycardia was easily induced by an atrial extrastimulus, and the arterial pressure recordings displayed a simultaneous pulsus alternans during tachycardia. The patient also underwent coronary angiography which revealed a total occlusion of the left anterior descending artery. In this report, we have proposed that the QRS duration alternans, electrical alternans and pulsus alternans during the paroxysmal supraventricular tachycardiamay have been due to the prolongation of the effective refractory period of the right bundle branch, caused by myocardial ischemia.


BACKGROUND
Electrical alternans; Myocardial ischemia; Supraventricular tachycardia.
Division of CardiovascularMedicine, Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University;
Wei-Ta
WT
Chen
Division of CardiovascularMedicine, Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University;
Ho-Shun
HS
Cheng
Division of CardiovascularMedicine, Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University; ; Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Jen-Hung
JH
Huang
Division of CardiovascularMedicine, Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University; ; Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
Ming-Hsiung
MH
Hsieh