[Tachycardia-induced cardiomyopathy, unusual and reversible cause of left ventricular dysfunction: report of 9 cases]

In this study, 9 cases of tachycardia-induced cardiomyopathy have been reported, with a 7-year follow-up period. The patient population consisted of 5 males and 4 females with a mean age of 41 +/- 18 years (range: 10-70 years). It was difficult to determine the onset of the arrhythmia, due to its frequently asymptomatic course until such time as cardiac insufficiency became apparent (this was the case in 7 patients, while 2 subjects had palpitations). Four cases of AV intranodal reentry tachycardia (3 with an accessory pathway), 2 cases of atrial fibrillation, 1 case of auricular flutter, 1 case of atrial tachycardia and 1 case of ventricular tachycardia were observed. Disappearance of the symptomatology following restoration of sinus rhythm was accompanied by echocardiographically-determined normalization of systolic function on average 5 +/- 4 months post-arrhythmia (range: 1-12 months). Left-ventricular end-diastolic volumes decreased from 60 +/- 5 mm to 51 +/- 4 mm (P < 0.01), and end-systolic volumes from 50 +/- 7 mm to 35 +/- 4 mm (P < 0.001), while the left ventricular shortening fraction increased from 17 +/- 5% to 33 +/- 4% (P < 0.0001). In the differential diagnosis for primary dilated cardiomyopathy, tachycardia-induced cardiomyopathy appears very similar to the former, and only an adequate period of follow-up after the restoration of sinus rhythm can confirm the diagnosis.