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CLINICAL RESEARCH: HEART RHYTHM DISORDER

Tachycardia-Mediated Cardiomyopathy Secondary to Focal Atrial Tachycardia

Long-Term Outcome After Catheter Ablation

Caroline Medi, BMed^_*,, Jonathan M. Kalman, MBBS, PhD^_*, Haris Haqqani, MBBS^_*, Jitendra K. Vohra, MD^_*, Joseph B. Morton, MBBS, PhD^_*, Paul B. Sparks, MBBS, PhD^_* and Peter M. Kistler, MBBS, PhD^_*,,_*

^_* Department of Cardiology, Royal Melbourne Hospital, and the Department of Medicine, University of Melbourne, Melbourne, Australia
Department of Cardiology, The Alfred Hospital, Melbourne, Australia
Baker Heart Research Institute, Melbourne, Australia

Manuscript received September 15, 2008; revised manuscript received January 26, 2009, accepted February 13, 2009.

^_* Reprint requests and correspondence: Dr. Peter M. Kistler, Department of Cardiology, The Alfred Hospital, Melbourne 3004, Australia (Email: peter.kistler{at}bakeridi.edu.au).

Objectives: This study aimed to characterize the incidence, clinical and electrophysiologic features, and long-term outcomes of patients with tachycardia-mediated cardiomyopathy (TCM) secondary to focal atrial tachycardia (AT).

Background: TCM is known to complicate atrial tachyarrhythmias. Little is known of the patient and tachycardia characteristics associated with the development of left ventricular (LV) dysfunction and the long-term outcomes after cure of tachycardia.

Methods: A total of 345 patients with focal AT underwent radiofrequency ablation between January 1997 and July 2008. A retrospective analysis was performed to identify patients with LV dysfunction, defined as an ejection fraction <50% on echocardiography. Patients with pre-existing structural heart disease (n = 14) were excluded. Patients with TCM (n = 30) and without TCM (n = 301) were compared. Recovery of LV function was also assessed.

Results: The incidence of TCM was 10%. Incessant or very frequent paroxysmal tachycardia was strongly associated with TCM, compared to patients without TCM (100% vs. 20%, p < 0.001). Patients in the TCM group were younger (mean age 39 ± 22 years vs. 51 ± 17 years, p = 0.0006) and more frequently male (60% vs. 38%, p < 0.001). Patients with TCM had a longer mean tachycardia cycle length (502 ± 131 ms vs. 402 ± 105 ms, p < 0.0001) and slower ventricular rate (117 ± 21 beats/min vs. 141 ± 33 beats/min, p = 0.0007) during tachycardia compared with patients who did not have TCM. Appendage sites are associated with a high incidence of incessant tachycardia (84%) and LV dysfunction (42%). After successful ablation, LV function was restored in 97% of patients at a mean of 3 months.

Conclusions: Cardiomyopathy occurs in 10% of patients with focal AT. A slower incessant tachycardia is more frequently complicated by cardiomyopathy. Long-term restoration of LV function can be achieved after successful catheter ablation of the tachycardia focus.

Key Words: atrial tachycardia • cardiomyopathy • tachycardia-mediated cardiomyopathy

Abbreviations and Acronyms   AT = atrial tachycardia   AV = atrioventricular   EP = electrophysiology   LV = left ventricular   LVEF = left ventricular ejection fraction   RFA = radiofrequency ablation   TCL = tachycardia cycle length   TCM = tachycardia-mediated cardiomyopathy

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J. Am. Coll. Cardiol. 2009 53: A30. [Full Text] [PDF]