Pediatric Intensive Care Unit, Hippokration General Hospital, Greece.
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We describe a 6 year-old boy who was admitted in the pediatric intensive care unit in cardiogenic shock due to incessant supraventricular tachycardia (SVT) (Fig. 1) Examination revealed poor skin perfusion in a pale, lethargic boy with elevated heart rate of 180 beats per minute with a 3-day history of palpitations, fatigue and poor feeding. His past medical history included an episode of paroxysmal SVT after a viral infection at 3 years of age which was successfully managed with amiodarone, propaphenone and propranolol. Initial resuscitation required rapid fluid administration, inotropic support and mechanical ventilation. Initial chest radiography showed cardiomegaly and pulmonary venous congestion. Troponin levels were elevated at 0,76 ngD L. Transthoracic echocardiography revealed a dilated left ventricle with hypokinesia, markedly reduced left ventricular ejection fraction (LVEF) around 26% without any congenital cardiac defects. The patient rapidly developed multiorgan failure. Acute myocarditis was excluded due to absence of abnormal T wave inversion and high serum CK level. Blood and peripheral culture(s) together with serology, were negative. There was no histological evidence of inflammation on biopsy. The patient was gradually weaned off inotropic support and mechanical ventilation, while antiarrhythmic medication with amiodarone with digoxin and propranolol was initiated due to rhythm disturbances.Ventricular function improved gradually and myocardial biopsy after cardiac catheterization revealed dilated cardiomyopathy, without histological evidence of inflammation. At one year follow-up the patient remains asymptomatic with normal left ventricular size on echocardiography and a LVEF of 67%, confirming the diagnosis of tachycardia induced cardiomyopathy.

Fig. 1 ECG at presentation indicative of paroxysmal supraventricular tachycardia.

In children, SVT is the most common tachyarrhythmia. When SVT is incessant, it can lead to tachycardia induced cardiomyopathy which presents as heart failure [1]. The condition is characterized by significant cardiac enlargement, reduced ventricular wall thickness, and impaired ventricular contraction that resembles to dilated cardiomyopathy but are after control of tachyarrhythmia and management of heart failure [2,3]. A high index of suspicion is mandatory for the diagnosis of tachycardia induced cardiomyopathy. On ECG, the arrhythmia becomes evident. Chest X-ray is also helpful but it is the echocardiogram that reveals LV and left atrial (LA) dilatation with reduced LVEF. Differential diagnosis includes other causes of reversible cardiac dysfunction such as coronary artery disease hypertension, myocarditis, alcohol, Takotsubo–stress cardiomyopathy, and sepsis. LV dimensions can be used to differentiate dilated cardiomyopathy accompanied by supraventricular tachycardia. Restoration of a normal heart rate improves LV systolic function and reverses clinical manifestations of heart failure in patients with tachycardia induced cardiomyopathy [4].

This is a rare and potentially treatable cause of acute heart failure. A high index of clinical suspicion is mandatory for prompt diagnosis and immediate initiation of treatment.

Acknowledgements: Our sincere thanks to Dr. Helen Volakli and Dr. Asimina Violaki for their assistance in the management of the patient and the data collection of this paper.

1. Cruz FE, Cheriex EC, Smeets JL, Atie J, Peres AK, Penn OC, et al. Reversibilty of tachycardia induced cardiomyopathy after cure of incessant SVT. J Am Coll Cardiol. 1990;16:739-44.

2. Mclaran CJ, Gersh BJ, Sugrue DD, Hammill SC, Seward JB, Holmes DR Jr, et al. Tachycardia induced myocardial dysfunction. A reversible phenomenon? Br Heart J. 1985;53:323-7.

3. Jeong YH, Choi KJ, Song JM, Hwang ES, Park KM, Nam GB, et al. Diagnostic approach and treatment strategy in tachycardia-induced cardiomyopathy. Clin Cardiol. 2008;31:172-8.

4. Lishmanov A, Chockalingam P, Senthilkumar A, Chockalingam A. Tachycardia-induced cardiomyopathy: evaluation and therapeutic options. Congest Heart Fail. 2010;16:122-6.