Background
Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac disorder and has been estimated to occur in one of every 500 persons in the general population. The mortality due to HCM is estimated at 1% per year and it is the most common reason of sudden death (especially in young athletes). The natural history of HCM can be altered by a number of therapeutic interventions: ICDs for secondary or primary prevention of sudden death in patients with risk factors, drugs appropriate to control heart failure symptoms, surgical septal myectomy or alcohol septal ablation for progressive and drug-refractory heart failure caused by LVOT obstruction, heart transplantation for systolic (or less frequently, intractable diastolic) dysfunction associated with severe symptoms, and drug therapy or possibly radiofrequency ablation or surgical maze procedure for AF.
Case presentation
19-year-old patient with Down syndrome, ostium secundum atrioventricular septal defect , ventricular septal defect, persistent ductus Botalli, after total surgical correction in the 5th year of age. The patient was diagnosed hypertrophic cardiomyopathy when he was 10. From that time he had been systematically monitored by cardiologist. When he was 18, he became the patient of Grow-up Congenital Heart Outpatient Clinic of The John Paul II Hospital in Cracow. Due to severe mental retardation, it was impossible to obtain the case history from the patient. Thus, he was under permanent care of his mother, according to whom, the patient was demonstrating mild decrease of exercise capacity during recent years (in class I/II by NYHA; the patient regularly participates in exercises, e.g. dancing) and fatigue with apathy lastly. She has denied episodes of presyncope or syncope and cases of sudden death in their family. Up to date, he was treated by verapamil 80 mg per day. On examination systolic murmur across the sternum was heard. ECG revealed atrioventricular dissociation with HR 45 bpm, right axis deviation, Q wave in I, II, III, aVF, V4-V6, inverted T waves in III, aVF, right bundle branch block, signs of right and left ventricle hypertrophy and QTC 420 ms. 24- hours ECG has showed basic sinus rhytm 50 bpm (max. 94, min. 37) and the episodes of atrioventricular dissociation. The echocardiography has revealed concentric hypertrophy of left ventricle with interventricular septum diameter 26 mm, systolic anterior movement of anterior mitral valve leaflet and moderate mitral regurgitation. Furthermore, the turbulent flow in left ventricular outflow tract (LVOT) with pressure gradient in LVOT 57 mm Hg was revealed. Finally, the echocardiography showed diastolic dysfunction of the muscle.
Guidelines
According to ACCF/AHA guidelines for the diagnosis and treatment of hypertrophic cardiomyopathy, 2011, an invasive therapies – septal reduction therapy, should be performed only for the treatment of eligible patients with severe drug-refractory symptoms and LVOT obstruction ( Class I C):
– Clinical: Severe dyspnea or chest pain (usually New York Heart Association [NYHA] functional classes III or IV) or occasionally other exertional symptoms (such as syncope or near syncope) that interfere with everyday activity or quality of life despite optimal medical therapy
– Hemodynamic: Dynamic LVOT gradient at rest or with physiologic provocation ≥50 mm Hg associated with septal hypertrophy and systolic anterior motion (SAM) of the mitral valve
– Anatomic: Targeted anterior septal thickness sufficient to perform the procedure safely and effectively in the judgment of the individual operator.
According to the guidelines, ICD placement is recommended for patients with HCM with prior documented cardiac arrest, ventricular fibrillation, or hemodynamically significant VT (Class I B). It is reasonable to recommend an ICD for patients with HCM with (Class II a):
– Sudden death presumably caused by HCM in 1 or more first-degree relatives
– A maximum LV wall thickness greater than or equal to 30 mm
– One or more recent, unexplained syncopal episodes
– An ICD can be useful in select patients with NSVT (particularly those <30 years of age) in the presence of other SCD risk factors or modifiers
– An ICD can be useful in select patients with HCM with an abnormal blood pressure response with exercise in the presence of other SCD risk factors or modifiers
– It is reasonable to recommend an ICD for high-risk children with HCM, based on unexplained syncope, massive LV hypertrophy, or family history of SCD, after taking into account the relatively high complication rate of long-term ICD implantation.
References
1. ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy, 2011
2. AHA/ESC guideline for the diagnosis and treatment of hypertrophic cardiomyopathy, 2003
Authors:
Prof. Piotr Podolec MD, PHD1, Monika Smaś-Suska MD1, Lidia Tomkiewicz-Pająk MD1, Maria Olszowska MD PhD1
1 Department of Cardiac and Vascular Diseases, Jagiellonian University College of Medicine, John Paul II Hospital, Krakow, Poland
