HYPERTROPHIC CARDIOMYOPATHY (HOCM): A disease of Heart

HOCM

1. HYPERTROPHIC CARDIOMYOPATHY Dr Anurag Ghotkar Junior resident AIIMS Nagpur

2. Definition:-LVH in the absence of causes like hypertension, aortic valve disease, or systemic infiltrative or storage diseases

3. Two types –hypertrophic cardiomyopathy with or without obstruction. Prevalence in NorthAmerica , Africa, and Asia is about 1:500 It is the leading cause of sudden death in the young and is an important cause of heart failure Prognosis beter if presentation in adult >child

4. 100 percent genetic autosomal dominant sarcomere mutation ~60% of patients ~80% of patients have a mutation in either MYH7 or MYBPC3

5. At level of the sarcomere mutations lead to enhanced calcium sensitivity, maximal force generation, and ATPase activity. FAILURE TO RELAX , both directly and as a result of hypertrophy.

6. Disarrayed myocyte architecture swirling and branching arrangement of myocyte fibers. Myocyte nuclei vary markedly in size interstitial fibrosis is present. T he usual parallel pattern

7. Interstitial fibrosis is detectable before overt hypertrophy develops and likely results from early activation of profibrotic pathways. focal areas of replacement fibrosis can be readily detected with MRI. “scar” may represent substrate for the development of ventricular arrhythmias decreased luminal area of the intramural vessels contribute to microvascular ischemia and angina.

8. When to screen ? screening of family members- should begin in adolescence and extend through adulthood Hypertrophic cardiomyopathy is characterized by age-dependent and incomplete penetrance. The defining phenotype of LVH is rarely present at birth and usually develops later in life. In MYBPC3 mutation carriers, the average age of disease development is late i.e. 40 years

9. Patterns of hypertrophic remodeling Typically - nonuniform i.e. interventricular septum is the typical location of maximal hypertrophy Other patterns - concentric and midventricular. Apical hypertrophic Cardiomyopathy is less often familial and has less mutations Obstruction is present in ~30% of patients at rest and can be provoked by exercise in another~30%

10. Clinical presentation symptoms – exertional dyspnea 90%, angina 80%, syncope 20%. Aggravating factors – physical activity , digoxin (increase force of contraction ) , sympathomimetic drugs (increase HR) Pulse – pulsus bisferians Apex impulse – double or triple S2 paradoxical split S4 present

11. AFIB IS MOST COMMON ARRHYTHMIA IN HOCM Rx Amiodarone Avoid digoxin

12. 2DECHO - asymmetric hypertrophy of the septum compared to the lateral wall of the left ventricle (LV). mitral valve (MV) is moving anteriorly toward the hypertrophied septum in systole. left atrium (LA) is enlarged. Stroke volume decreases EF – WNL

13. LVH >15 TO 17 MM ASYMMETRIC >SYMMETRICAL SEPTAL HYPERTROPHY THE SEPTUM BULGING INTO THE LVOT CAUSING OBSTRUCTION.

14. Differential diagnosis Rigorous athletic training (athlete’s heart) is physiologic hypertrophy Features to differentiate – regresses with cessation of training, supernormal exercise capacity (VO2max >50 mL/kg per min), mild ventricular dilation, and normal diastolic function.

15. Prognosis Sudden death risk is <1% per year 1 in 20 patients will progress to overt systolic dysfunction (“burned out” or end-stage hypertrophic cardiomyopathy).

16. β-Adrenergic blocking agents and L-type calcium channel blockers slow AV nodal conduction and improve symptoms Disopyramide and amiodarone are the preferred antiarrhythmic agents radiofrequency ablation for medically refractory cases. Anticoagulation to prevent embolic stroke in atrial fibrillation .

17. Disopyramide- an antiarrhythmic agent with potent negative inotropic properties can help if Persistent symptoms of exertional dyspnea or chest pain Severe medically refractory symptoms -surgical myectomy or alcohol septal ablation may be effective- relieves outflow tract obstruction by excising part of the septal myocardium involved in the dynamic obstruction. Alcohol septal ablation in patients with suitable coronary anatomy can relieve outflow tract obstruction via a controlled infarction of the proximal septum, which produces similar periprocedural outcomes and gradient reduction as surgical myomectomy. With both procedures, the most common complication is the development of complete heart block necessitating permanent pacing.

18. Thank you