DUAL-CHAMBER CARDIOVERTER DEFIBRILLATOR IMPLANTATION IN HYPERTROPHIC CARDIOMYOPATHY- CASE REPORT
Background: Several cohort trials showed that implantation of dual-chamber pacemaker in patients with severely symptomatic hypertrophic obstructive cardiomyopathy can releve symptoms and decrese the severity of the left ventricular outflow tract gradient.
Case outline: A 25-year-old men was addmited to Coronary care unite due to weakness,fatigue and after aborted sudden cardiac death.The resuscitation was performed in the first aid department.At the late time he suffered from fainting and palpitations.There was no family history of sudden death.The diagnose of hypertrophic cardiomyopathy was made from the early childhood,but his twin-brother had no heart disease.
At the addmision electrocardiogram showed normal rhythm and normal ST segment pattern,but ECG at the onset of symptoms showed VF and sustained VT successfully treated with DC shock.Physical examination was normal except rough systolic murmur on chest. Laboratory investigation revealed normal serum cardiac troponin T and serum potassiuma. Echocardiographic finding showed signs of hypertrophyc cardiomyopathy with thick wall(1,9/1,6 cm),and gradient of left ventricular outflow tract of 76/40 mmHg. There was deformation of mitral leaflets and moderate mitral regurgitation. HolterECG showed ventricular extrasystoles arrhythmia and increased vagal tone. The indication of secondary prevention of sudden cardiac death(SCD) was made.The patient was considered as high risk and he underwent dual-chamber ICD implantation(right ventricular ICD electrode and atrial passive electrode). Nonivasive electro- physiology study was performed demonstrated inducible polymorphic VT (stopped with 30J DC shock). The parameters of electrical stimulation was changed (AVsensed/AVpaced 80/100 msec) to ensure permanent right ventrivular pacing. After three months the gradient of LVOT was not decreased,so we performed ICD in VVI mod with antibradicardia back up of 40/min. After next six months of follow up still there were no VT/VF or therapy dilivery. Echocardiographic measurements were not changed.The patient was out of symptoms.
Conclusion: Although dual-chamber pacingmay releive symptoms and decrease gradient in patients with hypertrophic cardiomyopathy, in some patients, however, symptoms and gradient do not change.