Medical therapy of HCM:
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> In asymptomatic HCM patients, benefit from beta blockers or L-type calcium channel blockers has not been established, but beta blockers are first-line agents for the management of symptomatic (angina or dyspnoea) patients with HCM.
> The addition of disopyramide to beta blocker therapy or the use of verapamil alone may be beneficial in those who do not respond to beta blockers. Vasodilators, including dihydropyridine calcium channel blockers and angiotensin-converting enzyme inhibitors, are potentially harmful in those with evidence of LVOT obstruction.
> Beta blockers , particularly without intrinsic sympathomimetic activity and aimed at heart rate <60–65 bpm, improve ventricular relaxation, increase diastolic filling time, and should theoretically reduce susceptibility to ventricular arrhythmias. They are the mainstay of treatment for symptomatic improvement.
> L-type calcium channel blockers , such as verapamil (starting in low doses and titrating up to 480 mg/day) and diltiazem , are beneficial due to negative inotropic and chronotropic effects and improved diastolic function and are used instead of, or with, beta blockers.
They may, however, exacerbate LVOT gradient due to vasodilation. They are particularly useful in the non-obstructive form.
> Disopyramide , in combination with beta blockers, reduces LVOT gradient and improves symptoms by its negative inotropic action. Although it has not been considered proarrhythmic in HCM,
> Amiodarone is not considered a therapeutic option for prevention of sudden death in HCM any more