5 points to remember about cardiac genetic conditions

1.  Primary electrical syndromes are detected on a baseline ECG.  The most common is long QT syndrome.  Causes of long QT on ECG include acquired (commonly drugs, see crediblemeds.org, electrolytes) and genetic causes (long QT syndromes).  Patients with long QT should have risk scoring, genetic testing and counseling.  Most cases of long QT syndrome are managed with beta blockers, but some cases require cardiac defibrillators. 

2. Brugada syndrome should be looked for on ECG. Patients with suspected Brugada syndrome require additional testing to exclude underlying structural heart disease, myocardial ischemia and further risk stratification for ventricular arrythmia risk. Those with a confirmed diagnosis should avoid certain triggers including fever and certain medications (brugadadrugs.org).

3.  Catecholaminergic polymorphic ventricular tachycardia, is diagnosed by an exercise stress test that shows increased frequency of nonsustained or sustained VΤ during exercise or recovery.  Initial management involves beta blockers and if refractory, consideration of an ICD, rarely flecainide or sympathetic denervation.

4. Short QT syndrome is rare. Typical ecg features include a QT interval <360 milliseconds, (generally less then 330 ms), tall and peaked T waves in the precordial leads, poor rate adaptation of the QT interval. Secondary causes include metabolic, electrolytes (potassium, calcium) and drugs.

5.  Hypertrophic cardiomyopathy is a relatively common condition.  It can manifest as an abnormal EKG, symptoms or sudden cardiac death. Genetic counseling, testing and family screening is recommended in all patients with suspected hypertrophic cardiomyopathy. Genetic testing is also recommended in many young patients with dilated cardiomyopathy or those who have a family history of dilated cardiomyopathy.  Other rare diseases that benefit from genetic testing and evaluation include arrhythmogenic right ventricular cardiomyopathy (ARVC), restrictive cardiomyopathy and some muscular dystrophies.