Hereditary Cardiac Arrhythmia
|TAT (TURNAROUND TIME)||2 - 4 weeks|
|CPT CODE||81439, 81479|
|RECOMMENDED MNG KITS||
Cardiac arrhythmias occur due to disruption of the heart’s natural rhythm. An arrhythmia can be caused by structural abnormalities of the heart, electrolyte imbalance, trauma, and genetic disorders. There are several different genetic arrhythmia disorders and multiple genes are associated. Hereditary arrhythmia disorders are found in more than half of all initially unexplained cases of sudden cardiac death in young individuals. In these cases of sudden death, 30% is found to be caused by an arrhythmogenic structural heart disease with increased arrhythmia risk. 70% is caused by a primary hereditary arrhythmia disorder due to dysfunction of the ion channels of the cardiac muscle. Hereditary arrhythmia disorders are rare, but early diagnosis can markedly reduce the risk of sudden cardiac death.
Structural Arrythmias include hypertrophic (obstructive) cardiomyopathy (HOCM, HCM), dilated cardiomyopathy (DCM), arrhythmogenic right-ventricular cardiomyopathy/dysplasia (ARVC/D), and left-ventricular noncompaction. Symptoms can vary between affected family members and range from asymptomatic to progressive heart failure, to sudden cardiac death.
Primary arrhythmia syndromes include Long and Short-QT syndromes, Brugada syndrome, and Catecholaminergic polymorphous ventricular tachycardia (CPVT). Typical first symptoms of ion channel diseases are palpitations, brief loss of consciousness with spontaneous recovery, or arrhythmogenic seizures, especially if these have specific triggers (physical effort, stress, sudden noises).
|Acceptable Sample Types||
|Sample Preparation:||(1) Blood specimens: Draw blood in an EDTA tube. Preferred volume: 4 milliliters (adults and pediatrics), Minimum volume: 2 milliliters; (2) DNA extracted from leukocytes, muscle, or fibroblasts: Preferred quantity: 4 micrograms, Minimum quantity: 3 micrograms (Genomic DNA should be eluted in sterile Dnase/Rnase free water or TE. The A260:A280 ratio should be 1.8-2.0.); (3) 2 T-25 flasks of fibroblasts; (4) 50-75 milligrams muscle snap frozen in liquid nitrogen and maintained at -80°Celsius or below. (5) Skin biopsy (Fibroblasts will be cultured from skin specimen for genetic testing): Skin biopsy may be taken from the inner forearm with a sterile skin punch (2-5 millimeters) or at incision site of muscle biopsy. Site is sterilized with alcohol swabs only (other reagents will inhibit cell isolation/growth). Biopsy site may be anaesthetized with 2% lidocaine with epinephrine. Depth of punch is 2mm. Transfer skin biopsy into 15 milliliter conical tube filled with sterile culture media. (6) Buccal cells.|
|Shipping Condition:||MNG SmartKits are available for free shipping of specimens. Please see our website for details. If you are not using a MNG SmartKit: (1) Blood specimens should be shipped in a secure container at room temperature. (2) Extracted DNA should be shipped priority overnight at ambient temperature. (3) T-25 flasks containing fibroblasts should be shipped in an insulated container at room temperature. Flasks should be completely filled with media and cells should be ~90% confluent. Fibroblast samples must be certified free from Mycoplasma. MNG is able to perform this service for a small charge (See TC05). (4) Muscle samples should be shipped frozen in an insulated container with 5-7 lbs dry ice. (5) Buccal cells should be shipped in a secure container at room temperature. (6) Skin Biopsy: Conical containing the skin specimen should be shipped in a secure container with cold pack (DO NOT FREEZE). All samples should be shipped overnight at the proper temperature for receipt by our lab Monday thru Saturday (No Sunday or holiday deliveries accepted).|