• Well appearing;
• Eating regular diet;
• Normal glucose levels on admission;
• EKG QTc <480 msec.

Admit to ICU if:

• New diagnosis;
• Ill appearing or obtunded;
• Not tolerating oral diet;
• Hypoglycemia;
• EKG QTc ≥480 msec.

• IV fluids w/dextrose
• Echocardiogram to assess cardiac function
• Adjust IV fluid rate to avoid pulmonary edema; if normal cardiac function, IV fluids at 1.5-2x maintenance rate

• Treat as necessary to maintain normal potassium.
• Maintain serum Mg >2.2 mg/dL w/oral or IV Mg supplements.

• Vitamin supplementation is critical, especially folate (vitamin B₉) & pantothenic acid (vitamin B₅).
• Administer vitamins via NGT, IV, or TPN if not tolerating PO.
• IV fluids w/dextrose alone will not reverse rhabdomyolysis; nutritional support has been shown to ↓ CK levels.
• Acute kidney injury & complications from rhabdomyolysis are rare.

• Obtain EKG to assess QTc & presence of Brugada pattern. Daily EKG to monitor QTc & assess for presence of Brugada pattern. Continue daily EKG until steady downward trend in serum CK; if QTc becomes >480 msec, transfer to ICU.
• IV Mg supplementation to maintain serum Mg >2.2 mg/dL. If QTc is <480 msec, then maintain Mg levels >2.2 mg/dL using oral or intermittent IV supplements. If QTc is >480 msec, then replace Mg using continuous IV.
• Continuous rhythm monitoring to assess for PVCs & arrhythmias, particularly VT. Transfer to ICU if any premature ventricular contractions are noted.
• Obtain echocardiogram to assess function & adjust IVF rate based on cardiac function. Repeat echocardiogram every 3 days; echocardiogram less frequently after downward trend in serum CK; echocardiogram prior to discharge.
• Multivitamin supplementation upon admission incl all 8 B vitamins (minimum RDA for age); can be given in IV fluids until oral assessment completed.
• Monitor oral intake. Nutritional support (oral, NGT, or TPN) can prevent evolving cardiac crisis; most sick persons do not consume enough by oral diet.
• Ensure access to ICU w/ECMO in case of recalcitrant arrhythmia.

• Use of continuous monitoring leads in the high precordial placement can be helpful to visualize the intermittent development of a type I Brugada pattern.
• Avoid QT-prolonging drugs.

• Immediate transfer to ICU
• Continuous IV Mg to maintain serum Mg >2.2 mg/dL
• Keep isoproterenol bolus (0.03-0.05 µg/kg) at bedside.
• Consider isoproterenol infusion at 0.01-1 µg/kg/min. Titrate to maintain heart rates that suppress ectopy.
• IV multivitamin supplement incl all 8 B vitamins

• PVCs are harbingers of VT, which can develop rapidly once PVCs are noted.
• Beta-adrenergic blockers have not been shown to be consistently effective. VT tends to occur at lower heart rates, & hence avoiding beta-adrenergic blockers should be strongly considered.
• Avoid QT-prolonging drugs during crisis.
• Avoid sodium channel blockers (e.g., lidocaine, procainamide, amiodarone)

• Continuous bedside rhythm monitoring
• Direct current cardioversion is acutely effective, but VT/VF is often recurrent & recalcitrant.
• Administer isoproterenol bolus (0.03-0.05 µg/kg) & repeat if necessary.
• Continuous isoproterenol infusion at 0.01-1 µg/kg/min. Titrate to maintain heart rates that suppress ectopy. VT tends to occur more frequently at lower heart rates.
• IV multivitamin supplement incl all 8 B vitamins.
• Consider 1 g IV folate (B₉).
• In those w/ICD w/atrial lead, use atrial pacing at rates faster than sinus. Be cautious of development of tachycardia-induced cardiomyopathy.
• If TdPs continues despite first-line approaches, consider pacing using temporary esophageal pacing lead or ventricular lead.
• If VT/TdPs is recalcitrant, have ECMO treatment available.

• Temporary or surgical sympathetic denervation can be considered for recalcitrant VT.
• Consider IV calcium channel blocker.
• Consider avoiding beta-adrenergic blockers.
• Avoid sodium channel blockers (e.g., lidocaine, procainamide, amiodarone).
• VT is extremely difficult to manage in persons w/TANGO2 deficiency. VT is often unresponsive to standard therapies; in addition, standard therapies can make VT worse.

• Continue monitoring.
• Continue nutritional support & vitamin supplementation.
• Maintain Mg >2.2 mg/dL.
• Consider inotropic support that ↑ heart rate (see treatments for mildly to moderately depressed systolic function next)

• Isoproterenol can be given, but use w/caution for extended periods & monitor cardiac function closely.
• Atrial pacing can be used as an alternative to isoproterenol. ²
• If inotropic support is required, one that ↑ heart rate such as epinephrine should be considered, as this may help minimize VT/TdPs

• Atrial pacing is preferred over ventricular pacing.
• A transesophageal lead can be used in an emergency or for short-term pacing until a temporary wire can be placed.

• Consider inotropic support that ↑ heart rate (epinephrine), which may potentially prevent arrhythmias. Be careful w/fluid resuscitation to avoid pulmonary edema.
• Consider ECMO, since full recovery has been shown when metabolic crisis resolves.

• Systolic dysfunction can develop rapidly.
• Pulseless electrical activity & cardiac shock leading to death have occurred despite treatment.

• Continue Mg as first-line treatment.
• Consider inotropic support that ↑ heart rate (epinephrine).