Symptomatic therapy consists of:
- Checking the potassium and magnesium balance.
In case of deficiencies, substitution to high-normal serum levels is recommended (Herold 2022).
- Indications for antiarrhythmic drugs are:
- increased risk of sudden cardiac death due to e.g. ventricular fibrillation
- complex VES in patients with limitation of left ventricular pump function or severe underlying myocardial disease (Herold 2022)
- symptomatic idiopathic VES (Muser 2021).
In patients with idiopathic VES, the indication for antiarrhythmic therapy is in the case of
- frequently occurring VES, i.e., > 15% of cardiac actions are VES
- echocardiographic evidence of left ventricular dysfunction
- Occurrence of warning arrhythmias, ie:
- Occurrence of volley-like VES with limitations in exercise capacity.
- occurrence of syncope (Braun 2022)
When these warning arrhythmias occur, there is always a risk of sudden cardiac death due to the onset of ventricular fibrillation (Braun 2022).
In these patients, the use of class I antiarrhythmic drugs or beta-blockers is indicated as a basic measure (Braun 2022).
Antiarrhythmics of 1st choice are beta-blockers without intrinsic sympathomimetic activity for patients with impaired pumping capacity and Z. n. myocardial infarction (Herold 2022).
- Calcium channel blockers:
If beta-blockers do not produce the desired outcome, therapy with non- dihydropyridine calcium channel blockers is indicated. Dosing should be at the lowest effective dose, except in patients with recent myocardial infarction or existing heart failure. Here, the maximum tolerated dose should be titrated (Muser 2021).
If therapeutic success cannot be achieved with both beta blockers and calcium channel blockers, therapy with sodium channel blockers such as flecainide or propafenone is recommended. However, sodium channel blockers are contraindicated in the presence of existing coronary artery disease, heart failure, or severe left ventricular hypertrophy (Muser 2021).
In patients with VES-induced cardiomyopathy , amiodarone has been shown to improve symptoms and left ventricular function (Muser 2021)
Class I antiarrhythmic drugs are contraindicated in patients with structural heart disease, e.g., heart failure, CHD, because they may worsen prognosis. Similarly, amiodarone and sotalol show no prognostic advantage, even leading to worsening of prognosis in patients with NYHA III . In all these cases, an implantable cardioverter- defibrillator (ICD) is recommended (Herold 2022).
- Checking digitalis levels:
Digitalis levels should be checked in digitized patients. The therapeutic serum level is
- Digoxin: generally 0.8 - 2.0 ng / ml, in heart failure 0.5 - 0.8 ng / ml
- Digitoxin: generally 9 - 30 ng / ml, in heart failure no data (Karow 2021).
- Calcium: Ca2+ enhances the effect of digitalis and thus promotes toxicity (Karow 2021)
- Potassium: Hyperkalemia increases the risk of AV block (Lemmer 2007).
Any digitalis intoxication can be treated as follows:
Immediate cessation of digitalis intake.
Promote elimination of digitalis by:
Antidote treatment with Fab antibody fragments such as DigiFab (Böhm 2000). Dosage:
- if the amount of digitalis is known: 80 mg of antidigoxin- Fab binds 1 mg of digoxin, so that the digoxin- level decreases by 1ng / ml and for digitoxin by 10 ng / ml (Flake 2021).
- If the amount of digitalis is unknown: bolus 160 mg as a short infusion in 5% glucose over 20 min, then 20 mg / h over 12 h (Flake 2021)
In case of recent intoxication e.g. suicidal intent:
- Detoxification measures in the form of:
- Gastric lavage for a time interval < 1 h.
- administration of activated charcoal
- in case of intoxication with digitoxin:
- additional use of exchange resins such as colestipol or colestyramine
- Hemoperfusion:
- however, does not work in case of intoxication with digoxin
- Hemodialysis and peritoneal dialysis are not suitable for glycoside elimination (Böhm 2000).
- Symptomatic therapy of digitalisin intoxication in the form of:
- temporary pacemaker
- Atropine for bradycardia (Herold 2022) Dosage: 1mg atropine i. v. (Böhm 2000)
- For ventricular extrasystoles, tachycardia and ventricular flutter use of:
- Magnesium 20 mval i. v. (2 mval = 1 mmol / l (Hartig 2004).
- Phenytoin 100 mg i. v.
- Lidocaine 100 mg i. v.
- defibrillation
- Cardioversion (Böhm 2000)