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Tachycardia: Difference between revisions
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→Ventricular tachycardia
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==Ventricular tachycardia== | ==Ventricular tachycardia== | ||
Ventricular tachycardia (VT) is defined as a sequence of three or more ventricular beats. The | Ventricular tachycardia (VT) is defined as a sequence of three or more ventricular beats. The rate is between 110-250 bpm. Ventricular tachycardias often origin around old scar tissue in the heart, e.g. after myocardial infarction. Also electrolyte disturbances and ischemia can cause ventricular tachycardias. The cardiac output is often strongly reduced during VT resulting in hypotension and loss of consciousness. VT is a medical emergency as it can deteriorate into ventricular fibrillation and thus mechanical cardiac arrest. | ||
===Definitions=== | ===Definitions=== | ||
* | *Non-sustained VT: three or more ventricular beats with a maximal duration of 30 seconds. | ||
* | *Sustained VT: a VT of more than 30 seconds duration (or less if treated by electrocardioversion within 30 seconds). | ||
* | *Monomorphic VT: all ventricular beats have the same configuration. | ||
* | *Polymorphic VT: the ventricular beats have a changing configuration. The heart rate is 100-333 bpm. | ||
* | *Biphasic VT: a ventricular tachycardia with a QRS complex that alternates from beat to beat. Associated with digoxin intoxication and long QT syndrome. | ||
===Localisation of the origin of a ventricular tachycardia=== | ===Localisation of the origin of a ventricular tachycardia=== | ||
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===Differential diagnosis=== | ===Differential diagnosis=== | ||
(Non)sustained VT may be idiopathic, but occurs most frequently in patients with underlying structural heart disease of various types including: | (Non)sustained VT may be idiopathic, but occurs most frequently in patients with underlying structural heart disease of various types including: | ||
*Coronary heart disease (CHD) with prior myocardial infarction | *Coronary heart disease (CHD) with prior myocardial infarction. This is the most frequent cause in developed countries | ||
*Hypertrophic cardiomyopathy | *Hypertrophic cardiomyopathy | ||
*Dilated cardiomyopathy | *Dilated cardiomyopathy | ||
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*Complex congenital heart disease | *Complex congenital heart disease | ||
*Cardiac sarcoidosis | *Cardiac sarcoidosis | ||
*Arrhythmogenic RV cardiomyopathy/dysplasia | *Arrhythmogenic RV cardiomyopathy/dysplasia | ||
If no structural heart disease is present the differential diagnosis includes: | |||
*Electrolyte disorders, especially hyper- / hypokalemia\ | |||
*Drugs: e.g. digoxin | |||
*Channelopathies (e.g. long QT syndrome, Brugada syndrome, CPVT) | |||
*Idiopathic ventricular tachycardia (e.g. RVOT tachycardia, idiopathic left ventricular tachycardia) | |||
*Purkinje VT’s (e.g. Belhassen) | |||
===Treatment=== | ===Treatment=== | ||
Hemodynamical instability: | |||
*Electrocardioversion | *Electrocardioversion | ||
Haemodynamical stability in a regular monomorphic broadcomplex tachycardia (systolic blood pressure >100 mmHg): | |||
*Pharmacological treatment can be considered with Procaïnamide or Amiodaron | *Pharmacological treatment can be considered with Procaïnamide or Amiodaron | ||
==Ventricular flutter== | ==Ventricular flutter== | ||