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Tachycardia: Difference between revisions
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''Sébastien Krul, MD, Louise Olde Nordkamp, MD, Jonas de Jong, MD'' | ''Sébastien Krul, MD, Louise Olde Nordkamp, MD, Jonas de Jong, MD'' | ||
==Introduction== | ==Introduction== | ||
[[Image:overview.png|thumb|300px|'''Figure 1.''' Classification of tachyarrhythmias.<cite>ECGPedia</cite>]] | [[Image:overview.png|thumb|300px|'''Figure 1.''' Classification of tachyarrhythmias.<cite>ECGPedia</cite>]] | ||
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==Ventricular flutter== | ==Ventricular flutter== | ||
Ventricular flutter is a ventricular tachycardia that occurs at a very rapid rate (often around 300 bpm), mostly caused by re-entry. The QRS complexes are regular and usually monomorphic and show a typical sinusoidal pattern. During ventricular flutter the ventricles depolarize in a circular pattern, which prevents good function. Most often this results in a minimal cardiac output and subsequent ischemia. Often deteriorates into ventricular fibrillation. | Ventricular flutter is a ventricular tachycardia that occurs at a very rapid rate (often around 300 bpm), mostly caused by re-entry. The QRS complexes are regular and usually monomorphic and show a typical sinusoidal pattern. During ventricular flutter the ventricles depolarize in a circular pattern, which prevents good function. Most often this results in a minimal cardiac output and subsequent ischemia. Often deteriorates into ventricular fibrillation. | ||
Treatment | |||
===Treatment=== | ===Treatment=== | ||
Electrocardioversion is the only treatment for ventricular flutter. | Electrocardioversion is the only treatment for ventricular flutter. | ||
==Ventricular fibrillation== | ==Ventricular fibrillation== | ||
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===Treatment=== | ===Treatment=== | ||
VF is lethal if the patient is not treated immediately. It gives rise to a mechanical standstill of the heart, because the heart is not able to pump normally anymore. Electrocardioversion is the only treatment for ventricular fibrillation. | VF is lethal if the patient is not treated immediately. It gives rise to a mechanical standstill of the heart, because the heart is not able to pump normally anymore. Electrocardioversion is the only treatment for ventricular fibrillation. | ||
==Accelerated idio-ventricular rhythm== | ==Accelerated idio-ventricular rhythm== | ||
Accelerated idioventricular rhythm (AIVR) is a relatively benign form of ventricular tachycardia. It is (mostly) a regular repetitive ventricular rhythm rate around 60-120 bpm, but mostly 80-100. It is the result of an enhanced ectopic ventricular rhythm, which is faster than normal intrinsic ventricular escape rhythm (<40 bpm), but slower than ventricular tachycardia (over 100-120 bpm). It often occurs during reperfusion after a myocardial infarction. AIVR is not predictive marker for early VF; however, recent debate has started whether among patients with successfull coronary intervention, AIVR is a sign of ventricular dysfunction and therefore a slightly worse prognosis. AIVR can also occur in infants. By this definition, this is a ventricular rhythm of no more than 20% faster than the sinus rate and occuring in the absence of other heart disease. This arrhythmia typically resolves spontaneously during the first months of life (in contrast to an infant with incessant VT which can be due to discrete myocardial tumors or congenital cardiomyopathy). | Accelerated idioventricular rhythm (AIVR) is a relatively benign form of ventricular tachycardia. It is (mostly) a regular repetitive ventricular rhythm with a rate around 60-120 bpm, but mostly 80-100. It is the result of an enhanced ectopic ventricular rhythm, which is faster than normal intrinsic ventricular escape rhythm (<40 bpm), but slower than ventricular tachycardia (over 100-120 bpm). It often occurs during reperfusion after a myocardial infarction. AIVR is not predictive marker for early VF; however, recent debate has started whether among patients with successfull coronary intervention, AIVR is a sign of ventricular dysfunction and therefore a slightly worse prognosis. AIVR can also occur in infants. By this definition, this is a ventricular rhythm of no more than 20% faster than the sinus rate and occuring in the absence of other heart disease. This arrhythmia typically resolves spontaneously during the first months of life (in contrast to an infant with incessant VT which can be due to discrete myocardial tumors or congenital cardiomyopathy). | ||
===Treatment=== | ===Treatment=== | ||
AIVR is generally a transient, self-limiting rhythm and resolves as sinus rate surpasses the rate of AIVR. It rarely causes hemodynamic instability and rarely requires treatment. | AIVR is generally a transient, self-limiting rhythm and resolves as sinus rate surpasses the rate of AIVR. It rarely causes hemodynamic instability and rarely requires treatment. | ||
==Torsades de Pointes== | ==Torsades de Pointes== | ||
[[Image: | [[Image:Torsade_de_Pointes.png|thumb|400px|Torsade de Pointes, preceded by bigemini.]] | ||
Torsade de pointes (TdP) is a ventricular tachycardia associated with a prolonged QTc interval on the resting ECG. The ECG is characterized by twisting of the peaks of the QRS complexes around the isoelectric baseline during the arrhythmia (changing axis). Torsade de pointes is initiated by a short-long-short interval. A ventricle extrasystole (first beat: short) is followed by a compensatory pause. The following beat (second beat: long) has a longer QT interval. If the next beat follows shortly thereafter, there is a good chance that this third beat falls within the QT interval, resulting in the R on T phenomenon and subsequent Torsades de pointes. | |||
=== | ===Causes of Torsade de Pointes=== | ||
*Aquired long QT syndrome (complete list of drugs causing long QT syndrome: | *Aquired long QT syndrome (complete list of drugs causing long QT syndrome: http://www.torsades.org http://www.torsades.org]) | ||
*Congenital long QT syndrome | *Congenital long QT syndrome | ||
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===Treatment=== | ===Treatment=== | ||
Electrocardioversion is the first treatment for TdP. | Electrocardioversion is the first treatment for TdP. | ||
Additional treatments are: | Additional treatments are: | ||
*Withdrawal of any offending drugs and correction of electrolyte abnormalities (potassium repletion up to 4.5 to 5 mmol/liter). | *Withdrawal of any offending drugs and correction of electrolyte abnormalities (potassium repletion up to 4.5 to 5 mmol/liter). | ||
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==Differentiation between SVT and VT== | ==Differentiation between SVT and VT== | ||
To differentiate between supraventricular tachycardias and ventricular tachycardias a 12 lead ECG is the cornerstone of the diagnostic process. At first, the physician has to make a differentiation between a | To differentiate between supraventricular tachycardias and ventricular tachycardias a 12 lead ECG is the cornerstone of the diagnostic process. At first, the physician has to make a differentiation between a narrow or wide complex tachycardia. | ||
===Definitions=== | ===Definitions=== | ||
'''Narrow complex tachycardia:''' QRS duration < 120 ms. | |||
A narrow complex tachycardia is most likely to be a SVT. However, also a septal VT or His-tachycardia can appear as a narrow complex tachycardia. | A narrow complex tachycardia is most likely to be a SVT. However, also a septal VT or His-tachycardia can appear as a narrow complex tachycardia. | ||
'''Wide complex tachycardia:''' QRS duration > 120 ms. | |||
A wide complex tachycardia can be due to a SVT with aberration, pre-exited tachycardia (eg antidrome re-entry tachycardia) or VT. | |||
A wide complex tachycardia can be due to a SVT with aberration, pre-exited tachycardia (eg antidrome re-entry tachycardia) or VT. | |||
===Differentiation=== | ===Differentiation=== | ||
These are the flow charts of a small and wide complex tachycardia to differentiate between the different rhythms: | These are the flow charts of a small and wide complex tachycardia to differentiate between the different rhythms: | ||
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===Treatment=== | ===Treatment=== | ||
'''Haemodynamical | '''Haemodynamical instability (systolic blood pressure less than 100 mmHg):''' | ||
* | *electrical cardioversion | ||
''' | '''Haemodynamical stability in a regular small complex tachycardia:''' | ||
*Carotid massage (after palpation and ausculatation of carotid arteries for exclusion of carotid occlusion/stenosis) | *Carotid massage (after palpation and ausculatation of carotid arteries for exclusion of carotid occlusion/stenosis) | ||
*Vasalva manoeuvre | *Vasalva manoeuvre | ||