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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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==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. | 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. | ||
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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 | ||