Bus Bites

Bus BitesCardiac ArrhythmiasTachycardic- Part 1

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In this podcastOverview of tachycardic arrhythmiasLook more in detail at the broad QRS complex arrhythmiasCauses Signs and symptomsWhat they look like on ECGManagement

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OverviewArrhythmiasArrhythmias

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Broad QRS complex arrhythmias

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Ventricular TachycardiaDefined as three or more ventricular extrasystoles in succession at a rate of >120bpmCausesCoronary heart disease- including acute MICardiomyopathiesSigns and symptomsCan be pulseless- indicates minimal cardiac outputSyncopePalpitations, chest painHaemodynamic compromise

Haemodynamic compromise- low BP, breathlessness, signs of heart failure5

Ventricular TachycardiaDistinguish VT from SVT with BBB--- very broad QRS (> 0.14 s)

Pulseless VT?

Immediate defibrillationHaemodynamically compromised?

Urgent DC CardioversionStable?

Lignocaine or amiodaronePatient is2

There are a few ways to distinguish VT from SVT with BBB and one of the most important ways is the very broad QRS complex of over 0.14s seen in VT

If pulseless then this is a shockable rhythym and so you MUST defib!6

Torsades de PointesArises when ventricular repolarization (QT interval) is greatly prolonged. Can degenerate into VF and cause death.CausesCongenitalAcquiredMIDrugsBradycardiaElectrolyte disturbancesSigns and symptomsPalpitations, dizziness and syncope.Often terminates spontaneously

Remember all the hyposAntiarrhythmic drugs (Sotalol, Amiodarone)Erthromycin

Amitriptyline

Congenital- may be trigger by stress, fear or physical excretion.Bradycardia- sinoatrial disease, atrioventricular (AV) blockElectrolyte disturbances- Hypokalaemia, Hypomagnesaemia, Hypocalcaemia

Symptoms- Nausea, pallor, cold sweats, shortness of breath and chest pain may occurWill reoccur unless the underlying cause is removed.Can cause sudden death!7

Torsades de PointesQRS amplitude varies and the QRS complexes appear to twist around the baselineManagementCorrect electrolyte imbalancesStop causative drugsIV magnesium (even if magnesium levels are normal)Be aware that defibrillation may be needed if VF occurs.

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ECG shows a bradycardia followed by an episode of tachcardia with variable QRS amplitude- torsades de points

Management- ABCD etc 8

Ventricular FibrillationProduces rapid, ineffective, uncoordinated movement of the ventricles, which therefore produce no pulse and no cardiac output.CausesMI/ischaemiaStructural heart diseaseLong QT syndrome (Torsades de Pointes)Signs and symptomsPatient will likely be unconscious and pulseless

Structural heart disease- Aortic stenosis, Hypertrophic cardiomyopathy, Dilated cardiomyopathy, Congenital heart disease (p. 633)9

Ventricular FibrillationDefibrillation and resuscitation!

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See the algorithm for ALS for drug administration.10

Supraventricular tachycardia with bundle branch blockCauses, symptoms and management are similar to SVT without BBB i.e. Treatment with adenosine

Please see the Part 2 podcast on narrow QRS complex tachycardic arrhythmias11

SummaryBroad QRS complex tachycardic arrhythmias.Most are ventricular in origin with the exception of SVT with BBB. Ventricular tachycardiaAssess patient; shockable if pulseless. May need DC cardioversion or lidocaine or amiodaroneTorsades de PointesRemove causes first, then magnesium is treatment of choiceVentricular fibrillationshockable!

Thank you for listening!

References

Creative Commons Attribution-NonCommercial-ShareAlike 2.0 License. Author; www.soil-net.com (accessed 12th March 2011). Image altered by Charlotte CliffordCreative commons Attribution-Share Alike 3.0 Unported License. Author; Glenlarson (accessed 12th March 2011)Creative commons Attribution-Share Alike 3.0 Unported License. Author; displaced (accessed 12th March 2011)Creative commons Attribution-Share Alike 3.0 Unported License. Author; Andersat (accessed 12th March 2011)Image altered by Charlotte Clifford

Arises when ventricular repolarization (QT interval) is greatly prolonged. Can degenerate into VF and cause death.CausesCongenital- Jervell-Lange-Nielsen and Romano-WardAcquiredMIDrugs- antiarrhythmic drugs (Sotalol, Amiodarone), Erythromycin, AmitriptylineBradycardiaElectrolyte disturbances- all the hyposSigns and symptomsPalpitations, dizziness and syncope.Is not usually sustained and terminates spontaneously

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