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Dawn's picture

Instructors' Collection ECG: Wide Complex Tachycardia

The Patient:   A 78-year-old woman called emergency responders because she had palpitations. She was alert and oriented.  Her BP was reported as being “stable”.  We do not have information about her past medical history.  We will update this post if we receive information about her outcome. 

ECG Number 1, 11:57 a.m.:  There is a wide-complex tachycardia at a rate of about 230 bpm.  The QRS is .15 seconds (150 ms).  The QRS frontal plane axis is leftward. P waves are not readily seen, but the computer gives a P axis and PRI.  The PRI given is taken from Lead II, which, along with V5, does have P waves. In the other leads, the P waves are buried in preceding T waves.  This photo shows an ECG that is not lying flat, so it is difficult to line up the complexes.  Normally, it helps to look at the leads above or below to determine where waves begin and end, as all three channels are run simultaneously. The QRS complexes have a “typical” left bundle branch block morphology, with an rS complex in V1 and a monophasic R wave in Leads I and V6.  The T waves are “discordant”, they are in the opposite direction from the QRS complexes, which is typical of LBBB. 

ECG Number 2, 12:05 p.m.:   This is a rhythm strip recording a synchronized shock at 100 joules, resulting in conversion of the WCT to a narrow complex, irregular rhythm.  It appears that there is a P wave before every narrow QRS, but artifact prevents proper evaluation. 

Dawn's picture

Regular Really Wide QRS Tachycardia

The Patient:    Unfortunately, this is an old tracing, and we do not have patient information, other than the list of medications the patient has been taking, (Lasix, Capoten, Ntg, and Procardia). Lasix (furosemide) is a potassium – wasting diuretic.  Capoten (captopril) is an ACE inhibitor.  Ntg is presumably sublingual nitroglycerine used for angina. Procardia (nifedipine) is a calcium-channel blocker.  So, we can assume the patient was probably being treated for angina, heart failure, and hypertension.

 The ECGThe first impression is that is a regular WIDE COMPLEX TACHYCARDIA.  The ventricular rate is 100 bpm (Starts a little faster at the beginning at 106, then is 100 by the end).  The QRS duration is about 250 ms (.25 seconds) – VERY WIDE.  There appear to be P waves outside the QRS complexes in V1 and aVL, but probably buried in the ST-T of other leads. 

 We were all taught to treat all wide complex tachycardia (WCT) as VENTRICULAR TACHYCARDIA (VT) until proven otherwise.  This is a very good rule, especially in an emergency setting. It pays to take a moment to consider the possibility of REGULAR REALLY WIDE COMPLEX TACHYCARDIA (RRWCT) before making a treatment decision.

 An extremely wide QRS can occur because of a number of very concerning reasons, most involving blockade of the sodium channels.  Included in this category are:

Dr A Röschl's picture

VENTRICULAR TACHYCARDIA WITH SUCCESSFUL ATP

If ventricular tachycardia occurs in an Implantable Cardioverter Defibrillator (ICD) wearer, the ICD can combat this with 2 different forms of therapy, provided these are activated (which can be done using a programming device). First, the ICD attempts to override the tachycardia. The fastest pacemaker gets control of the heart. If this is not successful, the defibrillator function is used. Here you can see the limb leads. Initially there is a relatively slow ventricular tachycardia.

Dr A Röschl's picture

SUSTAINED VENTRICULAR TACHYCARDIA

A sustained VT is a ventricular rhythm with a frequency of more than 100 beats per minute that usually lasts at least 30 seconds or must be terminated earlier due to hemodynamic instability.
We see here a wide complex tachycardia with a frequency of approx. 105-110 beats per minute that lasts for a good minute. It begins with a premature QRS complex without a premature P wave. The short VT after the end of the sustained ventricular tachycardia with the same QRS morphology also indicates a ventricular origin of this arrhythmia.

Dr A Röschl's picture

Ventricular Tachycardia. Unsuccessful Antitachycardia Pacing in an ICD Patient

If ventricular tachycardia occurs in an Implantable Cardioverter Defibrillator (ICD) wearer, the ICD can combat this with 2 different forms of therapy, provided these are activated (which can be done using a programming device). First, the ICD attempts to override the tachycardia. The fastest pacemaker gets control of the heart. If this is not successful, the defibrillator function is used. Here you can see the limb leads. Initially there is a relatively slow ventricular tachycardia with a heart rate of approx. 125 bpm.

Dr A Röschl's picture

Ventricular Tachycardia

There are several differential diagnoses in the presence of broad-complex tachycardia. The most common cause of wide-complex tachycardia is ventricular tachycardia. In 2nd place is sinus tachycardia/supraventricular tachycardia with aberrant conduction or preexisting bundle branch block.

Dr A Röschl's picture

WHY IS THIS VT

The tachycardia starts with a premature broad QRS complex. We see nonconducted sinus P waves. There are more QRS complexes than P waves, so it is AV-dissociation. There is no doubt that there is a VT present here.

Dr A Röschl's picture

Ventricular Tachycardia In A Patient With CAD And An Old Inferior M.I.

Broad complex tachycardia in a 78-year-old patient with coronary heart disease (CHD) and an old inferior myocardial infarction. Why is this a ventricular tachycardia (VT) and not a supraventricular tachycardia (SVT) with aberrant conduction? Broad complex tachycardia is generally about 80% likely to be ventricular in origin. However, in a patient with CHD and a history of myocardial infarction, this likelihood increases to about 90%. What other clues are there? The tachycardia initiates with a premature QRS complex without a preceding/premature P-wave.

Dr A Röschl's picture

VT or SVT? Here, Both!

Complex ECGs like this one have to be approached systematically. Firstly, we can see a normal sinus rhythm. A is the first beat of a wide complex tachycardia. This must be a ventricular tachycardia. Although there is a P-wave before the first beat of the tachycardia, it is not premature. Therefore, there is no SVT with aberrant conduction. The first beat of the tachycardia looks different from the subsequent beats because there is a fusion beat present. The VT conducts 1:1 back to the atria (a small negative P-wave can be seen at the end of the QRS complex in V1).

Dr A Röschl's picture

Ventricular Tachycardia After Inferior Myocardial Infarction

76-year-old man, with a history of inferior wall myocardial infarction. He experiences recurrent episodes of brief palpitations, often lasting only 5-15 seconds. In this ECG, at the beginning, the last part of a wide-complex tachycardia is visible. After 2 sinus beats, another wide-complex tachycardia begins (with the same QRS configuration).

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