Get certified in ACLS for just $195.00.
To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video
Many Wide Complex Tachycardias originate in the ventricles but some do not. The one’s that do not may include aberrant SVT like a bundle branch block, or a ventricular reentry problem where the ventricles may contract too early after partial repolarization like that of a preexcited tachycardia or Wolff-Parkinson White syndrome. A very common V-Tach is called monomorphic ventricular tachycardia. This means that all of the complexes are the same size, direction and shape. This is usually caused by an ectopic pacemaker somewhere located in the ventricle. In this ECG, the rhythm is regular but may also be slightly irregular. The rate is around 1 to 200 beats per minute and there are rarely any discernable P-waves. There is no discernable PR interval and QRS complex is greater than .11 seconds and are characterized as wide and bizarre with no P-wave to QRS ratio. Now the main problem with this type of fast wide complex tachycardia is that hemodynamics are unstable. The heart rate is so fast, that it inhibits the atrium to prefill and preload the ventricles prior to their next contraction. In this case, it’s important to know if the patient is stable or unstable. If stable, learn more about why the patient may be experiencing this arrhythmia, remember, wide complex ventricular tachycardia can sometimes be caused by heart disease, electrolyte imbalance especially potassium, and Q-T interval prolongation. If patient is stable order a 12 lead ECG to see if the rhythm is supraventricular or ventricular in origin. If the patient is unstable, immediate treatment is vital. Now let’s look at Wide complex Polymorphic Ventricular Tachycardia. Poly, meaning multiple, describes the origin of the electrical foci in the ventricles well. In fact, Polymorphic tachycardia is caused by multiple ventricular foci with the resultant QRS complexes varying in axis, amplitude, and duration. It can also be described as Bidirectional V-Tach, which is another type of polymorphic ventricular tachycardia, most commonly associated with digoxin toxicity, and this is known commonly as Torsades de pointes. Along with digoxin toxicity, we can see polymorphic VT with hypomagnesemia and hypokalemia. Let’s take a closer look at the ECG for Polymorphic Wide Complex Tachycardia. The rhythm is irregular with a rate of between 200-250 beats per minute. There are no discernable P-waves and there is no PR interval. QRS complexes are variable but greater than .11 seconds and they’re wide and bizarre. There is no P-wave to QRS ratio. Now in Torsades, it can sometimes appear that the apex of the V-wave changes from top to bottom and back again. Torsade de pointes, or TDP, translates as “twisting of points.” The most important thing to remember with this type, and monomorphic wide complex V-Tach, is that both can become pulseless V-Tach or v-fib very quickly. It’s important to remember that Wide complex Ventricular Tachycardia can present with or without a pulse. We can even see pulseless V-Tach in cardiac arrest patients, but in most cases, pulseless V-Tach quickly deteriorates into Ventricular Fibrillation. Remember, Pulseless V-Tach is treated the same as Ventricular Fibrillation. And recognition and immediate treatment is vital to a potential positive outcome. The ECG interpretation can be the same as pulsed Ventricular Tachycardia, but the difference is that the patient is unresponsive, not breathing normally and pulseless.
Many wide complex tachycardias originate in the ventricles, but not all. The ones that don't include a bundle branch block, and a ventricular reentry problem, where the ventricles contract too early after a partial repolarization – like a pre-excited tachycardia or Wolff-Parkinson-White (WPW) syndrome.
In this lesson, we'll look at monomorphic ventricular tachycardia (including an ECG), polymorphic ventricular tachycardia, or (thankfully) PVT for short (also including an ECG), and pulseless ventricular tachycardia. And at the end of the lesson, we'll provide a Word about treatments based on the type of tachycardia.
One very common V-tach is called monomorphic ventricular tachycardia, which means that all of the complexes are the same size, direction, and shape. It's usually caused by an ectopic pacemaker located somewhere in the ventricles.
An ECG for a patient with monomorphic V-tach will exhibit the following signs.
*Monomorphic V-tach ECG for Pediatric Patient
The main problem with this type of fast and wide complex tachycardias is that the hemodynamics are unstable. The heart rate is so fast that it inhibits the atrium from prefilling and preloading the ventricles before the next contraction. In these cases, it's important to know whether or not the patient is stable or unstable.
Pro Tip #1: If the patient is stable, try to learn more about why the patient could be experiencing this type of arrhythmia. And remember, wide complex V-tach can sometimes be caused by heart disease, electrolyte imbalance (especially potassium) and a Q to T interval prolongation.
If the patient is stable, check to see if their rhythm is supraventricular or ventricular in origin.
Warning: If the patient is unstable, immediate treatment is vital.
Poly simply means multiple and describes the origin of electrical foci in the ventricles. In fact, polymorphic V-tach is caused by multiple ventricular foci with the resulting QRS complexes varying in axis, amplitude, and duration.
Polymorphic V-tach can also be described as bi-directional V-tach, which is another type of polymorphic V-tach that is commonly associated with digoxin toxicity, commonly known as torsades de pointes.
Along with digoxin toxicity, we often see polymorphic V-tach with hypokalemia or hypomagnesemia.
An ECG for a patient with polymorphic V-tach will exhibit the following signs.
* Polymorphic Ventricular Tachycardia ECG for Pediatric Patient
In torsades, it can sometimes appear that the apex of the V-wave changes from top to bottom and back again. And actually, torsades (French in origin) literally translates as a twisting of points.
The most important thing to remember with this type, along with monomorphic wide-complex V-tach, is that both can become pulseless V-tach or VFib pretty quickly.
Pro Tip #2: One important thing to remember is that wide complex V-tach can present with or without a pulse and you may even see pulseless V-tach in a cardiac arrest patient. However, in most cases, pulseless V-tach will quickly deteriorate into VFib.
Also keep in mind that pulseless V-tach is treated the same as VFib and that recognition of the condition and treatment for it will be vital for a potential positive outcome.
Pro Tip #3: An ECG interpretation for pulseless V-tach can be the same for pulsed V-tach. The difference is that the patient is unresponsive, not breathing normally, and has no pulse.
Distinguish between supraventricular and ventricular rhythms can be difficult. Most wide complex tachycardias are ventricular in origin, particularly if the patient is older or has underlying heart disease.
If the patient is pulseless, you should treat the rhythm as VFib and follow the cardiac arrest algorithm.
If the patient has a wide complex tachycardia and is also unstable, you should assume it's V-tach until proven wrong. The amount of energy required for cardioversion of V-tach is determined by the following morphologic characteristics.
1. If the patient is unstable but has a pulse with regular, uniform wide complex V-tach, or monomorphic V-tach:
2. Arrhythmias with a polymorphic QRS appearance, or polymorphic V-tach, such as torsades de pointes, will usually not permit synchronization. If the patient has polymorphic V-tach:
If there is any doubt about whether an unstable patient has monomorphic or polymorphic V-tach, don't delay treatment for further rhythm analysis. Instead, go right into providing high-energy, unsynchronized shocks.