Torsades de Pointes

Why is Torsades everyone's favorite arrhythmia? Maybe because if you see it once and you will never forget it? Because IV Magnesium can provide dramatic reversal of the arrhythmia right before your eyes? Because the algorithm is so easy to remember? Let's look at it in a little more detail.... Torsades de Pointes, translated as "twisting of the spikes," is an irregular polymorphic wide complex tachycardia typically caused by one of two things. Most commonly it is triggered from prolonged QT syndrome. Prolonged QT is exacerbated by hypokalemia and hypomagnesemia as well as many medications, including some antiarrhythmics. When a PVC takes place during the relative refractory period between the QRS wave and T wave in the EKG, ventricular tachycardias can result. In the case of Torsades, the treatment of choice is Magnesium Sulfate, 1 to 2 grams IV. Another potential cause of Torsades is ischemia. In this instance, IV Magnesium will have no effect, and the ischemia will need to be reversed. (Cath Lab!) IV Magnesium probably will do no harm, and is still the initial treatment per the algorithm. When a patient presents with Torsades, an old EKG showing a previous prolonged QT would be one way to differentiate between the potential underlying cause of the disorder.

Generally "stable" Torsades is uncommon, and the rhythm tends to deteriorate quickly to VF. If electricity becomes necessary due to lack of Magnesium availability and patient instability, most likely synchronized cardioversion will be impossible due to the constantly changing nature of the rhythm, and higher difibrillation doses will be needed, unsynchronized. The rhythm is more common in white women and in patients with severe nutritional deficiencies, such as chronic alcoholics, and thus IV Magnesium could be considered as "treating the underlying cause."

Is the patient stable?

The ACLS algorithms for bradycardia and tachycardia essentially start the same way. In a nutshell, place the patient on a monitor, establish IV, apply oxygen. You can obtain a 12 lead ekg if you have time (if the patient is stable, but don’t delay therapy.) The next box in the algorithm essentially defines stability. Does the patient have persistent chest pain likely casued by ischemia, is the patient hypotensive (typically a blood pressure less than 90 WITH SYMPTOMS, in other words, are there signs of shock, altered mental status, etc? Is the patient in acute heart failure? Stability is different than "symptomatic." A patient who is generally stable may be symptomatic- orthostatic hypotension, mild shortness of breath, mild discomfort , palpitations. These are all signs that the patient may be symptomatic, (or feel the arrhythmia), but they are not overt signs of instability. For the symptomatic patient, it may be prudent to monitor, observe, and obtain expert consultation. For the unstable patient, the prudent course of action is to act. Generally, the fastest course of action for the truly unstable patient is going to be electricity, either pacing, or cardioversion, depending on the algorithm. Drugs have their place as well, and can be effective. the point is not to delay definitive therapy in the unstable patient. Check out more posts at: http://www.carpentercprsolutions.com/-blog.html or check us out on facebook: https://www.facebook.com/Carpentercprsolutions

Supra Ventricular Tachycardia versus true Ventricular Tachycardia...

I am often asked how to differentiate between SVT with abberrancy (wide complex supra-ventricular tachycardia) from a true ventricular tachycardia, which is important to decipher the appropriate treatment, and the severity of the arrhythmia. a nice, easy way is the following: "In 2010 Joseph Brugada et al. published a new criterion to differentiate VT from SVT in wide complex tachycardias: the R wave peak time in Lead II [4]. They suggest measuring the duration of onset of the QRS to the first change in polarity (either nadir Q or peak R) in lead II. If the RWPT is ≥ 50ms the likelihood of a VT very high (positive likelihood ratio 34.8). This criterion was successful in their own population of 163 selected patients and is awaiting prospective testing in a larger trial. " In other words, if the beginning of the QRS and the peak of the complex (or trough of a downward deflecting wave) in lead II is more than 0.05 seconds, the chances are very high that you are dealing with ventricular tachycardia. If you will recall, each small box on a strip equals 0.04 of a second, or 40 milliseconds. Source: http://www.heartrhythmjournal.com/article/S1547-5271%2810%2900216-X/abstract

Heatstroke

In honor of summer, how about a quick discussion of heat related emergencies..... There are a few types of heat crises that need first aid. The cause is the same, too much exposure to hot weather for too long, probably doing too much work with too little to drink. Heat emergencies exist on a continuum, from not very severe, to immediately life threatening. First comes heat exhaustion, common from exposure to hot, humid environments in particular. signs include moist, pale, clammy skin, hefty sweating, usual body temperature, dizziness, annoyance and irritation, nausea and potentially vomiting, muscle cramps, and even fainting. The treatment is generally simple: move the person to a cooler environment, offer small, frequent amounts of cool fluids, remove excess clothing, and provide cool towels and rest. If the patient is not improving or continues to vomit, get further medical treatment. Heatstroke is at the far end of the spectrum. Heatstroke is a potentially life-threatening emergency with the hallmark sign of markedly increased body temperature, potentially above 106 degrees Fahrenheit. The victim may have, warm, dry skin; tachycardia, and unconsciousness. This patient requires 911 and immediate advanced intervention. First Aid would involve calling 911, have the person lie down if possible, get clothes off, and start lowering the body temperature immediately by any means necessary. (The AHA video shows a couple of guys holding the heatstroke victim in a pool submerged to the chest. Bonus points for creativity.) Hosing the person down and applying ice packs would certainly be appropriate.