{"version":"1.0.0","segments":[{"startTime":0.637,"endTime":3.305,"body":"♪ (music) ♪"},{"startTime":3.305,"endTime":5.687,"body":"(Cathy) Hi. Welcome"},{"startTime":3.305,"endTime":5.687,"body":"to \u003ci\u003eHarrison's Podclass,\u003c/i\u003e"},{"startTime":5.687,"endTime":8.735,"body":"where we discuss important concepts"},{"startTime":5.687,"endTime":8.735,"body":"in internal medicine."},{"startTime":8.735,"endTime":10.991,"body":"- I'm Cathy Handy."},{"startTime":8.735,"endTime":10.991,"body":"- (Charlie) And I'm Charlie Wiener,"},{"startTime":10.991,"endTime":14.11,"body":"and we're coming to you"},{"startTime":10.991,"endTime":14.11,"body":"from the Johns Hopkins School of Medicine."},{"startTime":16.003,"endTime":19.902,"body":"(Cathy) Welcome to Episode 16"},{"startTime":16.003,"endTime":19.902,"body":"of \u003ci\u003eA Young Woman Found Down.\u003c/i\u003e"},{"startTime":19.902,"endTime":21.175,"body":"(Charlie) Here's the question."},{"startTime":21.175,"endTime":23.561,"body":"A young woman is brought"},{"startTime":21.175,"endTime":23.561,"body":"to the emergency department"},{"startTime":23.561,"endTime":26.487,"body":"after witnesses observed her"},{"startTime":23.561,"endTime":26.487,"body":"suddenly lose consciousness,"},{"startTime":26.487,"endTime":29.044,"body":"while she was jogging"},{"startTime":26.487,"endTime":29.044,"body":"in the nearby park."},{"startTime":29.044,"endTime":32.651,"body":"She has a fractured nose"},{"startTime":29.044,"endTime":32.651,"body":"and broken teeth from her fall."},{"startTime":32.651,"endTime":34.722,"body":"She has no identification."},{"startTime":34.722,"endTime":37.583,"body":"She's awake, but she's confused."},{"startTime":37.583,"endTime":38.739,"body":"Her vitals are notable"},{"startTime":38.739,"endTime":41.555,"body":"for a blood pressure"},{"startTime":38.739,"endTime":41.555,"body":"of only 60 over palpable,"},{"startTime":41.555,"endTime":45.347,"body":"and her heart rate"},{"startTime":41.555,"endTime":45.347,"body":"is close to 280 beats/minute."},{"startTime":45.347,"endTime":48.761,"body":"Cathy, what do you think so far,"},{"startTime":45.347,"endTime":48.761,"body":"and what more do you want to know?"},{"startTime":48.761,"endTime":51.006,"body":"(Cathy) So, this is a case"},{"startTime":48.761,"endTime":51.006,"body":"of a young woman with syncope,"},{"startTime":51.006,"endTime":53.939,"body":"and we hear"},{"startTime":51.006,"endTime":53.939,"body":"that her heart rate is still 280."},{"startTime":53.939,"endTime":57.816,"body":"I know it's not sinus tachycardia"},{"startTime":53.939,"endTime":57.816,"body":"because the max predicted heart rate"},{"startTime":57.816,"endTime":59.567,"body":"that we would expect"},{"startTime":57.816,"endTime":59.567,"body":"with sinus tachycardia"},{"speaker":"comes from the formula","startTime":59.567,"endTime":63.065,"body":"220 minus age."},{"speaker":"comes from the formula","startTime":63.065,"endTime":65.377,"body":"We don't know her age,"},{"speaker":"comes from the formula","startTime":63.065,"endTime":65.377,"body":"but it doesn't matter anyways"},{"speaker":"comes from the formula","startTime":65.377,"endTime":68.734,"body":"because 280 is too high"},{"speaker":"comes from the formula","startTime":65.377,"endTime":68.734,"body":"for sinus tachycardia."},{"speaker":"comes from the formula","startTime":68.734,"endTime":70.473,"body":"Sounds like she was brought in by EMS,"},{"speaker":"comes from the formula","startTime":70.473,"endTime":73.701,"body":"so I assume we have an EKG"},{"speaker":"comes from the formula","startTime":70.473,"endTime":73.701,"body":"showing what her heart rhythm is."},{"speaker":"comes from the formula","startTime":73.701,"endTime":76.159,"body":"(Charlie) I'm looking at"},{"speaker":"comes from the formula","startTime":73.701,"endTime":76.159,"body":"her rhythm strip, and it shows me"},{"speaker":"comes from the formula","startTime":76.159,"endTime":81.012,"body":"that she has a wide complex,"},{"speaker":"comes from the formula","startTime":76.159,"endTime":81.012,"body":"irregularly irregular tachycardia,"},{"speaker":"comes from the formula","startTime":81.012,"endTime":85.126,"body":"with a rate that is approximately"},{"speaker":"comes from the formula","startTime":81.012,"endTime":85.126,"body":"250-300 beats/minute."},{"speaker":"comes from the formula","startTime":85.126,"endTime":86.525,"body":"How does that help you?"},{"speaker":"comes from the formula","startTime":86.525,"endTime":88.528,"body":"(Cathy) Well, when I'm thinking"},{"speaker":"comes from the formula","startTime":86.525,"endTime":88.528,"body":"about tachycardias,"},{"speaker":"comes from the formula","startTime":88.528,"endTime":90.134,"body":"and when we have time to think about it,"},{"speaker":"comes from the formula","startTime":90.134,"endTime":91.568,"body":"I first look to distinguish"},{"speaker":"comes from the formula","startTime":91.568,"endTime":95.809,"body":"whether it's a wide complex tachycardia"},{"speaker":"comes from the formula","startTime":91.568,"endTime":95.809,"body":"or a narrow complex tachycardia."},{"speaker":"comes from the formula","startTime":95.809,"endTime":99.022,"body":"Narrow complex tachycardias"},{"speaker":"comes from the formula","startTime":95.809,"endTime":99.022,"body":"are generally supraventricular"},{"speaker":"comes from the formula","startTime":99.022,"endTime":102.987,"body":"and wide complex tachycardias"},{"speaker":"comes from the formula","startTime":99.022,"endTime":102.987,"body":"are generally from the ventricle."},{"speaker":"comes from the formula","startTime":102.987,"endTime":105.967,"body":"(Charlie) But are all wide complex"},{"speaker":"comes from the formula","startTime":102.987,"endTime":105.967,"body":"tachycardias from the ventricle?"},{"speaker":"comes from the formula","startTime":105.967,"endTime":107.118,"body":"(Cathy) Definitely not all."},{"speaker":"comes from the formula","startTime":107.118,"endTime":109.16,"body":"So, most of the time they are,"},{"speaker":"comes from the formula","startTime":107.118,"endTime":109.16,"body":"and you want to know"},{"speaker":"comes from the formula","startTime":109.16,"endTime":111.788,"body":"if it's a ventricular"},{"speaker":"comes from the formula","startTime":109.16,"endTime":111.788,"body":"tachycardia right away."},{"speaker":"comes from the formula","startTime":111.788,"endTime":115.086,"body":"But supraventricular tachycardias"},{"speaker":"comes from the formula","startTime":111.788,"endTime":115.086,"body":"that do not go through the AV node"},{"speaker":"comes from the formula","startTime":115.086,"endTime":117.518,"body":"can give you a wide complex tachycardia."},{"speaker":"comes from the formula","startTime":117.518,"endTime":120.761,"body":"And also, if there's pre-existing"},{"speaker":"comes from the formula","startTime":117.518,"endTime":120.761,"body":"conduction system disease,"},{"speaker":"comes from the formula","startTime":120.761,"endTime":122.929,"body":"you can also get a wide complex."},{"speaker":"comes from the formula","startTime":122.929,"endTime":125.16,"body":"(Charlie) And when you say"},{"speaker":"comes from the formula","startTime":122.929,"endTime":125.16,"body":"\u003ci\u003epre-existing conduction disease,\u003c/i\u003e"},{"speaker":"comes from the formula","startTime":125.16,"endTime":127.067,"body":"you mean like a patient"},{"speaker":"comes from the formula","startTime":125.16,"endTime":127.067,"body":"with a bundle branch block"},{"speaker":"comes from the formula","startTime":127.067,"endTime":128.234,"body":"or something like that?"},{"speaker":"comes from the formula","startTime":128.234,"endTime":130.551,"body":"(Cathy) Yeah, absolutely."},{"speaker":"comes from the formula","startTime":128.234,"endTime":130.551,"body":"And that's common in older people"},{"speaker":"comes from the formula","startTime":130.551,"endTime":132.783,"body":"who have a history"},{"speaker":"comes from the formula","startTime":130.551,"endTime":132.783,"body":"of ischemic heart disease,"},{"speaker":"comes from the formula","startTime":132.783,"endTime":135.768,"body":"or if they have"},{"speaker":"comes from the formula","startTime":132.783,"endTime":135.768,"body":"an infiltrative cardiomyopathy."},{"speaker":"comes from the formula","startTime":135.768,"endTime":137.857,"body":"(Charlie) Okay. So, I mentioned"},{"speaker":"comes from the formula","startTime":135.768,"endTime":137.857,"body":"that this tachycardia"},{"speaker":"comes from the formula","startTime":137.857,"endTime":140.07,"body":"appeared to be irregularly irregular."},{"speaker":"comes from the formula","startTime":140.07,"endTime":141.512,"body":"How does that help you?"},{"speaker":"comes from the formula","startTime":141.512,"endTime":144.037,"body":"(Cathy) So, with an irregularly"},{"speaker":"comes from the formula","startTime":141.512,"endTime":144.037,"body":"irregular rhythm,"},{"speaker":"comes from the formula","startTime":144.037,"endTime":146.657,"body":"it's unlikely that"},{"speaker":"comes from the formula","startTime":144.037,"endTime":146.657,"body":"it's ventricular tachycardia,"},{"speaker":"comes from the formula","startTime":146.657,"endTime":148.709,"body":"because that usually has a regular rhythm."},{"speaker":"comes from the formula","startTime":148.709,"endTime":151.767,"body":"And it's not ventricular fibrillation,"},{"speaker":"comes from the formula","startTime":148.709,"endTime":151.767,"body":"because she's awake."},{"speaker":"comes from the formula","startTime":151.767,"endTime":156.387,"body":"So, we're thinking of supraventricular"},{"speaker":"comes from the formula","startTime":151.767,"endTime":156.387,"body":"rhythms that are irregularly irregular."},{"speaker":"comes from the formula","startTime":156.387,"endTime":158.658,"body":"So, there my sort of differential is,"},{"speaker":"comes from the formula","startTime":158.658,"endTime":162.765,"body":"is this atrial fibrillation"},{"speaker":"comes from the formula","startTime":158.658,"endTime":162.765,"body":"or is this multifocal atrial tachycardia?"},{"speaker":"comes from the formula","startTime":162.765,"endTime":165.303,"body":"And the way to distinguish"},{"speaker":"comes from the formula","startTime":162.765,"endTime":165.303,"body":"these are on ECG."},{"speaker":"comes from the formula","startTime":165.303,"endTime":168.339,"body":"If you think about MAT,"},{"speaker":"comes from the formula","startTime":165.303,"endTime":168.339,"body":"or multifocal atrial tachycardia,"},{"speaker":"comes from the formula","startTime":168.339,"endTime":170.524,"body":"you'll have different P wave morphologies."},{"speaker":"comes from the formula","startTime":170.524,"endTime":174.537,"body":"And in atrial fibrillation, you won't have"},{"speaker":"comes from the formula","startTime":170.524,"endTime":174.537,"body":"any recognizable P waves."},{"speaker":"comes from the formula","startTime":174.537,"endTime":178.173,"body":"(Charlie) Okay. So, I'm looking"},{"speaker":"comes from the formula","startTime":174.537,"endTime":178.173,"body":"at the ECG, and I see no P waves."},{"speaker":"comes from the formula","startTime":178.173,"endTime":181.088,"body":"Therefore, you think"},{"speaker":"comes from the formula","startTime":178.173,"endTime":181.088,"body":"it's likely atrial fibrillation"},{"speaker":"comes from the formula","startTime":181.088,"endTime":183.717,"body":"with antegrade conduction"},{"speaker":"comes from the formula","startTime":181.088,"endTime":183.717,"body":"through an accessory tract?"},{"speaker":"comes from the formula","startTime":183.717,"endTime":185.322,"body":"(Cathy) Yup. That's what I would think."},{"speaker":"comes from the formula","startTime":185.322,"endTime":187.08,"body":"(Charlie) Okay."},{"speaker":"comes from the formula","startTime":185.322,"endTime":187.08,"body":"Well, the question then asks,"},{"speaker":"comes from the formula","startTime":187.08,"endTime":189.228,"body":"What is the most appropriate next step?"},{"speaker":"And the options are","startTime":190.694,"endTime":192.718,"body":"a) amiodarone;"},{"speaker":"And the options are","startTime":192.718,"endTime":194.805,"body":"b) lidocaine;"},{"speaker":"And the options are","startTime":194.805,"endTime":197.099,"body":"c) metoprolol;"},{"speaker":"And the options are","startTime":197.099,"endTime":199.229,"body":"d) defibrillation;"},{"speaker":"And the options are","startTime":199.229,"endTime":203.951,"body":"or e) an emergent CT scan with contrast"},{"speaker":"And the options are","startTime":199.229,"endTime":203.951,"body":"to evaluate for pulmonary embolism."},{"speaker":"And the options are","startTime":203.961,"endTime":205.407,"body":"(Cathy) Well, the patient's unstable"},{"speaker":"And the options are","startTime":205.407,"endTime":208.144,"body":"with hypotension"},{"speaker":"And the options are","startTime":205.407,"endTime":208.144,"body":"and poor cerebral perfusion."},{"speaker":"And the options are","startTime":208.144,"endTime":212.036,"body":"And that, we suspect, is really"},{"speaker":"And the options are","startTime":208.144,"endTime":212.036,"body":"because of her wide complex tachycardia."},{"speaker":"And the options are","startTime":212.036,"endTime":214.995,"body":"So, defibrillation is really"},{"speaker":"And the options are","startTime":212.036,"endTime":214.995,"body":"the only therapy that's appropriate"},{"speaker":"And the options are","startTime":214.995,"endTime":217.507,"body":"and that should be performed"},{"speaker":"And the options are","startTime":214.995,"endTime":217.507,"body":"as soon as possible."},{"speaker":"And the options are","startTime":217.507,"endTime":219.794,"body":"Frankly, any tachycardia"},{"speaker":"And the options are","startTime":217.507,"endTime":219.794,"body":"with these symptoms,"},{"speaker":"And the options are","startTime":219.794,"endTime":221.121,"body":"you would want to defibrillate,"},{"speaker":"And the options are","startTime":221.121,"endTime":223.014,"body":"and you would save"},{"speaker":"And the options are","startTime":221.121,"endTime":223.014,"body":"any of the other measures"},{"speaker":"And the options are","startTime":223.014,"endTime":226.175,"body":"that you mentioned for more"},{"speaker":"And the options are","startTime":223.014,"endTime":226.175,"body":"non-emergent situations."},{"speaker":"And the options are","startTime":226.175,"endTime":228.038,"body":"(Charlie) What do you think"},{"speaker":"And the options are","startTime":226.175,"endTime":228.038,"body":"of those other options,"},{"speaker":"And the options are","startTime":228.038,"endTime":229.561,"body":"and where would they be useful?"},{"speaker":"And the options are","startTime":229.561,"endTime":233.231,"body":"(Cathy) So, if the patient were stable,"},{"speaker":"And the options are","startTime":229.561,"endTime":233.231,"body":"amiodarone or metoprolol could be used"},{"speaker":"And the options are","startTime":233.231,"endTime":237.499,"body":"in a patient with atrial fibrillation"},{"speaker":"And the options are","startTime":233.231,"endTime":237.499,"body":"with a rapid ventricular response."},{"speaker":"And the options are","startTime":237.499,"endTime":240.482,"body":"A CT scan for the etiology"},{"speaker":"And the options are","startTime":237.499,"endTime":240.482,"body":"could be reasonable"},{"speaker":"And the options are","startTime":240.482,"endTime":244.982,"body":"if you suspected pulmonary embolism"},{"speaker":"And the options are","startTime":240.482,"endTime":244.982,"body":"and if the patient had stable vital signs."},{"speaker":"And the options are","startTime":244.982,"endTime":247.4,"body":"Also, if PE was really"},{"speaker":"And the options are","startTime":244.982,"endTime":247.4,"body":"a strong consideration"},{"speaker":"And the options are","startTime":247.4,"endTime":248.796,"body":"and you couldn't get a CT scan,"},{"speaker":"And the options are","startTime":248.796,"endTime":251.857,"body":"you could always start"},{"speaker":"And the options are","startTime":248.796,"endTime":251.857,"body":"empiric anticoagulation."},{"speaker":"And the options are","startTime":251.867,"endTime":253.828,"body":"Lidocaine is used"},{"speaker":"And the options are","startTime":251.867,"endTime":253.828,"body":"for ventricular arrhythmias,"},{"speaker":"And the options are","startTime":253.828,"endTime":255.74,"body":"so I wouldn't use that in this setting."},{"speaker":"And the options are","startTime":255.74,"endTime":258.101,"body":"(Charlie) So, the teaching point"},{"speaker":"And the options are","startTime":255.74,"endTime":258.101,"body":"in this case, most notably,"},{"speaker":"And the options are","startTime":258.101,"endTime":261.655,"body":"is that, in any unstable patient"},{"speaker":"And the options are","startTime":258.101,"endTime":261.655,"body":"with a tachyarrhythmia,"},{"speaker":"And the options are","startTime":261.655,"endTime":264.026,"body":"DC cardioversion is the first step."},{"speaker":"And the options are","startTime":264.026,"endTime":267.785,"body":"Furthermore, the etiology"},{"speaker":"And the options are","startTime":264.026,"endTime":267.785,"body":"of the tachycardias may be distinguished"},{"speaker":"And the options are","startTime":267.785,"endTime":271.722,"body":"by their QRS morphology"},{"speaker":"And the options are","startTime":267.785,"endTime":271.722,"body":"and their regularity."},{"speaker":"And the options are","startTime":271.722,"endTime":273.664,"body":"(Cathy) And for more on this,"},{"speaker":"And the options are","startTime":271.722,"endTime":273.664,"body":"you can check out"},{"speaker":"And the options are","startTime":273.664,"endTime":275.146,"body":"\u003ci\u003eHarrison's\u003c/i\u003e Disorders of Rhythm"},{"speaker":"And the options are","startTime":275.146,"endTime":278.235,"body":"in the section on Disorders"},{"speaker":"And the options are","startTime":275.146,"endTime":278.235,"body":"of the Cardiovascular System."},{"speaker":"And the options are","startTime":278.235,"endTime":280.555,"body":"♪ (music) ♪"}]}