Whether you're looking to brush up on your cardiology knowledge for daily practice or gearing up for the board exams, this post is tailored for you. This post dives into supraventricular arrhythmias, with a specific focus on atrial flutter.
In the video, Dr. Higgins presents a patient case involving a 76-year-old female with a history of atrial flutter. After initially being cardioverted to normal sinus rhythm, she experiences a recurrence of palpitations, fatigue, and exercise intolerance. Through this detailed case analysis, you'll gain valuable insights into the appropriate treatment options, including the use of catheter ablation for patients who fail to maintain sinus rhythm post-cardioversion.
This video not only prepares you for real-world scenarios but also equips you with the knowledge to excel in your board exams. By understanding the mechanisms, diagnosis, and management of atrial flutter, you can confidently address similar cases in your practice. Watch the video to delve deeper into the nuances of supraventricular arrhythmias and discover effective strategies for patient care.
This blog uses a snippet from our Internal Medicine Video Board Review lectures to refresh your knowledge on supraventricular arrhythmias to help you better prepare for both patient encounters and board exams.
This video is an excerpt from our 2024–2025 Internal Medicine Video Board Review. For a deeper review into Allergy & Immunology, plus 39+ more hours of board-focused lectures, explore our Video Board Review.
We’ve got a 76-year-old female who had atrial flutter 1 month ago. She was cardioverted to normal sinus rhythm—yay. She reports palpitations again—oh no—is fatigued, and cannot exercise. ECG today shows she’s back in the flutter. Her past medical [history] includes hypertension, HFpEF, diabetes, and hyperlipidemia. She’s on apixaban, metoprolol, lisinopril, metformin, rosuvastatin. The physical—you note an irregular pulse. The echo post cardioversion about a month ago showed an EF of 55%, left atrial dilation, and diastolic dysfunction.
So the question is now—she’s basically been cardioverted once, she’s back in it, and she’s not feeling great. What do you want to do? What is the most appropriate treatment?
Now, generally for the boards, just FYI, if you've got someone that's really, really symptomatic, “do nothing” is not gonna be the right answer.
Most of you have got that. So obviously, you know, “do nothing” and “cardiac catheterization” are distractors there. The question is—most of you got the catheter ablation—the question was, well, what about cardioverting again?
Most of these individuals— especially if they have echo abnormalities, like a dilated LV and diastolic dysfunction—if you cardiovert, she'll be back again in a month. So the boards want you essentially, this is, you try, always try people with a cardioversion once. You know, most of my patients, I will give them one cardioversion.
But if they've got structural heart disease and they go back into it, generally, it's time to think about other things. And catheter ablation is the one to think about with them.
So we're talking about typical or Type 1 atrial flutter in most of these individuals. So the atria is going wrong at about 300 beats per minute. And the ventricles—it's a tachycardia—so generally they're gonna be at, you know, uncontrolled, 100–150.
Now what this Type 1 is, it is a counter clockwise circuit in the right atrium. So it's going around like this about 3 or 4 times per second. So the inferior leads, you know, the ones down the legs, half the time they're gonna see a wave coming toward them, and then half the time it's gonna be going away from them.
Remember a positive toward a positive causes an upstroke on the ECG.
So the inferior leads in particular, you're gonna see this upstroke and then this, when it goes away, downstroke. So the inferior leads in particular are really, really good places to look for a flutter. And if you get 2 to 1 at a ventricle rate around 150, it's basically atrial flutter until proven otherwise, if it's an SVT. You can try to slow them down and get them to go to 3 to 1 or 4 to 1 by doing vagal or giving AV nodal blockers.
The main thing with A[trial] flutter is, just think from now on, I want you to think of A[trial] flutter and AFib as just one big blur. When we've done Holters, I can tell you so many people with flutter go into Fib and so many people with Fib go into flutter that literally many of the risk factors are similar—big atrium, diastolic dysfunction, poorly controlled blood pressure, etc. So think of them as AFib from that respect. So you should think about them also the same way, that is, rate control and then anticoagulation.
So in terms of someone who is acutely unstable, blast them. Zap them, or you can use pharmacological if they're hemodynamically stable. So one of the ones they sometimes use is ibutilide or dofetilide, and then get them on their meds.
With her, she was cardioverted and went on her meds, but now she's back into it. So, if they're symptomatic despite meds, so she's basically failed therapy, then we should refer her for catheter ablation, and it's 95% successful.
What they do in this catheter ablation is they put them in a flutter and they actually find that circuit—that cavotricuspid isthmus-dependent circuit—and they burn or freeze like 3 or 4, almost like fire breaks over that circuit. And so now the circuit can't start and it's very successful. So this is a great therapy that is used if they have failed.
Now AFib also involves circuits, but there are circuits going on all over the place in both atria, these little circuits and when they go off, each of these circuits, they do cause wavelets and you can see them, sometimes you can see them, you know, other times it's just kind of like this undulation here, but sometimes you can actually see them and they're called f waves because they're totally effed up.
No, they're fibrillatory—just seeing that you're still awake. Good!
Understanding and managing atrial flutter is important for Internal Medicine physicians to know—for boards and patient care. By delving into the intricacies of atrial flutter, from patient symptoms to effective treatments like catheter ablation, you are better equipped to handle such cases in your practice and succeed in your board exams.
By staying current with clinical guidelines and continually refreshing your knowledge with Internal Medicine Video Board Review, you can ensure that you are prepared to deliver the highest standard of care to your patients and take on any board exam.