Episode 874: Bradyarrhythmias

<p dir="ltr"><strong>Contributor: Dylan Luyten MD</strong></p> <p dir="ltr"><strong>Educational Pearls:</strong></p> <p dir="ltr">What is a Bradyarrhythmia?</p> <ul> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Also known as a bradyarrhythmia, it is an irregular heart rate that is also slow (below 60 beats per minute).</p> </li> </ul> <p dir="ltr">What can cause it?</p> <ul> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Complete heart block AKA third-degree AV block; identified on ECG by a wide QRS, and complete dissociation between the atrial and ventricular rhythms with the ventricular being much slower. Treat with a pacemaker.</p> </li> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Medication overdose, especially beta blockers. Many other drugs can slow the heart as well including: opioids, clonidine, digitalis, amiodarone, diltiazem, and verapamil to name a few.</p> </li> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Electrolyte abnormalities, specifically hyperkalemia. Hypokalemia, hypocalcemia, and hypomagnesemia can also cause bradyarrhythmias.</p> </li> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Myocardial infarction. Either by damaging the AV node or the conduction system itself or by triggering a process called Reperfusion Bradycardia.</p> </li> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Hypothermia. Bradycardia is generally a sign of severe or advanced hypothermia.</p> </li> </ul> <p dir="ltr">References</p> <ol> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Jurkovicová O, Cagán S. Reperfúzne arytmie [Reperfusion arrhythmias]. Bratisl Lek Listy. 1998 Mar-Apr;99(3-4):162-71. Slovak. PMID: 9919746.</p> </li> <li dir="ltr" aria-level="1"> <p dir="ltr" role="presentation">Simmons T, Blazar E. Synergistic Bradycardia from Beta Blockers, Hyperkalemia, and Renal Failure. J Emerg Med. 2019 Aug;57(2):e41-e44. doi: 10.1016/j.jemermed.2019.03.039. Epub 2019 May 30. PMID: 31155316.</p> </li