Tag: asystole
Sorry for not posting much lately, folks! I guess I’ve just been too busy…! Anyway, hope you like this one. It was brought to me by a colleague who thought I might enjoy it. He was perfectly right about that!
The patient: Elderly male, admitted to the CCU for near syncopes and episodic dizziness. He had a known atrial flutter, and was using betablockers and flecainide. I’m afraid I do not have the full list here, nor the dosages. He was sleeping when this episode occured and didn’t notice anything. He also did not pass out.
EKG description: This is atrial flutter (type 1, counter-clockwise) at approx. 260 bpm, with a high and quite varied degree of atrioventricular block. The lowest F-wave/QRS ratio in the top strip, is 4:1, resulting in a ventricular rate of around 65 bpm. Medications might play a part here, but one would suspect the ratio to be lower at this atrial rate. The long blocked period shows ventricular standstill that lasts for almost 6 seconds. This is of course the reason for his episodic dizziness and near syncopes (I’m surprised he didn’t syncope completely). In the lower strip, the blocked periods get even longer, practically resulting in ventricular standstill. With such persisting absence of AV conduction, normally one would expect a ventricular ectopic focus to take over. This however, did not happen here.
Conclusively, this is atrial flutter with a high-degree atrioventricular block and intermittent episodes ventricular standstill. The patophysiology behind this could be AV-node tissue degeneration over time, leading to progressively increasing level of block.
December 16, 2009
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Patient: n/a
ECG discussion: The top strip starts with sinus rhythm at ca. 75 bpm. Note that this generates a mean arterial pressure (MAP) of only 18 mmHg. A marked horizontal ST depression is also seen, which correlates with the pleth signal showing SpO2 of 74%. After 8 beats, there is no visible sinus activity any longer. No junctional escape rhythm is initiated, which indicates that the atrioventricular junction is also poorly perfused and suffering. The following beats are wide and slow, at only 35 bpm. Even though they resemble a ventricular/Purkinje escape rhythm by their morphology and regularity, this electrical activity is not able to create myocardial contraction. In the second strip, MAP is 13 and flatlined. This is explained electrophysiologically as electromechanical dissociation (EMD), which is similar to the term pulseless electrical activity (PEA).
The final (bottom) strip shows how the electrical activity ceases. Although mechanical asystole probably has happened already (hard to say without echocardiography), electric asystole has now also occured. Note that at the end of the strip the pleth wave is also flat.
September 8, 2009
The prehospital ECG obtained in the patient's home, the moment before cardiac arrest. Click image for full scale version (will open in a new window)
Patient: Male 90 y/o. Previous medical history unknown. Sudden onset of chest pain and severe dyspnea in his home. EMS responds quickly and this ECG is obtained in home. The ECG shows an AV junctional rhythm in the bradycardic range. The patient is awake but in severe pain. During transport to the hospital, the patient goes into full cardiac arrest. ACLS is started and is continued during transport to the ER. On arrival in the ER, ACLS continues. The patient is pulseless, with agonal respiration. After a total of one hour of ACLS without result, the resuscitation attempt is called off.
These strips are obtained in the ER from the defibrillator pads and show the progression from Pulseless Electrical Activity (PEA) into a flatline on the monitor. Note: PEA is also sometimes referred to as Electromechanical Dissociation (EMD), which is perhaps a more precise description of the electrophysiologic phenomenon that occurs. EMD is simply the term for when electrical activity occurs in the myocardium, but fails in depolarizing the cells and causing contraction of the heart muscle. This means that PEA/EMD is an agonal rhythm, and that PEA per definition is equal to asystole. However, when people say asystole, they usually refer to a flat line on the monitor/ECG. The next strips show the progression from PEA/EMD into a flat line.
First strip show chest compressions at a rate of ca. 140 bpm, followed by a rhythm check that displays an agonal rhythm/PEA. Compressions then start again. The next strips are recorded from the defibrillator during the next minutes and show the gradual morphologic progression from PEA into what is commonly referred to as flatline.
June 1, 2009