Where do you see electrical alternans?
It is seen in cardiac tamponade and severe pericardial effusion and is thought to be related to changes in the ventricular electrical axis due to fluid in the pericardium, as the heart essentially wobbles in the fluid filled pericardial sac.
Why do you get electrical alternans?
A typical cause of electrical alternans is a pericardial effusion, and is due to periodic wobbling of the heart in the pericardium (1). However, alternating axis shift may be due not to mechanical shifting of the heart, but to alternating conduction abnormality, such as intermittent fascicular or bundle branch block.
Why does cardiac tamponade cause electrical alternans?
Alternans due to cardiac motion is the most well-known mechanism of electrical alternans, encountered in large pericardial effusions and cardiac tamponade. The pendulous swinging motion of the heart in a fluid-suspended cavity in such situations effectively causes electrical alternans.
Is Pulsus alternans the same as electrical alternans?
Pulsus alternans is beat-to-beat variability of the arterial pressure waveform as identified on physical exam and echocardiogram. Electrical alternans is beat-to-beat variability of the QRS complex on electrocardiogram, often found in the setting of pericardial effusion.
What are alternans in ECG?
Introduction. Electrical alternans is defined as alternating QRS amplitude that is seen in any or all leads on an electrocardiogram (ECG) with no additional changes to the conduction pathways of the heart.
How do you treat electrical alternans?
Direct treatment toward correction of the underlying cause of electrical alternans, such as optimizing heart failure or anti-ischemic regimens in patients with cardiomyopathy or coronary disease. In the setting of long QT syndrome (LQTS), remove the offending drugs and correct concomitant dyselectrolytemias.
What is electrical alternans in ECG?
Electrical alternans is defined as alternating QRS amplitude that is seen in any or all leads on an electrocardiogram (ECG) with no additional changes to the conduction pathways of the heart. This rhythm is typically associated with pericardial effusion via the “swinging heart” from the fluid surrounding the heart.
Why are there Pulsus alternans in heart failure?
Pulsus alternans (during pulse palpation, this is the alternation of one strong and one weak beat without a change in the cycle length) occurs most commonly in heart failure due to increased resistance to LV ejection, as occurs in hypertension, aortic stenosis, coronary atherosclerosis, and dilated cardiomyopathy.
What does QRS amplitude mean?
The QRS represents the simultaneous activation of the right and left ventricles, although most of the QRS waveform is derived from the larger left ventricular musculature. QRS duration ≤ 0.10 sec. QRS amplitude is quite variable from lead to lead and from person to person.
What is Pulsus alternans indicative of?
Pulsus alternans is a physical finding with arterial pulse waveform showing alternating strong and weak beats. It is almost always indicative of left ventricular systolic impairment, and carries a poor prognosis.
When do you see Pulsus alternans?
What does the QRS represent on an ECG?
The QRS wave is produced by the atrioventricular node (AV). The P wave in an ECG complex indicates atrial depolarization. The QRS is responsible for ventricular depolarization and the T wave is ventricular repolarization.
Which is an ECG manifestation of QRS alternans?
ECG manifestations from this form of alternans may include alternating appearance of the P wave, QRS complex or alternating difference in P-R or R-R interval duration. In particular — QRS alternans during narrow SVT rhythms has been associated with reentry tachycardias.
Which is phasic variation associated with AVNRT and AVRT?
QRS alternans – phasic variation in QRS amplitude associated with AVNRT and AVRT, distinguished from electrical alternans by a normal QRS amplitude. Different subtypes vary in terms of the dominant pathway, and the R-P interval, which is the time between anterograde ventricular activation (R wave) and retrograde atrial activation (P wave).
What are the ECG features of AVRT with antidromic conduction?
AVRT with Antidromic Conduction. In antidromic AVRT anterograde conduction occurs via the accessory pathway with retrograde conduction via the AV node. Much less common than orthodromic AVRT occurring in ~5% of patients with WPW. ECG features of AVRT with antidromic conduction are: Rate usually 200 – 300 bpm.
Who is at risk of developing atrioventricular reentrant tachycardia ( AVRT )?
Individuals with accessory pathways are at risk of developing atrioventricular reentrant tachycardia (AVRT). This is a rapid tachyarrhythmia in which a macroscopic re-entry circuit which involves the atria, atrioventricular node, accessory pathway and the ventricles.