What are alternans in ECG?

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.

What does low voltage QRS mean?

Low QRS voltage (LQRSV), defined as QRS complex amplitudes of <0.5 mV in all frontal leads and/or <1.0 mV in all precordial leads, is present in about 1% to 2% of normal lean individuals.

What causes Pulsus Paradoxus?

Pulsus paradoxus results from alterations in the mechanical forces imposed on the chambers of the heart and pulmonary vasculature and is often due to pericardial disease, particularly cardiac tamponade and to a lesser degree constrictive pericarditis.

Why are narrow QRS supraventricular tachycardia?

A narrow QRS complex (<120 milliseconds) reflects rapid activation of the ventricles via the normal His-Purkinje system, which in turn suggests that the arrhythmia originates above or within the His bundle (ie, a supraventricular tachycardia).

Do you Anticoagulate for SVT?

Synchronized cardioversion is recommended (moderate-quality evidence) for the termination of any hemodynamically unstable SVT. In the absence of hemodynamic compromise, SVT should be treated (moderate-quality evidence) with synchronized cardioversion when pharmacologic therapy is ineffective or contraindicated.

Is low voltage QRS serious?

Low voltage on the electrocardiogram is a marker of disease severity and a risk factor for adverse outcomes in patients with heart failure due to systolic dysfunction.

Is low voltage QRS bad?

Background. Low QRS voltage has been shown to be associated with increased mortality in the general population and in a small pilot study the combined QRS voltage of ECG leads I and II was found to be associated with in-hospital mortality.

What happens during pulsus paradoxus?

Pulsus paradoxus, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop is more than 10 mmHg, it is referred to as pulsus paradoxus.

What is supraventricular tachycardia (SVT)?

↪ ECG Library Homepage. The term supraventricular tachycardia (SVT), whilst often used synonymously with AV nodal re-entry tachycardia (AVNRT), can be used to refer to any tachydysrhythmia arising from above the level of the Bundle of His.

What is the mechanism of pseudoelectrical alternans During SVT?

The mechanism of pseudoelectrical alternans during narrow complex SVT is not very clear and has been attributed to nonspecific intraventricular conduction abnormalities or rocking heart [2].

Is QRS width related to heart palpitations?

Classification based on QRS width is unhelpful as this is also influenced by the presence of pre-existing bundle branch block, rate-related aberrant conduction or presence of accessory pathways. AVRT AVNRT This is the commonest cause of palpitations in patients with structurally normal hearts.

What are the general features of AVNRT?

General Features of AVNRT. Regular tachycardia ~140-280 bpm. QRS complexes usually narrow (< 120 ms) unless pre-existing bundle branch block, accessory pathway, or rate related aberrant conduction. ST-segment depression may be seen with or without underlying coronary artery disease.