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  2. Sinus node dysfunction - Wikipedia

    en.wikipedia.org/wiki/Sinus_node_dysfunction

    Often sinus node dysfunction produces no symptoms, especially early in the disease course. Signs and symptoms usually appear in more advanced disease and more than 50% of patients will present with syncope or transient near-fainting spells as well as bradycardias that are accompanied by rapid heart rhythms, referred to as tachycardia-bradycardia syndrome [4] [5] Other presenting signs or ...

  3. Left axis deviation - Wikipedia

    en.wikipedia.org/wiki/Left_axis_deviation

    The hexaxial reference system is a diagram that is used to determine the heart's electrical axis in the frontal plane.. In electrocardiography, left axis deviation (LAD) is a condition wherein the mean electrical axis of ventricular contraction of the heart lies in a frontal plane direction between −30° and −90°.

  4. Left atrial enlargement - Wikipedia

    en.wikipedia.org/wiki/Left_atrial_enlargement

    Left atrial enlargement can be mild, moderate or severe depending on the extent of the underlying condition. Although other factors may contribute, left atrium size has been found to be a predictor of mortality due to both cardiovascular issues as well as all-cause mortality.

  5. P wave (electrocardiography) - Wikipedia

    en.wikipedia.org/wiki/P_wave_(electrocardiography)

    P-wave changes in left and right atrial hypertrophy. Bifid P waves (known as P mitrale) indicate left-atrial abnormality - e.g. dilatation [6] or hypertrophy. [1] If at least three different shaped P waves can be seen in a given ECG lead tracing, this implies that even if one of them arises from the SA node, at least two others are arising ...

  6. Junctional rhythm - Wikipedia

    en.wikipedia.org/wiki/Junctional_rhythm

    The most obvious abnormal finding will be abnormal P waves. One of three options can occur: [12] 1. There are no P waves. This is because of either failure of retrograde flow to the atria or the P wave is hidden in the QRS. If the P wave is hidden that implies the atria depolarize at the same time as the ventricles. 2.

  7. Third-degree atrioventricular block - Wikipedia

    en.wikipedia.org/wiki/Third-degree_atrio...

    Atrial tachycardia with complete A-V block and resulting junctional escape Many conditions can cause third-degree heart block, but the most common cause is coronary ischemia . Progressive degeneration of the electrical conduction system of the heart can lead to third-degree heart block.

  8. Premature atrial contraction - Wikipedia

    en.wikipedia.org/wiki/Premature_atrial_contraction

    Premature atrial contractions are often benign, requiring no treatment. Occasionally, the patient having the PAC will find these symptoms bothersome, in which case the doctor may treat the PACs. Sometimes the PACs can indicate heart disease or an increased risk for other cardiac arrhythmias .

  9. Electrical alternans - Wikipedia

    en.wikipedia.org/wiki/Electrical_alternans

    Electrical alternans is an electrocardiographic phenomenon of alternation of QRS complex amplitude or axis between beats and a possible wandering base-line. It can be 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 ...