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The criteria to diagnose a right bundle branch block on the electrocardiogram: The heart rhythm must originate above the ventricles (i.e., sinoatrial node, atria or atrioventricular node) to activate the conduction system at the correct point. The QRS duration must be more than 100 ms (incomplete block) or more than 120 ms (complete block). [9]
A right bundle branch block typically causes prolongation of the last part of the QRS complex and may shift the heart's electrical axis slightly to the right. The ECG will show a terminal R wave in lead V1 and a slurred S wave in lead I. Left bundle branch block widens the entire QRS, and in most cases shifts the heart's electrical axis to the ...
An intraventricular block is a heart conduction disorder — heart block of the ventricles of the heart. [1] An example is a right bundle branch block, right fascicular block, bifascicular block, trifascicular block. [2] [3]
The ostium primum atrial septal defect is a defect in the atrial septum at the level of the tricuspid and mitral valves. This is sometimes known as an endocardial cushion defect because it often involves the endocardial cushion, which is the portion of the heart where the atrial septum meets the ventricular septum and the mitral valve meets the tricuspid valve.
The bundle branches were separately described by Retzer and Braeunig as early as 1904, but their physiological function remained unclear and their role in the electrical conduction system of the heart remained unknown until Sunao Tawara published his monograph on Das Reizleitungssystem des Säugetierherzens (English: The Conduction System of the Mammalian Heart) in 1906. [4]
The bundle of His (BH) [1]: 58 or His bundle (HB) [1]: 232 (/ h ɪ s / "hiss" [2]) is a collection of heart muscle cells specialized for electrical conduction.As part of the electrical conduction system of the heart, it transmits the electrical impulses from the atrioventricular node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the ...
Tachycardia-dependent bundle branch block (TDBBB) can affect either ventricle in the heart, and occurs when the heart's rate of contraction reaches an elevated level and becomes uncoupled from the heart's refractory period (the time it takes for a cardiac cell to "reset" for future contraction).
Prolonged duration could indicate hyperkalemia [5] or intraventricular conduction delay such as bundle branch block. QRS amplitude: S amplitude in V1 + R amplitude in V5 < 3.5 millivolt (mV) [4] R+S in a precordial lead < 4.5 mV [4] R in V5 or V6 < 2.6 mV; Increased amplitude indicates cardiac hypertrophy: Ventricular activation time (VAT) < 50 ...