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Reg rhythm supports VT |
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QRS thats >0.14 seconds usually indicates ventricular origin except in BBB and WPW |
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Common cause of distorted T is the P wave. Look for atrial activity in the T wave of the preceding QRS. Look at the beginning of the rhythm for a detected PAC starting the tachycardia this means SV rhythm. A pattern that's similar to previous atrial or junctional beats with aberrant conduction comfirms SVT. |
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Single most important criteria for the most percentage of VT To identify AVD run long rhythm strip during the tachycardia to identify independent beating of the atrial & ventricles. Look at the right-side chest leads, v2r, v3r, v4r which are useful for identifying atrial activity. |
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If the sinus beat breaks thru and regains control of the rhythm for a instance, PQRST is created with a narrow QRS & a normal PR interval in the midst of a wide-complex tachycardia. This is called a captured beat....strong evidence of a ventricular origin. |
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Shape of QRS could be caused by AMI, ischemia, cardiac surgery, fibrosis, hypertension, aneurysms, metabolic & electrolyte disorders or intrinsic conduction disturbances. If the initial 0.04 second of the QRS looks different from the normal beats....ventricular origin. SV rhythm is easily spotted with the same pattern of the preexisting BBB with the same pattern as the current one. |
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Involves looking at the deflection of the QRS in 6 frontal leads I, II, III, AVR, AVL, & AVF QRS deflections are normal in all except AVR. Quickest way look AVR....normal atrial & ventricular deploration moves away & produces negative complexes. However, because VT causes ventricular conduction first, the impulse moves upward to the AV node & atria, causing positive P waves & QRS complexes in AVR. Positive complexes represent an indeterminate axis 90 & 180 degrees. .... strong indication of VT. Dx of VT is a left axis deviation which is associated with tachycardias that have positive QRS in V1 or MCL.....exception is SVT with WPW. |
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Onset of reg wide-complex tachycardia in the midst of afib, suspect VT . Ventricular origin is likely in a patient with freq wide premature beats in the midst of afib, especially if these beats have a fixed or persistent relationship to the preceding normal beat. Ventricular origin is easier to confirm if the patient develps a rapid, reg rhythm that looks like these premature beats. |
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If the wide-complex tachycardia is extremely rapid the rhythm prob AFL or AFIB with conduction thru the accessory pathway. |
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Predisposition to both ectopy & aberration when a longer R-R interval precedes a shorter R-R. This occurs in sinus rhythms & afib. |
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