Ventricular Rhythms Flashcard 1

B. Rationale: Ventricular fibrillation is an extremely irritable ventricular focus that makes the impulses fire chaotically, causing the ventricles to quiver and leading to a fatal arrhythmia because no sufficient cardiac output is produced. In ventricular fibrillation, there are no waves or complexes to identify. This is represented by a grossly chaotic fibrillatory pattern on ECG.

B. Rationale: A PVC followed by two sinus beats is known as trigeminy. A PVC between every other beat is known as bigeminy. A PVC that follows after three sinus beats is known as quadrigeminy. A PVC that follows five sinus beats is known as tetrageminy.

B. Rationale: An extremely irritable focus in the ventricles can override the heart’s pacemaker cells and cause a sustained run of PVCs. This is known as ventricular tachycardia. It has a rate of 150 to 250 bpm. The R-R interval has a slightly irregular appearance, but the intervals are generally uniform. Ventricular tachycardia presents with bizarre-looking QRS complexes that are > 0.12 seconds and a T wave that deflects opposite the R wave.

B. Rationale: The appearance of three or more consecutive PVCs is considered ventricular tachycardia.

Answer choice A – A sawtooth appearance within the isoelectric line represents atrial flutter.
Answer choice C – A variation in the amplitude of the QRS complex is not representative of ventricular tachycardia.
Answer choice D – A narrow QRS interval is usually characteristic of supraventricular tachycardia.
“

A. Rationale: This is an ECG of a patient in renal failure that progressed into torsade’s de pointes after being diagnosed with severe hyperkalemia. Torsade’s de pointes is a polymorphic ventricular tachycardia in which the wide QRS complexes have varying amplitudes that “twist” along the isoelectric line.

C. Rationale: Accelerated idioventricular rhythm generates impulses that assume control because they overcome the impulses from the sinus node. It occurs at a rate of 60–100 bpm. Atrioventricular dissociation may be present in which the atrial rate is slower than the ventricular rate. The P-P intervals are longer than the R-R intervals.

C. Rationale: The term “bigeminy” refers to a premature ventricular beat that occurs right after a normal beat.

Answer choice A – “Quadrigeminy” refers to a normal beat followed by 3 consecutive ventricular premature beats.
Answer choice B – The term “trigeminy” refers to a premature ventricular beat that occurs after two normal beats.
Answer choice D – A run of 7 or more premature ventricular beats is a risk factor for the development of ventricular tachycardia.

D. Rationale: A idioventricular rhythm is a ventricular escape rhythm that occurs due to the failure of higher pacemaker sites. There are no P waves because its origin is in the ventricles. It has a slower inherent rate of 20–40 bpm. Likewise, it has a QRS complex of 0.12 seconds and longer.

A. Rationale: A PVC that occurs early on top of the T wave is called an R-on-T phenomenon. This can induce ventricular tachycardia or ventricular fibrillation and is common in patients with an ischemic myocardium.

Answer choice B – Torsades de pointes is a polymorphic ventricular tachycardia usually induced by hypomagnesemia.
Answer choice C – AVNRT is a type of supraventricular tachycardia caused by a reentrant circuit within or close to the AV node.
Answer choice D – A delta wave is the characteristic finding of Wolff-Parkinson-White syndrome.

A. Rationale: Polymorphic PVCs may have impulses that are unifocal but coming from varying ventricular activation, which will show equal coupling intervals. Polymorphic PVCs may also be multifocal where there are varying coupling intervals.

Answer choice B – A bundle branch block is represented by a wide QRS complex > 0.12 seconds.
Answer choice C – An escape rhythm is a slow rhythm that is initiated by and causes contraction of the ventricles.
Answer choice D – Hypertrophic cardiomyopathy is represented by a strain pattern with an increased amplitude of the QRS complex.
“