P Wave Abnormalities Flashcard

A. Rationale: The P wave represents atrial depolarization. The sinoatrial node is the origin of normal impulse conduction in the heart, which is seated in the right atrium. When an impulse originates from the SA node, this is known as sinus rhythm. Hence, all ECG tracings with sinus rhythm should have a P wave. On the contrary, an ECG tracing without a P wave is a non-sinus rhythm.

Answer choice B – Any rhythm labeled as a “sinus” rhythm will have a P wave, indicating that the impulse originated from the SA node.
Answer choices C & D – There is not enough information to conclude that this rhythm is either an AV block or ventricular tachycardia.

A. Rationale: Inverted P waves are a concrete finding in premature atrial beats. This represents an aberrant focus in the atria that can conduct a premature atrial beat.

Answer choice B – Peaked or hyper acute T waves are an indication of early stage STEMI, particularly if the patient is symptomatic with a high pretest probability for coronary artery disease.
Answer choice C – Inverted T waves may be a normal variant when seen in some precordial leads, such as lead V1 and V2, but the finding can also be a sign of other diseases such as coronary ischemia and pulmonary embolism.
Answer choice D – Prolonged PR interval may signify conduction defects such as first-degree AV block.