Key Points Origin: PJCs originate from ectopic foci near the AV junction, leading to premature impulses. ECG Characteristics: P Waves: May be absent or retrograde (inverted), appearing before, during, or…
Key Points Spontaneous Depolarization: Different pacemaker cells in the heart can spontaneously depolarize at varying rates; the SA node is usually the fastest. Ectopic Impulses: Early depolarizations from ectopic foci…