Sinus Rhythm & Core Variations · Normal Sinus Rhythm (NSR): The physiological standard. Regular rhythm (60-100 bpm), with a normal P wave preceding each narrow QRS complex. · Sinus Tachycardia: >100 bpm. A normal physiological response to demand (e.g., exercise) or a sign of pathology (e.g., fever, anemia). · Sinus Bradycardia:

Differentiating Sinus Tachycardia vs. Atrial Tachycardia: A Quick Guide ⚡️❤️ 🔹 Sinus Tachycardia · Normal P waves (upright in I, II, aVF) · Gradual onset/offset · Rate usually 100–180 bpm · Always 1:1 AV conduction · 🧠 Physiologic response → Treat the underlying cause 🔹 Atrial Tachycardia · Abnormal P-wave morphology (± inverted/notched) · Abrupt onset/offset (may warm-up/cool-down) · Rate typically 130–250 bpm · ❗AV block possible (key clue!) · ⚡ Intrinsic arrhythmia → Treat the rhythm (vaga