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Premature Ventricular Contractions

caution
Lead II
25 mm/s10 mm/mV
Heart rate
72bpm
RR
833ms
QT
358ms
Type

Ventricular Bigeminy

A repeating pattern where every other beat is a PVC. The ventricular ectopic focus fires with a fixed coupling interval after each sinus beat, producing a strictly alternating normal-PVC pattern.

Mechanism

A repeating pattern where every other beat is a PVC. The ventricular ectopic focus fires with a fixed coupling interval after each sinus beat, producing a strictly alternating normal-PVC pattern.

Findings· 3
  • Alternating pattern: one normal sinus beat (narrow QRS) followed by one PVC (wide, bizarre QRS with no preceding P wave and discordant T wave).
  • Fixed coupling interval.
  • Compensatory pause after each PVC.
Clinical Impact

Often associated with digitalis toxicity, hypokalemia, or structural heart disease. The 50% PVC burden significantly reduces cardiac output and can lead to PVC-induced cardiomyopathy.

Differential· 2
PAC with Aberrancy

Premature beat with wide QRS from rate-dependent BBB. Look for preceding abnormal P wave.

Ventricular Tachycardia

Three or more consecutive PVCs = VT by definition. Same wide QRS morphology.