A 79-year-old man takes high-dose beta blockers for coronary disease. He presents with dizziness. ECG shows a heart rate of 42 per minute with narrow QRS complexes and no preceding P waves; inverted P waves are seen after some QRS complexes. Which of the following is the most likely source of this rhythm?
- A)Sinoatrial node
- B)Ventricular myocardium
- C)Accessory pathway
- D)AV junctionGABARITO
- E)Atrial ectopic focus
Explicação
A slow narrow-complex rhythm without preceding P waves and with possible retrograde inverted P waves indicates a junctional escape rhythm. This occurs when sinus node firing is suppressed and the AV junction takes over as the pacemaker. Ver explicação completa e trilha adaptativa →