A 68-year-old man with a history of myocardial infarction presents with palpitations and dyspnea. Vital signs show BP 128/82 mmHg, HR 142 bpm, RR 18, temperature 37.2°C, and SpO2 98% on room air. ECG demonstrates wide-complex tachycardia. He denies chest pain. The patient takes metoprolol and atorvastatin. A researcher studying this arrhythmia's electrophysiology notes that a novel antiarrhythmic drug slows the rapid upstroke of phase 0 in ventricular myocytes. Which ion current is primarily affected?
- A)Slow calcium influx through L-type channels
- B)Potassium efflux through delayed rectifier channels
- C)Funny current in pacemaker cells
- D)Chloride influx
- E)Fast sodium influxGABARITO
Explicação
Phase 0 of the ventricular action potential is mediated by rapid influx of sodium through fast voltage-gated sodium channels. Class I antiarrhythmic drugs slow this upstroke and reduce conduction velocity in ventricular myocardium. Ver explicação completa e trilha adaptativa →