Cardiovascular Drugs

Question 1

Phases of Action Potential (AP) and comparing with ECG depolarisation

Answer 1

From resting membrane potential comes Phase 0 which is Na ion channel entry , 1 is Na closure both 0 and 1 are QRS in ECG which is ventricular depolarisation but also slight phase 2 which is K channel efflux and Ca channel entry a.k.a plateau phase which is mostly the ST segment in ECG so serum Ca abnormality affects it…….and lastly phase 3 which is Ca channel closure and K channel efflux ……only so T wave is phase 3 which reflects in hypo or hyperkelemia……N.B : K channel blocker increase AP duration so it causes QT prolongation

Question 2

Antiarrythmic drugs classificatin

Answer 2

Class- 1 )Na channel blocker + a) with K channel blocking property, b) with K channel opening property, c) no effect on K channel………class- 2) B blocker , 3) K channel blocker , 4) CCB