Pharma-Arrhythmias Q2

1- after-polarisation; abnormally high Ca++>trains of APs. often causes ectopic beats.

2- re-entry: impulse re-excites previously active tissue>AP circulation. often associated with damaged heart tissue. 3- ectopic pacemaker activity; excessive automaticity/over activity of nodes or outside nodes.

AP encounters a region of the myocardium in refractory state>AP travels around the refractory cells via an alternative pathway and activate them via this "backpropagation"> refractory cells recover and depolarise out of sync>trigger additional contractions>arrhythmias.

wolfe-parkinson-white syndrome.

<p>1- it may cause atrial tachycardia transmitted to ventricles. 2- may cause (retrograde) re-entry tachycardia (from ventricular to atrial) treatment: surgical ablation.</p> Signup and view all the answers

<p>increases phase 4 depolarisation (pacemaker depolarisation), decrease in AP threshold.</p> Signup and view all the answers

<p>1- class I (a,b,c): VG Na+ blockers 2- class II: beta blockers 3- class III: VG K+ blockers 4- class IV: VG Ca2+ blockers 5- others: digoxin, adenosine</p> Signup and view all the answers

<p>black phase 0 (na+ influx)&gt;slow down AP generation&gt;slow down conduction through conductive tissue,</p> Signup and view all the answers

<p>oedema (ankle,feet), dizziness.</p> Signup and view all the answers

<p>at lower hear rate, fewer open/inactive Na+ channels&gt;less drug binding&gt;less effect.</p> Signup and view all the answers

<p>DQP. Disopyramide, Quinidine, and procainamide.</p> Signup and view all the answers