the heart and that Flashcards
class I anti-arrhythmic drugs
block sodium channels, e.g. lidocaine, reduce maximum rate of depolarisation. used to treat ventricular dysrhythmias.
class II anti-arrhythmic drugs
beta-adrenoreceptor antagonists e.g. atenolol. used to treat tachyarrhythmias. decrease mortality post MI.
class III anti-arrhythmic drugs
block potassium channels e.g. amiodarone. slow repolarisation and prolong cardiac action potential, thereby increasing refractory period.
class IV anti-arrhythmic drugs
calcium channel antagonists e.g. verapamil. block L-type calcium channels, slow conduction in SAN and AVN. used to treat supraventricular tachycardias (SVTs)
left-sided failure
often associated with raised blood pressure(hypertension or ischaemic heart disease). blood backs up in the lungs leading to pulmonary oedema- makes breathing difficult.
right-sided failure
output fails due to raised pressure in the lungs or valvular disease. blood backs up in the tissues, leading to peripheral oedema, ascites, liver enlargement
problems with the delivery of blood
lead to ischaemia
atherosclerosis
a disease of larger arteries- common in coronary and carotid arteries
symptoms of hypertension
- coronary arteries- angina (chest pain), complete blockage or release of thrombus can cause a heart attack
- carotid artery- slurred speech, muscle weakness, most severe outcome is stroke.
- renal artery- hypertension (renal stenosis)
- arms-legs: muscular pain on exercise.
hypertension
the level above which therapeutic intervention reduces the risk of cardiovascular disease.
diastolic BP>90mmHg
systolic BP>140mmHg
treatment of hypertension
lifestyle, pharmacological- treat symptom rather than cause. reducing DBP by about 5-6mmHg reduce incidence of strike and coronary heart disease by 40 and 25% respectively
