Echocardiographic evaluation of left ventricular function after taking amlodipine for hypertension and chronic stable angina on 507 rural human subjects
|The ORION Medical Journal 2009 Sep;32(3):675-678
Calcium Channel Blockers (CCBs) may be divided into benzothiazepine (diltiazem); phenylalkylamine (verapamil); and dihydropyridines (first generation: Nifedipine, nicardipine, felodipine, nisoldipine; second generation: isradipine, nimodipine; third generation: amlodipine, lacidipine etc).
Amlodipine is a third generation CCB with long half-life. It has interaction with specific high affinity binding sites in the calcium channel complex. It maintains therapeutic efficacy throughout 24 hours. It has less negative inotrophic and chronotrophic action, having lack of clinically, relevant increase in cardiac or peripheral sympathetic activity. It has higher lipophilicity; reflex tachycardia is minimal, relatively safe in heart failure.3
The L-type calcium channel is the dominant type in cardiac & smooth muscle. The calcium channel blockers act from the inner side of the membrane and bind more effectively to channels in depolarizing membranes.
In the cardiac myocyte, Ca++ binds to troponin and reduces inhibitory effects of troponin on contraction, favouring muscle contraction. CCBs reduce transmembrane movement of Ca.++ reduce the amount reaching intracellular sites and therefore reduce vascular smooth muscle tone.
Amlodipine has got minimal or no effect on AV conduction.4
CCBs have direct negative inotrophic effects and showed some benefits on haemodynamic parameters alone or in combination with ACE inhibitors. Amlodipine has got potentially beneficial effects on hypertension and coronary artery disease specially stable angina. But amlodipine showed minimal beneficial effects in patients with heart failure which was observed on large, randomized, placebo-controlled trials.5
Aims and objectives
Materials and methods
It is a prospective, community based, single blind, mono-centric, clinical study performed in a Community Health Care Centre, Chatkhil, Noakhali from 23.06.2006 to 21.09.2008.
A larger geographical area of Noakhali district i.e. Chatkhil, Sonaimuri, Begumgonj and part of Lakhipur and Comilla districts were fairly covered in this study.
All patients attending the OPD were screened. Patients of hypertension & IHD (stable angina) were selected for study. Age limit was 20-80 years; no gender variation; Associated heart failure was not a contraindication for inclusion. Consent was taken from all patients or relatives prior entry to study.
After clinical case selection, patients were investigated by X-ray, ECG, Echo, & for blood glucose and lipid profile. Then amlodipine therapy (5 mg daily) was given with other
Volume 32,Issue 3,September 2009