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June 1985, Volume 35, Issue 6

Editorial

Angina Pectoris - Investigations and therapy

Fatema Jawad  ( Sugrabai Miliwalla Hospital, Karachi. )

A sense of Strangling anxiety - a painful and most disagreable sensation in the chest, is the description given by Heberden for angina pectoris1, which is a symptom of an underlying disease that has to be determined. The initial history, physical examination, electrocardiogram and simple laboratory tests will provide a clue to the cause which may be atherosclerotic coronary artery disease, non-atherosclerotic coronary artery disease, valvular heart disease, hypertrophic cardiomyopathy or hypertension.
The therapy for chronic stable angina can be initiated without delay. This includes control of hypertension, discontinuation of cigarette smoking and the use of either nitrates, beta adrenergic blockers or a calcium channel blocking agent. If mild or moderate symptoms still persist in the elderly patients who have a contraindication to by-pass surgery then no further tests are performed. Medical therapy is adjusted according to the need and continued. In other cases an exercise stress is undertaken to identify the high risk and low risk patients2. Patients having a heart rate of less than 160 per minute with no changes in the electrocardiogram have a good prognosis3. Whereas cases having an onset of ischaemic changes in the electrocardiogram within three minutes of exercise, persistence of S-I depression after exercise, widespread ischaemic changes in the electrocardiogram, S-T segment depression of 2mm or more and hypotension have a poor prognosis4. These abnormalities indicate a left main or three vessel coronary artery disease5 -Radionuclide imaging helps to improve the results of the exercise, tolerance test in the presence of abnormalities in the resting electrocardiogram as left ventricular hypertrophy, WPW syndrome, left bundle branch block and digoxin therapy.6,7,8,9
Patients with a good prognosis or those with ischaemic changes in the electrocardiogram during the exercise test, but having no criteria of a left main or three vessel disease, should continue with the medical therapy. Patients having a poor prognosis should be subjected to cardiac catheterization and angiography. If left main coronary disease is present then coronary by-pass surgery is not favourable. In patients with three vessel disease with left ventricular dysfunction, surgery is again preferable. In one or two vessel disease medical therapy is continued. Coronary angioplasty may be considered in this group of patients to improve the quality of life. Chronic angina with disabling symptoms inspite of intensive medical therapy, is a positive indication to coronary angioplasty or by-pass surgery.
Unstable angina cases require intensive medical therapy in hospital along with treatment of any of the precipitating factors if present. Most of them have a satisfactory response to medication. Those having refractory symptoms should be subjected to cardiac catheterization and those found to have marked coronary artery disease should undergo early coronary by-pass surgery. Patients with variant angina or prinzmetal angina should be investigated with a Holter monitor. If a positive finding is not obtained then cardiac catheterization is performed. If coronary stenosis is not demonstrated then vasospasm is provoked by Ergonovine infusion10. This should be performed with great caution as prolonged coronary spasm can lead to myocardial infarction. The spasm can be reversed by intracoronary injection of nitroglycerin. To arrive at a definite conclusion, nitrates and calcium blocking agents should be discontinued 12 to 24 hours before catheterization.
In variant angina, nitrates and calcium blocking agents usually control the symptoms very effectively11. But in patients having a fixed obstructive component, beta adrenergic bloèkers may have to be added. In case disabling symptoms persist, the patient should be re-assessed for coronary artery by-pass surgery or coronary angioplasty.
The evaluation of a patient with angina pectoris is necessary to make a decision regarding the mode of treatment medical or surgical.

References

1. Heberden, W. Some account of a disorder of the breast Med. Trans. Roy,Coll. Physicians, 1772; 2 : 59.
2. Epstein, S.F. Value and limitations of the electrocardiographic response to excercise in the assessment of patients with coronary artery disease. Am. J. Cardiol., 1978; 42: 667.
3. McNeer, J.F., Margolis, J.R., Lee, K.L. Kisslo, J.A., Peter, R.H., Kong, Y., Behar, V.S., Wallece, A.G., McCants, C.B. and Rosati, R.A. The role of the exercise test in the evaluation of patients for ischemic heart disease. Circulation, 1978; 57: 64.
4. Goldschlager, N., Selzer, A. and Cohn, K. Treadmill stress tests as indicators of presence and severity of coronary artery disease. Ann. Intern. Med., 1976; 85 : 277.
5. Weiner, D.A., McCabe, C.H. and Ryan, T.J. Identification of patients with left main and three vessel coronary disease with clinical and exçrcise test variables. Am. J. Cardiol., 1980; 46: 21.
6. Gibson, R.S. and Beller, GA. Should exercise electrocardiographic testing be replaced by rad&o isotope methods? in controversies in coronary artery disease. Edited by Rahimtoola.S.H. Phila­ delphia, Davis, 1983, V.13,pp 1 31.
7. Bailey, l.K, Griffith, L.S.C., Rouleau, J., Strauss, H.W. and Pitt, B. Thalluim 201 myocardial perfusion imaging at rest and during exercise; comparative sensitivity to electrocardiography in coronary artery disease. Circulation, 1977; 55: 79.
8. Ritchie, J.L., Trobaugh, G.B., Hamilton, G.W., Gould, KL., Narahara, KA., Murray, J.A. and Williams, D.L. Myocardial imaging with thailuim- 201 at rest and during exercise; comparison with coronary arteriography and resting and stress electrocardiography. Circulation, 1977; 56
9. Borer, J.S., Bacharach, S.L., Green, J.V., Kent, K.M., Epstein, S.E. and Johnston, G.S. Real time radionuclide cineangiography in the noninvasive evaluation of global and regional left ventricular function at rest and during exercise in patients with coronary artery disease. N. EngL J. Med., 1977;296: 839.
10. Waters, D.D., Szlachcic, J., Bonan, R., Miller, D.D., Dauwe, F. and Theroux, P. Comparative sensitivity of exercise, cold pressor and ergonovine testing in provoking attacks of variant angina in patients with active disease. Circulation, 1983; 67 : 310.
11. Ginsburg, R., Labm, l.H., Schroeder, J.S., Hu, M., and Harrison, D.C. Randomized double blind comparison of nifedipine and isosorbidc dinitrate therapy in variant angina pectoris due to coronary artery spasm. Am. Heart J., 1982 103 : 44.

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