Ventricular tachycardia and ST
segment elevation during Exercise

Nguyen Huu Tram Em MD

Exercise Test Laboratory, MEDIC

Exercise-induced ventricular tachycardia is a phenomenon related to sudden deaths, especially in patients with severe heart disease (ischaemia, acquired valvular heart and congenital heart disease) accompanied with left ventricular dysfunction.In this article,we present a rare case ,which experienced exercise-induced ventricular tachycardia and ST segment elevation during exercise testing in the patient without previous myocardial infarction.

Case report:

A 46 year old woman admitted to the clinic because of vertigo and dizziness when upstairs or exercise, sometimes she felt mild chest pain.Several times ,she visited in some clinics and hospitals and vestibular disorders usually were diagnosed but symptoms were not relieved by any treatment for several months. Then, the patient visited a cardiologist but abnormalities were absent during physical examination. Chest film and echocardiogram were normal. Exercise testing was indicated for this case and flattened T waves were recognized in lateral anterior and inferior leads in resting ECG. Exercise testing was terminated at 90 watts workload with exercise duration of 6 minutes because of achieved 85% of predicted heart rate. Shortly,the patient developed to vertigo and angina and in this time ,sustained ventricular tachycardia (#200bpm) had appeared on electrocardiographic monitoring.Intravenous access and lidocain (60mg IV) were established.Four minutes later, sinus rhythm restored and ST segment elevation displayed in leads DII & aVF on monitoring.She was taken with a sublingual 5 mg Risordan tablet.Seven minutes later, ECG become near normal as resting ECG.Then, CK-MB was normal.

The patient was clinically stable for few day without specific ECG changes.A diagnosis of inferior ischemia and exercise-ventricular tachycardia was made.Unfortunately,coronary angiography could'n performed because this technique was not available in Vietnam in the past few years.

Discussion:

In this case, some symptoms as vertigo, dizziness sometimes make physicians misdiagnosis for a long times.Before making a diagnosis of functional state, physician should rule out true diseases by resonable diagnostic techniques.

Unlike ST segment depression, ST segment elevation in exercise testing in patients without previous myocardial infarction as the same as this case is a rare phenomenon(1,2,3), approximately 1/1000 tests. In our study of 16.000 tests,perfomed in exercise test laboratory of MEDIC, rate of this phenomenon is 0,81/1000 tests, it is consistent to data from some researchers(1,3) and it is dependent on studied population. Patients with exercise-induced ST segment elevation usually associated with significant arrhythmias (4,5), thus, should experience coronary angiography to make clinical dicision depending on coronary anatomy(6). Interventional therapy(angioplasty with or without stent or bypass surgery) is indicated for patients with critical coronary stenosis.Therapeutic therapy (calcium channel antagonists, nitrates) usually indicated for patients with coronary spasm but no stenosis(6).In cases with coronary spasm contractable to drugs, stenting may be indicated (7,8).Coronary spasm is diagnosed by provocative test with acetylcholine or ergonovine if normal coronary angiogram (9). In a recent study by Song J K at al.(10), a non-invasive test as ergonovine stress echocardiography which was suggested in using diagnosis of coronary spasm.Despite this study of more 1000 patients have shown that the test is safe , some patients may develop severe coronary spasm ,who need interventional treatment.Thus this technique not assure safety for these patients and further studies are needed.

Reference:

  1. V.F. Froelicher, Susan Quaglietti. Handbook of Exercise Testing.1st Ed. A Little & Brown 1996

  2. Labbe L, Douard H, Espil G, Chevalier L, Parrens E, Dissoubray E, Broustet JP. Significance of exercise induced ST elevation in patient without a history of previous myocardial infarct. Arch Mal Coeur Vaiss 1999 Oct; 92(10):1287-94

  3. Candell Riera J, Castell J, Rius A, Buxeda M, Moragas G. ST segment elevation during exercise test and perfusion Scintigraphy in patients without Infarction. Rev Esp Cardiol 1995 sep ;48(9):600-5.

  4. Robert J. Myerburg, Kenneth M. Kessler, Stephen M Mallon. Life-threatening ventricular arrhythmias in patients with silent myocardial ischemia due to coronary artery spasm. N Engl J Med 1992; 326:1451-5

  5. Specchia G, La Rovere MT, Falcone C. Cardiac arrhythmias during exercise -induced myocardial ischemia in patients with coronary artery disease.Eur Heart J 1986 May;7 Suppl A:45-52.

  6. Gallik DM, Mahmarian JJ, Verani MS. Therapeutic significance of exercise-induced ST-segment elevation in patients without previous myocardial infarction.Am J Cardiol 1993 Jul 1;72(1):1-7

  7. Achille Gaspardone, Fabrizio Tomai, Francesco Versaci… Coronary artery stent placement in patients with variant angina refractory to medical treatment. Am J Cardiol 1999 1 july ; 84:96-98

  8. Kultursay H, Can L, Payzin S, Turkoglu C, Altintig A, Akin M, Akili A. A rare indication for stenting: persistent coronary artery spasm. Heart Vessels, 1996;11(3):165-8.

  9. Patrick J Scanlon, David P Faxon, Anne-Marie Audet. ACC/AHA Guidelines for Coronary Angiography: Executive Summary and Recommendations. Circulation 1999;99: 2345-57

  10. Song J.K., Park S.W. and Kang D.H. et al. Safety and clinical impact of ergonovine stress echocardiography for the diagnosis of coronary vasospasm. J Am Coll Cardiol 2000, 35:1850-1856.

 


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