[Morphologic classification of hypertrophic cardiomyopathy with myocardial single photon emission tomography. Comparison with echocardiographic classification]

[Physiologic evaluation of coronary circulation. Role of invasive and non invasive techniques]

For many years, the evaluation of the extent and severity of coronary artery disease has been mainly anatomical, carried out by coronary angiography. However, this technique has methodological limitations and interobserver variability is considerable. Quantification of coronary reserve with pressure guidewires and intracoronary Doppler now provides more precise physiologic evaluation of coronary circulation. Myocardial perfusion single proton emission computed tomography and echocardiography, combined with stress and/or pharmacological challenge testing, though they are only semiquantitative techniques, also offer appropriate complements to coronary angiography in the functional evaluation of coronary patients. The aim of this paper is to discuss the clinical value of these techniques.

[Myocardial perfusion SPECT and isotopic ventriculography in obstructive and non-obstructive hypertrophic myocardiopathy]

OBJECTIVE

To evaluate the role of myocardial perfusion SPET and radionuclide ventriculography in patients with hypertrophic cardiomyopathy (HC).

METHODS

Exercise myocardial perfusion SPET with 99mTc-tetrofosmin and radionuclide ventriculography were performed in a consecutive series of 101 patients (54 15 years, 50 women, 55 with dynamic obstruction) diagnosed of HC by echo. Follow-up from the diagnosis was 9,9 6,7 years (1 to 28 years).

RESULTS

Thirty six percent of patients had perfusion defects (non reversible in 15 and reversible in 21). In non obstructive HC higher number of patients with non reversible defects (p = 0.01 was obseved and in patients with no reversible defects higher incidence of pathologic Q waves in ECG (p = 0.01), Higher ventricular volumes (p < 0.05), lower ejection fraction (p = 0,0001) and longer time to peak emptying velocity (p < 0.05). There were 4 cardiac deaths, 15 syncopes, 18 pacemakers and 6 myectomy. Ejection fraction was higher in patients with syncope (p = 0,034) and there was no isotopic variable predictive of mortality, pacemaker or myectomy.

CONCLUSIONS

Neither SPET nor radionuclide ventriculography have a prognostic role in patients with HC, but patients with syncope have higher values of ejection fraction. Patients with non reversible defects have higher rate of pathologic Q waves in ECG, higher ventricular volumes and lower ejection fraction. This is indicative of evolution to dilated form of HC.

[Myocardial SPET in hypertrophic cardiomyopathy]

INTRODUCTION AND OBJECTIVES

The aim of this study was to evaluate the diagnostic accuracy of myocardial SPET in patients with hypertrophic cardiomyopathy (HC).

PATIENTS AND METHODS

One hundred and six consecutive patients (aged 53 +/- 12 years, 50 women, 66 with dynamic obstruction) with an echocardiographic diagnosis of HC were studied with exercise-rest myocardial SPET with 99mTc-tetrofosmin. Forty-six (43%) of these patients had chest pain and in 31 (29%) a coronary angiography was performed. Fifty-six per cent of the patients were treated with beta-blockers and 23% with verapamil.

RESULTS

Angina during the exercise test was observed in only 8% of the patients. Perfusion defects were observed in 35% of the patients. Only 8 (26%) out of the 31 patients with angiography had coronary artery disease (stenosis > 50%). When fixed and reversible defects were considered as positive, the sensitivity was 50%, the specificity was 65%, the positive predictive value was 33% and the negative predictive value was 79%.

CONCLUSIONS

Myocardial perfusion defects can be observed in more than one third of medically treated patients with HC. Only a quarter of catheterized patients, even with chest pain, have associated coronary artery disease. The accuracy of SPET for the diagnosis of coronary artery disease in hypertrophic cardiomyopathy is low. Thus, the value of this technique is limited in these patients.