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Long-term effect of inducible silent ischaemia on left ventricular systolic function
1Department of Cardiology, St Bartholomew's Hospital, London, UK.
Insights
Silent myocardial ischemia, detectable by exercise radionuclide ventriculography in coronary artery disease patients, does not worsen left ventricular function over 12 months if patients remain asymptomatic and event-free on medication.
Area of Science:
- Cardiology
- Nuclear Cardiology
Background:
- Silent myocardial ischemia is common in coronary artery disease (CAD).
- The impact of inducible silent ischemia on left ventricular (LV) function in asymptomatic, event-free patients on anti-ischemic medication is not well understood.
Purpose of the Study:
- To investigate whether inducible silent myocardial ischemia, despite anti-ischemic medication, detrimentally affects left ventricular function in asymptomatic CAD patients over 12 months.
Main Methods:
- Prospective study of 34 medically treated CAD patients (mean age 57).
- Left ventricular ejection fraction (LVEF) measured at rest and peak exercise using radionuclide ventriculography at baseline and 12 months.
- Patients continued anti-ischemic medication throughout the study.
Main Results:
- No significant deterioration in LVEF was observed at rest (50% vs 49%) or peak exercise (44% vs 45%) from baseline to 12 months.
- The change in LVEF from rest to exercise also showed no significant difference (-6% vs -4%).
- These findings were consistent in patients who remained asymptomatic and event-free.
Conclusions:
- Inducible silent myocardial ischemia in asymptomatic, event-free CAD patients on medical therapy does not appear to cause a decline in left ventricular systolic function over a 12-month period.
- LV function remains stable despite the presence of inducible ischemia under these conditions.
Abstract:
Silent myocardial ischaemia is readily detected by exercise radionuclide ventriculography in patients with coronary artery disease. In those who remain asymptomatic and event-free, it is not known whether silent ischaemia which is inducible despite anti-ischaemic medication exerts an insidious detrimental effect on left ventricular function. To study this, 34 medically treated patients (mean age 57; 26 men) underwent prospective measurement of left ventricular ejection fraction (LVEF) during rest and exercise radionuclide ventriculography without interruption of anti-ischaemic medication at baseline and 12 months later. There was no significant mean (standard deviation, 95% confidence interval) deterioration from baseline to 12 months in LVEF at rest (50% v 49%, SD 5; 95% CI = -3 to +1), peak exercise (44% v 45%, SD 8; 95% CI = -1 to +4) and the change in LVEF from rest to exercise (-6% v -4%, SD 7; 95% CI = -1 to +5). Thus, in coronary artery disease patients who remain asymptomatic and event-free on medical therapy, silent myocardial ischaemia which is readily inducible at baseline despite medication does not lead per se to deterioration of left ventricular systolic function at rest or exercise over 12 months.