Prolonged diastolic dysfunction following exercise induced ischaemia: a gated myocardial perfusion SPECT study

Area of Science:

• Cardiology
• Nuclear Medicine
• Cardiovascular Imaging

Background:

• Left ventricular (LV) systolic dysfunction post-exercise ischemia is established.
• The impact of exercise-induced ischemia on post-stress LV diastolic function in coronary artery disease (CAD) patients requires further investigation.

Purpose of the Study:

• To assess the effect of exercise-induced ischemia on post-stress LV diastolic function in patients with CAD.
• To determine the relationship between ischemia severity and diastolic impairment.

Main Methods:

• Seventy-four subjects with suspected or known CAD underwent gated myocardial single-photon emission computed tomography (SPECT) post-exercise.
• LV volumes, ejection fractions (LVEFs), peak filling rate (PFR), and time-to-PFR (TPFR) were calculated.
• Fourier transformation of gated SPECT volume curves analyzed diastolic function.

Main Results:

• Patients with exercise-induced ischemia (n=26) showed significantly impaired post-stress PFR and TPFR compared to rest.
• Normal subjects (n=26) and patients with infarction (n=22) had similar post-stress and resting diastolic function indices.
• The summed reversibility score, indicating ischemia severity, was the sole predictor of post-stress LVEF and PFR changes.

Conclusions:

• Exercise-induced LV diastolic impairment persists long after the ischemic episode resolves.
• The severity of exercise-provoked ischemia dictates the incidence and magnitude of persistent diastolic dysfunction.
• Diastolic dysfunction following ischemia is a significant finding in CAD patients.