Silent left ventricular dysfunction during routine activity after thrombolytic therapy for acute myocardial...

Area of Science:

• Cardiology
• Cardiovascular Imaging
• Clinical Medicine

Background:

• Post-myocardial infarction (MI) patients often have residual cardiac dysfunction.
• Thrombolytic therapy improves outcomes but can be followed by transient left ventricular dysfunction.
• Assessing left ventricular function at discharge is crucial for prognosis.

Purpose of the Study:

• To prospectively evaluate the occurrence and prognostic significance of transient left ventricular dysfunction (TLVD) in post-MI patients.
• To compare TLVD detected during normal activity with exercise test results.
• To identify predictors of cardiac events after MI.

Main Methods:

• 33 ambulatory post-MI patients treated with thrombolysis were monitored continuously using radionuclide left ventricular function detector.
• Monitoring occurred during normal activity for 187 ± 56 minutes at hospital discharge.
• Ejection fraction (EF) changes and cardiac events were assessed at baseline and 19.2 ± 5.4 months follow-up.

Main Results:

• 12 patients experienced 19 episodes of TLVD (EF decrease >0.05, lasting ≥1 min) without heart rate changes.
• Only 2 episodes were symptomatic; baseline EF did not differ between patients with and without TLVD.
• Cardiac events occurred in 8/12 patients with TLVD versus 3/21 without TLVD (p<0.01).

Conclusions:

• Silent transient left ventricular dysfunction episodes are common in post-MI patients treated with thrombolysis.
• TLVD at hospital discharge is associated with a significantly higher risk of future cardiac events.
• Continuous monitoring of left ventricular function during normal activity provides prognostic information superior to submaximal exercise testing.