Acute Left Ventricular Dynamic Effects of Primary Percutaneous Coronary Intervention

OBJECTIVES: We studied the left ventricular (LV) dynamic effects of primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) by directly obtaining pressure-volume (PV) loops during the procedure. BACKGROUND: An acute myocardial infarction causes a decrease in LV compliance. The instantaneous effects of primary PCI on LV compliance are unknown. METHODS: We studied 15 consecutive patients (10 males, ages 59 +/- 12 years), who presented with their first acute anterior STEMI within 6 h after onset of symptoms, and in whom coronary angiography revealed an occluded left anterior descending coronary artery. Before performing primary PCI, we inserted a pressure-conductance catheter in the LV to continuously obtain PV loops. RESULTS: Immediately after successful reperfusion, significant improvements were observed in LV diastolic function, as indicated by an increased end-diastolic compliance with a 6.0 +/- 2.8 mm Hg (p < 0.0001) downward shift of the compliance curve. There was a decrease in end-diastolic pressure of 24 +/- 18% (p = 0.0002), in stiffness of 27 +/- 18% (p = 0.0003), and in wall stress of 20 +/- 24% (p = 0.004). Systolic function mainly showed an immediate improvement in apical contractility from 40 +/- 17% to 54 +/- 15% (p = 0.01). CONCLUSIONS: Primary PCI in anterior STEMI patients causes an immediate improvement in diastolic function, assessed by online PV loop measurements.