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Patterns of left ventricular dilation during the six months after myocardial infarction
R W Jeremy1, K C Allman, G Bautovitch
1Hallstrom Institute of Cardiology, Department of Nuclear Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
Insights
Left ventricular dilation after myocardial infarction is common, with progressive dilation linked to larger infarcts and reduced ejection fraction. This progression is associated with increased mortality, highlighting its clinical significance.
Area of Science:
- Cardiology
- Cardiovascular Imaging
- Heart Failure Research
Background:
- Myocardial infarction (MI) can lead to adverse cardiac remodeling.
- Left ventricular (LV) volume changes are critical indicators of post-MI prognosis.
Purpose of the Study:
- To investigate the incidence and progression of left ventricular dilation after a first myocardial infarction.
- To correlate LV dilation patterns with infarct characteristics and patient outcomes.
Main Methods:
- Serial radionuclide angiograms were performed on 50 patients post-MI at multiple time points (48h, 10 days, 1 month, 6 months).
- Left ventricular volume was measured using a non-geometric method.
- Left ventricular dilation was defined as ≥20% increase in end-diastolic volume.
- Progressive dilation was defined as ≥20% serial volume increases on two or more occasions.
Main Results:
- Left ventricular dilation occurred in 21 of 50 patients.
- Progressive dilation was observed in 8 patients, all with large anterior infarcts.
- Patients with progressive dilation showed significant increases in LV volume (79% at 6 months) and decreased ejection fraction (24% at 1 month).
- Mortality was higher in patients with progressive dilation (4 of 6 deaths).
Conclusions:
- Left ventricular dilation is a significant complication following myocardial infarction.
- Progressive dilation, particularly with large anterior infarcts, is associated with worsening cardiac function and increased mortality.
- Early identification and monitoring of LV remodeling are crucial for managing post-MI patients.
Abstract:
Changes in left ventricular volume after a first myocardial infarction were studied in 50 patients. Serial radionuclide angiograms were obtained 48 h, 10 days and 1 and 6 months after infarction and left ventricular volume measured by a nongeometric method. Left ventricular dilation (greater than or equal to 20% increase in end-diastolic volume) occurred within 10 days of infarction in 11 patients, who had a mean volume increase of 34 +/- 15% (p = 0.002 versus 48 h) at 10 days and 61 +/- 43% (p = 0.01 versus 10 days) at 6 months. Ten other patients manifested left ventricular dilation between 10 days and 6 months with a lesser volume increase of 42 +/- 18% by 6 months. Among the 21 patients with ventricular dilation, progressive dilation (serial volume increases greater than or equal to 20% on two or more occasions) occurred in 8 patients, who all had a large anterior infarct. Mean volume increases at 10 days and 1 and 6 months were 27 +/- 20%, 49 +/- 40% (p = 0.03 versus 10 days) and 79 +/- 37% (p = 0.006 versus 1 month), respectively, in this group. In patients with progressive dilation, left ventricular ejection fraction decreased from 35 +/- 6% at 48 h to 24 +/- 10% at 1 month (p less than 0.001) and 27 +/- 10% (p = 0.006) at 6 months. Between 1 month and 2 years after infarction six patients died, of whom four had progressive dilation.(ABSTRACT TRUNCATED AT 250 WORDS)