Ventricular dilation after anterior ST-elevation myocardial infarction in the thrombolytic era

Association of QRS duration with left ventricular volume and ejection fraction after anterior myocardial infarction assessed by gated single photon emission computed tomography

BACKGROUND

Even intermediate QRS prolongation without bundle branch block is associated with worse clinical outcome after myocardial infarction (MI). We assessed the association of QRS duration with left ventricular (LV) volume and ejection fraction after anterior MI by using quantitative gated single photon emission computed tomography (SPECT).

METHODS

Eighty-two patients with prior anterior MI were enrolled. Intermediate QRS prolongation was defined as QRS duration ≥100 ms without bundle branch block. Quantitative analysis of thallium SPECT was performed on the redistribution image. LV end-diastolic volume (LVEDV), end-systolic volume (LVESV) and ejection fraction (LVEF) were obtained.

RESULTS

There were 25 patients with intermediate QRS prolongation and 57 patients with normal QRS duation. Compared to patients with normal QRS duration, patients with intermediate QRS prolongation had larger LVEDV (137.4 ± 75.1 ml vs 87.9 ± 43.6 ml, p = .004), larger LVESV (89.9 ± 69.6 ml vs 49.2 ± 35.5 ml, p = .009) and lower LVEF (39.3 ± 14.6% vs 47.6 ± 12.0%, p = .02). QRS duration was positively associated with LVEDV (r = 0.49, p < .001) and LVESV (r = 0.47, p < .001), and was inversely associated with LVEF (r= -0.32, p < .001). Multivariate analysis showed that male sex (β = 0.22, p = .04), QRS duration (β = 0.34, p = .002) and number of abnormal Q waves (β = 0.37, p < .001) were associated with LVEDV. QRS duration (β= -0.32, p = .003) and number of abnormal Q waves (β = -0.40, p < .001) were associated with LVEF.

CONCLUSIONS

Our results suggest that QRS duration as well as number of abnormal Q waves is independently associated with LV volume and ejection fraction after anterior MI.

Early changes in left ventricular volume and function are predictors for long-term remodeling in patients with acute transmural myocardial infarction and preserved systolic function

BACKGROUND

We sought to describe the degree of long-term left ventricular (LV) remodeling after acute transmural myocardial infarction with preserved LV systolic function, and to evaluate whether Doppler echocardiographic parameters in the early phase could predict this process.

METHODS

A total of 60 patients without heart failure and with LV ejection fraction > or = 0.40 (mean 0.48 +/- 0.054), were followed up with Doppler echocardiographic examinations at baseline, 3 months, and 1 and 2 years.

RESULTS

There was a significant increase in LV end-diastolic volume index of 7% (P =.006) and LV end-systolic volume index of 8% (P =.03), and no change in ejection fraction. This remodeling was confined to 7 patients (12%) with a significant increase in LV end-diastolic volume index above 20 mL/m(2). There was also a significant increase in the deceleration time of both the early mitral filling wave (Delta early mitral filling wave = 58 milliseconds, P <.0005) and the diastolic forward component of pulmonary venous flow (Delta diastolic forward component of pulmonary venous flow = 61 milliseconds, P <.0005), and a shift in filling pattern with increasing prevalence of abnormal relaxation. Changes in end-diastolic volume index were predicted by baseline early mitral filling wave less than 100 milliseconds, but the most powerful predictors of 2-year remodeling were volume changes at 3 months.

CONCLUSION

Twelve percent of patients with Q-wave infarction and ejection fraction > or = 0.40 experienced significant LV dilatation at 2 years, and this late remodeling was partly related to baseline filling characteristics.