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[The analysis of left ventricular filling dynamics by radionuclide ventriculography using ECG's R wave and the second
Insights
Coronary artery disease (CAD) impairs early diastolic left ventricular (LV) filling. Atrial contraction compensates for this in patients without prior myocardial infarction (MI), but not in those with prior MI.
Area of Science:
- Cardiology
- Cardiac Physiology
- Diagnostic Imaging
Background:
- Coronary artery disease (CAD) can lead to impaired left ventricular (LV) filling.
- Understanding diastolic dysfunction is crucial for managing CAD patients.
- The role of atrial contraction (AC) in compensating for impaired LV filling in CAD requires further investigation.
Purpose of the Study:
- To assess early diastolic LV filling impairment in CAD patients.
- To evaluate the effect of atrial contraction (AC) on total LV filling in CAD.
- To compare LV filling dynamics in normal individuals and CAD patients with and without prior myocardial infarction (MI).
Main Methods:
- Equilibrium radionuclide ventriculography (ERNV) was used to study LV volume (LVV) changes.
- Data acquisition included list-mode, R-wave, and S2 markers for precise timing.
- LVV curves were analyzed for systolic and diastolic phases, including rapid filling (RF) and atrial contraction (AC) phases.
Main Results:
- Early diastolic filling (PFR-RF, FF) was reduced in CAD patients (CAD-1 and CAD-2) compared to normals.
- Systolic function (EF, PER) was significantly impaired only in CAD patients with prior MI (CAD-2).
- Atrial contraction (AC/SV) compensated for impaired early filling in CAD-1 patients but not in CAD-2 patients.
Conclusions:
- Impaired early diastolic LV filling precedes systolic dysfunction in CAD.
- Atrial contraction can compensate for reduced early diastolic filling in CAD patients without prior MI.
- In CAD patients with prior MI, impaired early filling is not compensated by atrial contraction, likely due to elevated LV filling pressures.
Abstract:
To assess the impairment of early diastolic left ventricular (LV) filling and the effect of atrial contraction on total LV filling in patients (pts) with coronary artery disease (CAD), LV volume (LVV) changes during rapid filling (RF) and atrial contraction (AC) phases were studied by equilibrium radionuclide ventriculography in 10 normals (N) and 17 pts with CAD including eight without (CAD-1) and nine with (CAD-2) previous myocardial infarction (MI). The data were acquired in a list-mode fashion as a series of X, Y coordinates, time markers and an ECG's R wave (R) plus the second heart sound (S2) markers. LVV curves were obtained from three types of multi-gated images by (1) R-synchronized forward reformatting for the analysis of systolic phase (ejection fraction; EF and peak ejection rate; PER), (2) S2-synchronized forward reformatting for the analysis of RF phase (peak filling rate; PFR-RF and filling fraction; FF) and (3) R-synchronized backward reformatting for the analysis of AC phase (peak filling rate; PFR-AC and LVV increment with atrial contraction/stroke volume; AC/SV). EF and PER were significantly lower (p less than 0.001) in CAD-2 (36.0 +/- 8.1% and -1.5 +/- 0.4 EDV/sec) than in N (58.2 +/- 5.8% and -2.4 +/- 0.4 EDV/sec), but those in CAD-1 (52.7 +/- 6.4% and -2.2 +/- 0.3 EDV/sec) were almost the same as N. However PFR-RF and FF were reduced both in CAD-1 (1.5 +/- 0.4 EDV/sec and 23.0 +/- 7.0%) and CAD-2 (1.3 +/- 0.4 EDV/sec and 19.0 +/- 8.0%) compared with N (2.3 +/- 0.4 EDV/sec and 37.0 +/- 8.3%). PFR-AC and AC/SV were significantly greater (p less than 0.01) in CAD-1 (1.3 +/- 0.3 EDV/sec and 0.30 +/- 0.06) than N (0.8 +/- 0.3 EDV/sec and 0.13 +/- 0.07), but those in CAD-2 (0.6 +/- 0.4 EDV/sec and 0.18 +/- 0.09) showed no increase like in CAD-1. These results indicate that 1) the impairment of early diastolic filling precedes the evidence of systolic dysfunction in pts with CAD and 2) AC could compensate the impaired early filling in pts without prior MI, whereas in pts with prior MI this compensatory mechanism is absent presumably because of elevated LV filling pressure.