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Minor segmental dyssynergy reflects extensive myocardial damage and global left ventricle dysfunction in chronic
Oswaldo César de Almeida-Filho1, Benedito Carlos Maciel, André Schmidt
1Division of Cardiology, Department of Internal Medicine, University Hospital, Medical School of Ribeirão Preto, University of São Paulo, Brazil.
Insights
Chagas disease (ChD) patients, even in the indeterminate form (IF), show impaired left ventricular (LV) systolic performance. The end-systolic pressure-dimension (P(es)-D(es)) slope is reduced, indicating subclinical myocardial damage in Chagas disease.
Area of Science:
- Cardiology
- Infectious Diseases
- Physiology
Background:
- Chagas disease (ChD) often presents with an indeterminate form (IF) characterized by positive serology but no clinical symptoms or signs of cardiac involvement.
- Subclinical impairment of left ventricular (LV) systolic performance may precede overt cardiac manifestations in Chagas disease patients.
- Assessing LV contractility is crucial for early detection and management of ChD-related cardiac complications.
Purpose of the Study:
- To investigate subclinical left ventricular (LV) systolic performance in patients with Chagas disease (ChD), including the indeterminate form (IF).
- To evaluate the left ventricular end-systolic pressure-dimension (P(es)-D(es)) relation as an index of contractility in different ChD clinical forms.
- To determine if minor segmental wall motion abnormalities (SWMAs) in ChD patients correlate with more severe myocardial impairment.
Main Methods:
- Studied 35 Chagas disease patients (14 IF, 11 digestive form [DF], 10 cardiac form [CF]) and 13 healthy controls.
- Measured LV dimensions via echocardiography and LV end-systolic pressure (P(es)) using carotid pulse tracings at rest and during phenylephrine infusion.
- Assessed LV contractility using the P(es)-D(es) slope, percent fractional shortening (%DeltaD), and rate-corrected mean velocity of fiber shortening (Vcf(c)).
Main Results:
- %DeltaD and Vcf(c) did not significantly differ between ChD groups and controls, even under stress.
- The P(es)-D(es) slope was significantly reduced in all ChD patient groups (IF, DF, CF) compared to healthy subjects.
- Chagas disease patients with minor segmental wall motion abnormalities exhibited a markedly depressed P(es)-D(es) slope, suggesting more extensive myocardial damage.
Conclusions:
- The P(es)-D(es) slope is a sensitive index of impaired LV systolic performance in Chagas disease, even in the indeterminate form.
- Standard echocardiographic parameters (%DeltaD, Vcf(c)) may not detect early systolic dysfunction in Chagas disease.
- Chagas disease patients with minor wall motion abnormalities show evidence of significant subclinical myocardial damage and may represent an early cardiac form.
Abstract:
The majority of patients with Chagas disease (ChD) remain for 10 to 30 years or even for life in the indeterminate form (IF) of this disease. They have positive-specific serology tests for ChD, but no symptoms or physical signs, and normal findings for electrocardiograms (ECGs) and heart, esophagus, and colon radiographs. To investigate whether patients in this phase of disease have any impairment of left ventricular (LV) systolic performance, we assessed their contractility index by the slope of the LV end-systolic pressure-dimension (P(es)-D(es)) relation. We studied 35 patients with ChD (14 IF, 11 digestive form [DF], 10 cardiac form [CF]) and 13 healthy subjects. Patients with the CF had only minor cardiac involvement (bundle-branch block, normal LV ejection fraction). All patients had normal baseline global LV systolic function on 2-dimensional echocardiography, but minor segmental wall motion abnormalities were observed in 3 DF, 3 IF, and 2 CF patients. At rest and during intravenous phenylephrine infusion, we measured LV dimensions by echocardiography, and LV end-systolic pressure was estimated by a calibrated carotid pulse tracing. We also measured percent fractional shortening (%DeltaD) and the rate-corrected mean velocity of fiber shortening (Vcf(c)). Mean values (+/- SD) of %DeltaD and Vcf(c) were not significantly different from those exhibited by healthy control subjects in any of the ChD groups at rest (except for CF) or at peak stress using phenylephrine. The P(es)-D(es) slope was similarly and significantly reduced in all ChD patients (IF: 50.7 +/- 25; DF: 52.3 +/- 24; CF: 60.8 +/- 22 mm Hg/cm) compared with normal subjects (89 +/- 17 mm Hg/cm). The P(es)-D(es) slope was even more depressed (39.6 +/- 10 mm Hg/cm) in ChD patients who had minor segmental wall motion abnormalities (SWMAs) on the baseline 2-dimensional echocardiograph in comparison with the slightly reduced values found in patients with CF who had isolated conduction abnormalities on the ECG (71.8 +/- 10 mm Hg/cm). Although %DeltaD and Vcf(c), even at peak afterload, do not differentiate ChD patients from normal controls, the P(es)-D(es) slope is significantly impaired in IF, DF, and CF patients. The remarkably lower P(es)-D(es) slope value documented in ChD patients exhibiting only minor LVWMAs suggests a more extensive myocardial damage in this group of patients, indicating that they should be considered as exhibiting symptoms of the CF version of the disease.