Global and regional left ventricular response to bicycle exercise in coronary artery disease

Berger, Harvey J.; Reduto, Lawrence A.; Johnstone, David E.; Borkowski, Henry; Sands, Jane; Cohen, Lawrence S.; Langou, Rene A.; Gottschalk, Alexander; Zaret, Barry L.

doi:10.1016/0002-9343(79)90476-5

Cited by 225 publications

(25 citation statements)

References 23 publications

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“…However, STsegment displacement on the body surface ECG is not specific for ischemia,' and both false-negative and false-positive ECG findings during exercise testing for detecting coronary artery disease have been reported.2 In the experimental setting, regional wall function dynamics are highly sensitive to local ischemia both at rest5 and during exercise in the conscious dog;6 in clinical studies, simultaneous recordings of ventricular function using radionuclide angiographic techniques and ECG recordings during exercise have suggested superiority of mechanical over electrical events for the detection of temporary myocardial ischemia. [7][8][9] Nevertheless, the exercise test with ECG recordings is still the most popular and economical screening test for coronary artery disease in man, 4 1' and further understanding of the relations between electrical and mechanical events during ischemia is needed. Smith et al, 1' using openchest dogs, reported that endocardial ST-segment elevation may be a more sensitive index of ischemia than depression of myocardial contractile function, but the surface ECG was not recorded.…”

mentioning

confidence: 99%

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Battler¹,

Froelicher²,

Gallagher³

et al. 1980

Circulation

147

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SUMMARY The relations between regional ventricular function and regional and surface ECGs were studied in eight conscious dogs during complete and partial coronary obstructions. Wall thickness and local ECGs were measured using an implanted sonomicrometer, and 11 subcutaneous electrodes were implanted in a modified McFee vectorcardiographic array. Complete obstruction of the circumflex coronary artery (using a hydraulic occluder) produced regional hypokinesia after 15 seconds and regional dyskinesia at 1 minute. Significant ECG changes occurred first in the surface vectorcardiogram, ST segments changed at 30 seconds and mean epicardial and endocardial ECG ST segments increased after 1 minute. During mild partial coronary stenosis that produced stable reductions of systolic wall thickening (%AWT) of less than 25% of control, no ST-segment changes occurred in the surface vectorcardiogram during the 10-minute study period, although ST segments increased significantly in the endocardial and epicardial ECG. With moderate coronary stenoses that produced immediate 25-48% reductions of %AWT (average reduction 36 ± 4%), significant mean ST displacements occurred after 2 minutes in the endocardial ECG, after 3 minutes in the epicardial ECG and after 4 minutes in the surface vectorcardiogram. With coronary stenoses that produced more than 50% reduction of %A.WT (average reduction 69 ± 2%), mean endocardial ST-segment changes were noted after 2 minutes, and changes in both the mean epicardial ECG and the surface vectorcardiogram occurred after 3 minutes. Thus, during mild coronary stenosis, regional myocardial dysfunction can occur without surface ECG changes, while during moderate coronary stenosis, it occurs before endocardial ST-segment changes and precedes surface ECG alterations by several minutes. The surface ECG was slightly more sensitive than the local ECG during complete coronary occlusion and less sensitive during partial coronary obstruction. We conclude that regional contractile abnormalities provide a more sensitive indicator of ischemia than electrocardiographic ST-segment changes.REGIONAL VENTRICULAR dysfunction and STsegment displacement on the ECG are valuable indicators of myocardial ischemia. However, STsegment displacement on the body surface ECG is not specific for ischemia,' and both false-negative and false-positive ECG findings during exercise testing for detecting coronary artery disease have been reported.2 In the experimental setting, regional wall function dynamics are highly sensitive to local ischemia both at rest5 and during exercise in the conscious dog;6 in clinical studies, simultaneous recordings of ventricular function using radionuclide angiographic techniques and ECG recordings during exercise have suggested superiority of mechanical over electrical events for the detection of temporary myocardial ischemia.7-9 Nevertheless, the exercise test with ECG recordings is still the most popular and economical screening test for coronary artery disease in man, 4 1' and further understanding of ...

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mentioning

confidence: 99%

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Battler¹,

Froelicher²,

Gallagher³

et al. 1980

Circulation

147

View full text Add to dashboard Cite

show abstract

“…Separate comparisons were conducted for subgroups categorized according to time of operation (early versus late) and relative ischemia severity at baseline. We used the Cox proportional hazards model 30 to evaluate differences in the relative hazard of major cardiac events among the medicaltreatment-only versus CABG subgroups by stratifying the population according to 3 ranges of baseline ischemia severity, defined as 10% increments in ⌬LVEF (ie, twice the published standard error of the LVEF determination 31 ) around our median ⌬LVEF value. Finally, log-rank test comparison of Kaplan-Meier survival curves was performed to screen baseline variables for their univariate relation to initial cardiac event (death or nonfatal MI) in the expanded-medicaltreatment subgroup; again, censoring occurred at documented noncardiac deaths and revascularizations.…”

Section: Discussionmentioning

confidence: 99%

Prognostication in 3-Vessel Coronary Artery Disease Based on Left Ventricular Ejection Fraction During Exercise

et al. 1999

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Background —Previous data indicate that left ventricular ejection fraction (LVEF) provides prognostic information among patients with coronary artery disease (CAD), but the value of such testing specifically for defining benefits of coronary artery bypass grafting (CABG) may relate to severity of exercise-inducible ischemia measured noninvasively before surgery. Methods and Results —To determine the independent prognostic importance of preoperative ischemia severity for predicting outcomes of CABG among patients with extensive CAD, we monitored 167 stable patients with angiographically documented 3-vessel CAD (average follow-up of 9 years in event-free patients) who previously had undergone rest and exercise radionuclide cineangiography. Their course was correlated with data obtained during initial radionuclide testing, coronary arteriography, and clinical evaluation at study entry. Fifty-two patients received medical treatment only, and 115 underwent CABG (44 early [≤1 month after initial study]). Multivariate Cox model analysis indicated that change (Δ) in LVEF from rest to exercise during radionuclide study was the strongest independent predictor of major cardiac events ( P =0.003) before surgery and also predicted magnitude of CABG benefit ( P =0.04). Patients with ΔLVEF −8% or less derived significant survival-prolonging and event-reducing benefit from CABG performed ≤1 month after initial testing ( P <0.02 for cardiac death and P =0.008 for cardiac events], early CABG versus medical-treatment-only patients); similar benefits were absent among patients with ΔLVEF more than −8%, and among those in whom CABG was deferred. Conclusions —Assessment of ischemia severity based on LVEF response to exercise enables effective prognostication among patients with 3-vessel CAD and defines the likelihood of life-prolonging and event-reducing benefits from CABG.

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“…Each occlusion was produced by inflating an occluder with air and was relieved by deflating. During occlusion, 3 min was allowed for stabilization of the ischemic state, 5 min for each of two RVG and 5 min f'or obtaining the CVG prior to release of the occlusion. At least 20 min was allowed between occlusions and prior to the final control measurements.…”

Section: Methodsmentioning

confidence: 99%

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

Kronenberg¹,

Born²,

Smith³

et al. 1981

J. Clin. Invest.

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A B S T R A C T Radionuclide and contrast ventriculography were evaluated for their ability to estimate myocardial ischemia. In 14 closed-chest, sedated dogs, a small and larger region of ischemia were produced by inflating balloon occluders on the left anterior descending coronary artery. The systemic arterial pressure, atrial-paced heart rate, global ejection fraction by radionuclide and contrast ventriculography, regional wallmotion abnormalities (as the percentage of abnormally contracting segments), and regional myocardial blood flow (using the microsphere technique) were measured during an initial control period, two separate ischemic periods, and a final control period. The regional ischemic weights based on myocardial blood flow ranged from 0 to 38.5 g and were grouped as zero, small (range 0 to <10 g, mean 3.40 g), and large regions of ischemia (>10 g, mean 24.8 g). Regional wall-motion abnormalities were sensitive qualitative indicators of ischemia. Receiver operating characteristic analysis showed that both ventriculographic methods were highly sensitive, specific, and accurate for detecting regional ischemia. Contrast 1370detecting small regions <4 g, but the methods were equal for regions >4 g. The arterial pressure and heart rate were unchanged during ischemia. For small regions of ischemia, the global ejection fraction did not fall using either the contrast or radionuclide technique, but it fell significantly when large regions were produced. There was a quantitative relationship between the percentage ofabnormally contracting segments and the grams of myocardial ischemia (for radionuclide ventriculography, r = 0.65, P = 0.003, and for contrast ventriculography, r = 0.75, P< 0.001), but for many small regions of ischemia, wall-motion changes were greater than anticipated, suggesting hypofunction of the continguous normal tissue.This study demonstrated that both radionuclide and contrast ventriculography were quite sensitive and specific for detecting measured amounts of regional ischemia. The functional changes resulting from ischemia are quantitatively related to the extent of regional ischemia, small areas resulting in regional wall motion abnormalities, and large areas producing both reduced global ejection fraction and wall motion changes.

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Global and regional left ventricular response to bicycle exercise in coronary artery disease

Cited by 225 publications

References 23 publications

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Dissociation between regional myocardial dysfunction and ECG changes during ischemia in the conscious dog.

Prognostication in 3-Vessel Coronary Artery Disease Based on Left Ventricular Ejection Fraction During Exercise

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

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