The use of single plane angiocardiograms for the calculation of left ventricular volume in man

SUMMARY Two hundred men with normal ECGs at rest had maximum treadmill tests using 14 The diagnostic impact of maximal treadmill testing using 14 ECG leads is greatest in men with typical and probable angina. In these two clinical subsets the presence or absence of horizontal or downsloping ST-segment depression 1 mm, ST-segment elevation > 1 mm, or a slowly upsloping ST-segment depression > 2 mm at 0.08 seconds after the J point in any of 14 leads is highly predictive of multivessel disease when used in conjunction with treadmill work time. The predictive value of maximal treadmill testing using 14 ECG leads in men with nonspecific chest pain is less useful. The lower predictive value of a positive test occurs because this clinical subset has less severe coronary disease and a lower prevalence of disease than men with anginal symptoms. Recording a single lead such as CM, would suffice for the majority of patients in this subset using either horizontal or downsloping ST-segment depression 2 1 mm or ST-segment elevation > 1 mm as criteria for positivity.THE SENSITIVITY AND EFFICIENCY of maximal treadmill testing in men with angina pectoris can be increased by recording multiple ECG leads and combining the results with physiological data collected during exercise." 2 Little information is available on multiple-lead exercise testing in subsets of patients with a lower disease prevalence, such as asymptomatic patients, those with nonspecific chest pain, and women. Several investigators have reported decreased specificity of exercise test results in selected populations with a low disease prevalence.3-5 There is concern that the use of multiple ECG leads could increase the false positive rate in this type of population.

Section: Detection Of High-risk Lesionsmentioning

confidence: 92%

The importance of clinical subsets in interpreting maximal treadmill exercise test results: the role of multiple-lead ECG systems.

Chaitman¹,

Waters²,

Bourassa³

et al. 1979

“…[1][2][3][4][5][6][7][8][9] In addition, the effects of coronary artery disease on left ventricular performance have also been extensively studied. '0-"5 In contrast, much less attention has been given to the performance of the right ventricle in either normal subjects or patients with coronary artery disease.…”

mentioning

confidence: 99%

Right ventricular performance in patients with coronary artery disease.

Ferlinz¹,

Gorlin²,

Cohn³

et al. 1975

175

While left ventricular (LV) performance in patients with coronary artery disease (CAD) has been extensively investigated, little attention has been given to right ventricular (RV) function in this disease. For this purpose, a new geometric model for RV volume has been developed and RV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), stroke volume index (SVI) and ejection fraction (EF) have been determined from biplane RV cineangiograms in 26 patients.Eight patients served as normal (control) subjects (group I). Eighteen patients with obstructive CAD comprised two other groups: six who had no significant disease of the right coronary artery (RCA) (group II) and 12 who had a high grade RCA lesion (group III). The mean values for EDVI, SVI and EF in group I were 76 ± 11 ml/m2, 50 ± 6 ml/m2, and 66 ± 6%. The only significant difference between groups I and II was that SVI was lower in group II tha.n in group I (P < 0.01). No measurements in groups II and III were statistically different from each other. However, markedly subnormal values were found in group III (EDVI: 61 ± 16 ml/m2, SVI: 33 ± 10 ml/m2 and EF: 52 ± 7%); all values being significantly lower (SVI and EF: P < 0.001; EDVI: P < 0.05) than in group I. RV end-diastolic pressure was normal in all patients. These findings may be related to 1) reduced RV compliance, 2) distorted LV geometry, 3) possible RV ischemia or 4) reduced Frank-Starling effect.LEFT VENTRICULAR GEOMETRY, volume and contractile parameters in normal hearts have been analyzed in great detail within the last 15 years.1-9 In addition, the effects of coronary artery disease on left ventricular performance have also been extensively studied.'0-"5 In contrast, much less attention has been given to the performance of the right ventricle in either normal subjects or patients with coronary artery disease. This has been due partially to the fact that the left ventricle was always considered the more important chamber of the heart. The relative neglect of right ventricular performance has been further compounded by difficulties in analyzing the geometry of the right ventricular chamber: while the left ventricular configuration approximately resembles an ellipsoid of revolution (and therefore renders itself to relatively simple mathematical analysis), the right ventricle has always been considered a somewhat Autopsied intact human hearts of various sizes without any significant gross abnormalities were used to prepare casts. A silicone disk, fitted with a cannula for injection of plastic compound, was sutured into the tricuspid valve orifice. The pulmonary artery was clamped just above the pulmonary valve. Dow-Corning Silastic A-RTV Mouldmaking Rubber treated with RTV-4 catalyst was then injected through the cannula. Filling pressure was maintained at approximately 15 cm H20. The filled heart was then suspended by sutures from a small stand, and the compound inside the right ventricle allowed to harden in this suspended state in order to minimize any potential distortion of the ri...

“…The electrocardiograms returned to normal in nine patients with three vessel disease in less than 1 min whereas ten patients were still positive 5 min after exercise. Of six 14 Four of the six were false positives and one patient each had one and two vessel disease respectively. Among these 23 men, 12 were unable to complete Bruce stage I.…”

Section: Exercise Capacitymentioning

confidence: 97%

“…The patient population in this study was The exercise test was most useful when 14 leads were used and other parameters were evaluated such as 1) the time ischemia first appeared, 2) the pressure-rate product at the time that ischemia first appeared, and 3) the maximum exercise capacity that could be attained. These physiological responses to exercise were valuable parameters when used in conjunction with the multiple lead ECG since they greatly improved the predictive value of the test in finding multivessel disease.…”

Section: Exercise Capacity and Detection Of Multivessel Diseasementioning

confidence: 99%

Improved efficiency of treadmill exercise testing using a multiple lead ECG system and basic hemodynamic exercise response.

Chaitman¹,

Bourassa²,

Wagniart³

et al. 1978

187

SUMMARY One hundred consecutive men with a normal ECG at rest had a maximal treadmill test using 14 leads during and postexercise. Coronary arteriography performed the following day revealed coronary stenoses k70% in 66 patients. Test results obtained from a V6 lead were compared to different lead combinations and were correlated with arteriographic findings. A positive exercise test occurred in 37 men using an isolated V, lead compared to 50 men (P < 0.05) using 11 leads, 52 men (P < 0.05) using a combined CM6, CC5, Cl (inferior) lead system and 58 (P < 0.001) men using all 14 leads. The predictive value of a positive test varied between 89-95% and was not changed significantly by the addition of multiple leads. The 14 lead ECG was positive in 43/45 (96%) patients with mul-THE DIAGNOSTIC VALUE OF EXERCISE TESTING has been criticized and defended in recent editorials.'-Redwood and colleagues' have argued that an increased incidence of false positive tests which occur in an asymptomatic population could result in a needless increase in the number of coronary arteriograms which are being performed. Several studies support his concern.'4 In addition, these investigators state that a good clinical history alone is usually adequate in patients with typical angina pectoris and that exercise testing provides superfluous data. Sheffield et al.2 and McHenry3 have defended the value of exercise testing and state that the ECG response is only one of several parameters which should be examined during an exercise test and that the efficiency of this diagnostic procedure can be maximized if a multiple lead system is used. The optimal number of leads required to achieve maximal sensitivity without reducing the predictive value of a positive test has not been well studied. Therefore, we have compared several combinations of lead systems during exercise testing to coronary arteriographic findings in a consecutive series of 100 men who had a normal resting ECG and no previous history of myocardial infarction. Several physiologic responses to exercise such as treadmill endurance time, heart rate, and systolic blood pressure response, and the duration of exercise required to produce ST-segment depression were also studied to determine their usefulness as predictors of multivessel disease. tivessel disease. Parameters which helped to predict multivessel disease using 14 leads were 1) the time that ischemia first appeared 2) the pressurerate product at the time ischemia first appeared, and 3) the maximum workload that could be attained. In general, the magnitude of STsegment depression and the time required for a positive ECG to return to normal postexercise were not useful predictors of multivessel disease.We conclude that the use of multiple leads improves the sensitivity and efficiency of the maximal treadmill exercise test. The usefulness of exercise test results can be further improved if multiple leads are combined with physiologic data collected during exercise. Methods Patient SelectionMaximal treadmill tests were performed o...