Left ventricular function in chronic obstructive lung disease

Echocardiographic profiles of the long-term cardiac changes in cystic fibrosis

In this echocardiographic study, assessment of the heart in children with cystic fibrosis has shown that changes occur in not only the right ventricle but also in the left ventricle and aorta, as compared with normal. Echocardiograms could be successfully performed in 34 of 37 patients. The thickness of the right ventricular anterior wall and the dimension of the right ventricular cavity were abnormal, even in patients with mild disease (National Institutes of Health [NIH] score for severity of disease of 85 or greater). Larger, older children with lower NIH score had disproportionately larger right ventricular anterior walls and cavities. The thickness of the septal wall, the thickness of the left ventricular posterior wall, and the aortic dimensions were increased in those with severe disease. The dimensions of the left ventricular cavity for the population were slightly but significantly smaller than normal in systole and in diastole throughout the course of the disease. This study demonstrates that echocardiography is an effective noninvasive means of assessing the long-term changes in children with cystic fibrosis. These changes occur in both sides of the heart and appear to worsen as the disease progresses.

Left ventricular function in chronic obstructive pulmonary disease

The presence or absence of left ventricular dysfunction in chronic obstructive pulmonary disease has been debated for decades. I have reviewed the following evidence pertaining to this topic: (1) left ventricular pathologic abnormalities; (2) the methods used to determine left ventricular performance; (3) specific abnormalities of left ventricular function as revealed by systolic time intervals, left ventricular end-diastolic pressure, ejection fraction, isovolumic indices, and left ventricular function curves; and (4) pertinent experimental data. The bulk of the evidence indicates that the clinical symtoms of left-sided failure are unreliable in those with obstructive disease of the airways and that the great majority of patients have normal left ventricular function, once other causes are excluded. A small group of patients have some abnormalities in left ventricular performance, but these have not been clinically significant. The ultimate importance of such abnormalities awaits future investigation.

Cardiac disease in the wheezing child

Cardiac and pulmonary disease are so closely interrelated that it is often difficult to determine in young infants which is the primary offender. As illustrated in these case reports, failure to recognize the true nature of the disease process may lead to unnecessary procedures and delays which can be life-threatening. Statistically, the wheezing infant very likely is suffering from primary pulmonary disease; however, congenital cardiac abnormalities can cause pulmonary symptoms which completely dominate the clinical picture and lead to erroneous diagnoses. Although rare, the basis of cough and wheezing may be a vascular ring which encircles and compresses the trachea. Lesions associated with large left-to-right shunts, such as ventricular septal defect and patent ductus arteriosus, also can cause cough and wheezing because of bronchial compression by a large tense pulmonary artery and a distended left atrium. These same lesions also produce isolated left ventricular failure with pulmonary venous congestion and episodes of cough and wheezing. Anomalous pulmonary venour return, cor triatriatum, supravalvular mitral ring, or mitral stenosis are other lesions which can cause cough and wheezing secondary to pulmonary venous obstruction.

Effect of dextran loading on left ventricular performance in chronic obstructive pulmonary disease

The status of left ventricular function in patients with chronic obstructive pulmonary disease remains controversial. With a radionuclide technique left ventricular ejection fraction, left ventricular end-diastolic volume, cardiac output, and stroke volume were measured at rest and following infusion of dextran in 23 men with severe COPD. Resting, mean LVEF was normal in 19 subjects with COPD alone; four with COPD and coronary artery disease had a depressed mean LVEF. Left ventricular end-diastolic volume index and pulmonary capillary wedge pressure were both normal at rest indicating that the left ventricle was not volume underloaded. There was a normal response to dextran infusion (750 ml.) with no deterioration in LVEF and a significant increase in cardiac index, stroke volume index, LVEDVI, and PCW. These data suggest that at rest and following volume loading with dextran left ventricular function is normal in patients with COPD.

Symptomatic and puomonary response to acute phlebotomy in secondary polycythemia

A double-blind study of the effects of phlebotomy was carried out in 18 patients with polycythemia secondary to severe hypoxemic lung disease. Eleven subjects underwent a single phlebotomy of 10 percent of their blood volume, and eight patients serving as controls underwent a sham procedure. Eight of the phlebotomized subjects, but none of the controls, reported subjective clinical improvement (P less than 0.005). Subjects who noted improvement after venesection had higher hematocrit readings than those who did not (P less than 0.02). Symptomatic relief seemed to be most dramatic in those with clinical evidence of congestive heart failure. In contrast to this clear-cut subjective improvement, phlebotomy did not alter objective indices of airway obstruction, lung elastic recoil, pulmonary gas exchange, or exercise tolerance in either the phlebotomized or the control group. Thus, although phlebotomy produced subjective benefit in the majority of patients studied, it was not associated with objective improvement in lung function or exercise tolerance.

Evaluation of left ventricular performance in acutely ill patients with chronic obstructive lung disease

Among 28 patients with chronic obstructive pulmonary disease (COPD) with increasing dyspnea, the resting mean pulmonary arterial wedge pressure was elevated (greater than 12mm Hg) in 4 and became abnormal with exercise in 3 other subjects. Stroke volume index was reduced (less than 36 ml/beat/M2) in 16 of 26 patients (62 percent). The resting pre-ejection period index was prolonged (greater than 144 msec) in 17 patients (65 percent), while the left ventricular (LV) ejection time index was reduced (less than 408 msec) in 23 patients (88 percent). The ratio of the pre-ejection period to the LV ejection time was within the normal range (0.309 to 0.381) in only 3 of 26 patients (12 percent). Echocardiographic measurements of LV function were normal in nine patients, seven of whom had one or more abnormal values for systolic time intervals (STIs). These data suggest that reduced LV filing results in abnormal values for STIs in patients with COPD, and therefore that in such patients STIs are not accurate indices of LV function.

An analysis of the physiological strain of submaximal exercise in patients with chronic obstructive bronchitis

An increasing work rate was performed by 40 patients with chronic obstructive bronchitis, split into two groups according to FEV1 (group M, mean FEV1 1-451. and group S, mean FEV1 0-621.), and by 20 normal, non-athletic men of similar age to the patients. Values for cardiac frequency and ventilation were interpolated to standard oxygen uptakes of 0-75, 1-0, and, where possible, 1-5 min-1. The tidal volume at a ventilation of 20 and 30 1 min-1 was also determined. The cardiac frequencies at oxygen uptake of 0-75 and 1-01 min-1 were significantly higher in the patient groups than in the normal men, and were highest in patient group S. The cardiac output when related to the oxygen uptake was in the normal range in all three groups of subjects, so that the patients had smaller stroke volumes than the normal men. Ventilation at oxygen uptakes of 0-75 and 1-01 min-1 was significantly higher in both patient groups than in the normal subjects; there were no significant differences between the two patient groups, Values for dead space/tidal volume ration, alveolar-arterial oxygen gradient, and the percent venous admixture measured during a constant work rate test were significantly greater than normal in the patient groups. Possible factors limiting exercise tolerance in these patients were assessed by extending the increasing work rate test from submaximum to maximum exercise. Changes in blood gas tensions and blood lactate concentrations from resting levels were small, and probably did not limit exercise performance. Measurements at maximum exercise did not add appreciably to the analysis of the disturbed cardiopulmonary function. This study has shown that major disturbances in cardiopulmonary function can be demonstrated without the need for stressing a patient to the limit of his effort tolerance.

Left ventricular ejection fraction in severe chronic obstructive airways disease

The subject of left ventricular involvement in chronic obstructive airways disease is controversial. We measured left ventricular ejection fraction (LVEF) in 120 patients with severe chronic obstructive airways disease, 92 of them acutely decompensated and 28 stable. A bedside radionuclide technic using a scintillation probe was used to measure LVEF. Of the 28 patients with acute respiratory failure, LVEF was normal (larger than or equal to 55 per cent) in 60 and subnormal in 32. Of the 28 patients with stable chronic obstructive airways disease, LVEF was normal in 12 and low in 16. Coronary artery disease could be demonstrated clinically or at autopsy in 13 of the patients with acute and in 7 of the patients with stable chronic obstructive airways disease. LVEF was 28 plus or minus 10.4 per cent (average plus or minus SEM) in the patients with acute chronic obstructive airways disease and coronary artery disease which was significantly different (P smaller than 0.001) from LVEF in patients without coronary artery disease (61 plus or minus 1.9 per cent). In the patients stable with chronic obstructive airways disease and coronary artery disease, LVEF was (42 plus or minus 3.5 per cent), significantly different (P smaller than 0.001) from LVEF in those without coronary artery disease (55 plus or minus 2.1 per cent). There was no relationship between LVEF and arterial oxygen, or carbon dioxide tension, or pH. Results suggest that LVEF is normal in patients with severe lung disease alone and that reduced LVEF in patients with chronic obstructive airways disease can reasonably be ascribed to coronary artery disease.

Systolic time intervals in chronic obstructive pulmonary disease

In an attempt to clarify the relationship between left ventricular function and chronic obstructive pulmonary disease (COPD), systolic time intervals (STI) were measured in 12 control subjects and 28 patients with COPD who had only moderate arterial blood gas abnormalities and who had no cardiac symptomatology or clinical evidence of organic heart disease. The patients with COPD were divided into three groups of increasingly severe airway obstruction based on the percent predicted forced expired volume in one second.

Significant differences in pre-ejection period index (PEP 1 ) and left ventricular ejection time index (LVET 1 ) existed between the control subjects and the patients with the most severe lung disease (Group III). A highly significant difference in PEP/LVET existed between these two groups. The abnormalities of STI demonstrated in these patients are characteristic of left ventricular dysfunction and indicate that subclinical left ventricular dysfunction is frequently present in patients with moderate obstructive lung disease.

Left ventricular function, metabolism, and blood flow in chronic cor pulmonale

Left ventricular function, oxidative metabolism, and coronary blood flow were evaluated in 11 patients with chronic cor pulmonale (mean age 53 years) at rest and during stress, and compared with 11 normal subjects (mean age 29 years) studied under similar conditions. The left ventricles of patients with chronic cor pulmonale were normal in regard to contractile state, preload, afterload, coronary blood flow, and myocardial oxidative metabolism. However, the mean cardiac index, stroke volume, stroke work, and left ventricular ejection fraction were below normal, and end-systolic volume was elevated. These differences in performance are consistent with the older mean age of the patients. An alternative explanation is the limit placed on right ventricular stroke volume by the increased afterload (pulmonary vascular resistance). Allowance for these factors permits the conclusion that the left ventricles of patients with chronic cor pulmonale are normal unless involved by a second disease process.