The George E. Brown Memorial Lecture

Diastolic heart failure: a confusing concept

Descriptions of the pathophysiology of heart failure have gone through a substantial evolution in the last 50 years. It is now recognised that heart failure can occur in the presence and also in the absence of a reduction in left ventricular function. In the former situation, this classically has been described to lead to hypotension and secondary salt and volume retention by the kidneys, further aggravating cardiac function. In the latter, this has been described to lead to pulmonary congestion because of impaired cardiac diastolic filling. These concepts have further evolved in the discrimination of 'acute vascular' versus 'acute congestive' heart failure. The current paper builds the argument from numerous smaller observational studies that irrespective of the clinical presentation of heart failure, fluid congestion is the key. If left ventricular function is preserved, fluid retention is probably due to the inability of damaged kidneys to excrete the large amounts of salt ingested with modern diet. In the extreme of end-stage renal disease requiring haemodialysis, heart failure is frequent, but can be prevented almost entirely by strict volume control. Unfortunately, the absence of systematic studies describing fluid volumes and renal haemodynamic and reabsorptive function in patients with acute heart failure precludes the final proof of our concept. This paper therefore is a strong call for mechanistic research in this area.

Unpleasant truths about salt restriction

Most chronic dialysis patients are volume overloaded. This has two consequences. The first is hypertension. Even though the pathophysiologic mechanism causing this blood pressure (BP) elevation is well known, many patients are treated with antihypertensive drugs. These are often ineffective and, even if they lower BP, they do not eliminate its cause and the associated cardiac damage. But at least as harmful to the heart as the pressure load is the volume load. In the early phase of dialysis, this may lead to acute pulmonary edema, which is often erroneously referred to as "heart failure." Later, it causes dilatation of the heart compartments, stretching of their walls, and regurgitation through the valves. This dilated cardiomyopathy eventually leads to liver congestion, decreased ejection fraction, and low blood pressure. It is considered to be irreversible and incorrectly called "uremic" by many authors, but can be markedly improved and even cured by judicious ultrafiltration. This may take many months, since the heart muscle needs time to become "remodeled." All these unwanted effects could be prevented by strong dietary salt restriction. We tried to analyze why this and other "old truths" are being forgotten. While the reasons are clearly multifactorial, the unfortunate introduction of the Kt/V concept seems the most important one. The claim that adequacy of dialysis can be solely defined by urea removal, disregarding all other factors, above all salt retention, has diverted the nephrologist's attention from the most important issue, giving them the false conviction that the prescribed treatment is "adequate."

A case of progressive congestive heart failure secondary to severe anemia in a patient presenting with uterine hemorrhage

In this report, we present a 42-year-old female patient who was transferred to our emergency department due to symptoms of congestive heart failure. She presented with severe anemia (hemoglobin was 1.3 g dl(-1), and hematocrit was 6.0%) due to continuous uterine hemorrhage and metabolic acidosis, otherwise she seemed to be free from illness. We diagnosed that she was suffered from chronic severe anemia due to uterine hemorrhage and congestive heart failure. Monitoring her hemodynamic status, treatment of congestive heart failure using diuretics and inotropes in combination with blood transfusion brought her good recovery. We discussed this case from the mechanisms of development of congestive heart failure in a chronic severe anemic condition, and pointed out that distributive effects of sodium and water may develop congestive heart failure without myocardial dysfunction in such a condition.

How well can the chest radiograph diagnose left ventricular dysfunction?

OBJECTIVES

To review the diagnostic utility of the chest radiograph for left ventricular dysfunction.

DATA SOURCES

Structured MEDLINE searches, citation reviews of relevant primary research, review articles, and textbooks, personal files, and data from experts.

STUDY SELECTION

Studies of patients without valvular disease that allowed calculation of the sensitivity and specificity of selected radiographic signs compared with a criterion standard of increased left ventricular preload or reduced ejection fraction.

DATA EXTRACTION

Two independent readers reviewed 29 studies. Studies were pooled after stratification by radiographic finding, criterion standard, and clinical setting.

MAIN RESULTS

Redistribution best diagnosed increased preload with a sensitivity of 65% (95% confidence interval [CI] 55%, 75%) and specificity 67% (95% CI 53%, 79%). Cardiomegaly best diagnosed decreased ejection fraction with a sensitivity of of 51% (95% CI 43%, 60%) and specificity of 79% (95% CI 71%, 85%). Interrater reliability was fair to moderate for redistribution and moderate for cardiomegaly. The clinical setting affected results by decreasing the specificity of cardiomegaly to 8% in detecting increased preload in patients with severe systolic dysfunction. The absence of redistribution could only exclude increased preload in situations in which the suspicion (pretest probability) of disease was less than 9%, whereas redistribution could confirm increased preload when the pretest probability was greater than 91%. The absence of cardiomegaly could only exclude a reduced ejection fraction if the pretest probability was less than 8%, whereas cardiomegaly could confirm a reduced ejection fraction if the pretest probability was greater than 87%.

CONCLUSIONS

Redistribution and cardiomegaly are the best chest radiographic findings for diagnosing increased preload and reduced ejection fraction, respectively. Unfortunately, neither finding alone can adequately exclude or confirm left ventricular dysfunction in usual clinical settings. Redistribution is not always reliably interpreted.

Pathogenesis of oedema in chronic severe anaemia: studies of body water and sodium, renal function, haemodynamic variables, and plasma hormones

BACKGROUND

Patients with chronic severe anaemia often retain salt and water. Fluid retention in these patients is not caused by heart failure and the exact mechanisms remain unclear. This study was designed to examine some of the possible mechanisms.

METHODS AND RESULTS

Haemodynamic variables, body fluid compartments, renal function, and plasma hormones were measured in four patients with oedema caused by chronic severe anaemia (mean (SE) haematocrit 13 (1.7)) who had never received any treatment. Cardiac output was increased (6.1 (0.6) l/min/m2) and right atrial (7.8 (1) mm Hg), mean pulmonary arterial (20.5 (2.0) mm Hg), and mean pulmonary arterial wedge (13 (2.7) mm Hg) pressures were slightly increased. The mean systemic arterial pressure (81 (1.3) mm Hg) and systemic vascular resistance (12.3 (1.1) mm Hg x min x m2/l were low. There were significant increases in total body water (+14%), extracellular volume (+32%), plasma volume (+70%), and total body exchangeable sodium (+30%). Renal blood flow was moderately decreased (-46%) and the glomerular filtration rate was slightly reduced (-24%). There were significant increases in plasma noradrenaline (2.1-fold), renin activity (15-fold), aldosterone (3.2-fold), growth hormone (6.3-fold), and atrial natriuretic peptide (12-fold).

CONCLUSION

In patients with oedema caused by chronic severe anaemia there is retention of salt and water, reduction of renal blood flow and glomerular filtration rate, and neurohormonal activation similar to that seen in patients with oedema caused by myocardial disease. However, unlike patients with myocardial disease, patients with anaemia have a high cardiac output and a low systemic vascular resistance and blood pressure. It is suggested that the low concentration of haemoglobin in patients with anaemia causes a reduced inhibition of basal endothelium-derived relaxing factor activity and leads to generalised vasodilatation. The consequent low blood pressure may be the stimulus for neurohormonal activation and salt and water retention.

The correlation of cardiac power output to exercise capacity in chronic heart failure

Cardiac haemodynamics are deranged in chronic heart failure but fail to predict the exercise capacity of the patient. Cardiac power output is a descriptor of cardiac function derived from preload, blood pressure and cardiac output. Forty-one patients with moderately severe and severe chronic heart failure were exercised on a cycle ergometer to determine the relationship between traditional haemodynamics and cardiac power output and exercise capacity. Resting cardiac power output was no more predictive of exercise capacity than resting stroke-work index or resting cardiac index (r = 0.53, 0.61 and 0.51 respectively). Maximum cardiac power output and the ability to increase cardiac power output, however, were correlated with exercise capacity (r = 0.79 and 0.80). It is concluded that resting cardiac power output does not predict subsequent exercise capacity but that maximum cardiac power output and the ability to increase cardiac power output on stimulation are good descriptors of functional cardiac reserve.

Thyroid hormone and the cardiovascular system

To understand the pathophysiology of thyroid heart disease, it is necessary to recognize that thyroid hormone has effects on both the peripheral circulation and the myocardium. One of the earliest responses to thyroid hormone administration is a decline in systemic vascular resistance and an increase in cardiac output and cardiac contractility. In many ways, this response is similar to the cardiovascular response to exercise and is associated with increased left ventricular work. The majority of cardiac adaptations to changes in thyroid function are physiologic; however, certain patients do demonstrate clinical evidence of cardiac disease. Atrial arrhythmias, limitations in exercise tolerance, and congestive heart failure are reported to occur as a result of hyperthyroidism and are more common in older patients. Thyroid hormone also plays an important role in the regulation of blood pressure. Diastolic hypertension is a common accompaniment of hypothyroidism. By understanding the mechanisms by which thyroid hormone affects both the peripheral circulation as well as the myocardium, it is possible to predict the clinical response to the treatment of various thyroid disease states.

The effects of controlled oxygen therapy on ventricular function in patients with stable and decompensated cor pulmonale

We made simultaneous measurements of pulmonary hemodynamics, cardiac output, and right ventricular ejection fraction (RVEF) to assess the right ventricular function in 14 patients with pulmonary arterial hypertension as a result of chronic obstructive pulmonary disease (COPD). From these measurements, the right ventricular end-systolic pressure/volume relationship could be calculated and used to assess right ventricular contractility. Eight of the patients were clinically stable, without edema, and 6 presented acutely with gross edema, indicating decompensated cor pulmonale. Measurements were made at rest, while breathing air and oxygen. Although mean pulmonary arterial pressure (Ppa) was similar in those with (Ppa = 33 +/- 6 mm Hg) and without edema (Ppa = 30 +/- 8 mm Hg, p greater than 0.05), RVEF was lower in edematous (RVEF = 0.23 +/- 0.11) compared with non-edematous patients (RVEF = 0.47 +/- 0.04, p less than 0.01). Cardiac output was normal in both groups. The mean right ventricular end-systolic pressure/volume ratio (P/V) was lower in those patients with edema (P/V = 0.41 +/- 0.27), as compared with those without edema (P/V = 1.69 +/- 0.35, p less than 0.05), as a result of an increase in right ventricular end-systolic volume index. Similarly, left ventricular end-systolic volumes were higher in edematous than in non-edematous patients. Breathing 1 to 3 L/min of oxygen for 30 min decreased total pulmonary vascular resistance (p less than 0.05) in those patients without edema, but not in patients with edema. Oxygen did not change RVEF, left ventricular ejection fraction (LVEF), or the ventricular end-systolic P/V relationships.(ABSTRACT TRUNCATED AT 250 WORDS)

A noninvasive comparison of left ventricular performance in sickle cell anemia and chronic aortic regurgitation

Abnormalities of the cardiovascular system are common in patients with sickle cell anemia (SS). Noninvasive testing to document left ventricular dysfunction has yielded conflicting results. Left ventricular performance was evaluated in 27 patients with SS by M-mode and 2-D echocardiography, and systolic time intervals. Comparisons were made to 25 normal controls, and to 22 patients with chronic aortic regurgitation. Left ventricular diastolic diameter (LVDD) and cardiac index (CI) were significantly greater in the patients with SS than in controls (LVDD 5.3 +/- 0.4 vs. 4.7 +/- 0.5 cm; CI 4.2 +/- 1.3 vs. 3.1 +/- 0.8 liters/min/m2; both p less than 0.001). Left ventricular ejection fraction (EF) was slightly, but significantly less (62.9 +/- 7.3 vs. 67.0 +/- 5.4; p less than 0.05). In comparison to the patients with chronic aortic regurgitation, the LVDD in the patients with SS was slightly, but significantly lower (LVDD 5.3 +/- 0.4 vs. 5.9 +/- 0.6 cm; p less than 0.05). There was no significant difference between the patients in EF or CI (EF 62.9 +/- 7.3 vs. 63.3 +/- 4.4; CI 4.2 +/- 1.3 vs. 5.0 +/- 1.0 liters/min/m2; NS). Left ventricular EF was below 55 in three patients who also had hypertension at the time of examination. We conclude that patients with SS have resting left ventricular performance consistent with a high output state. Significant left ventricular dysfunction related to sickle cell disease alone was not demonstrated in this population, although the addition of hypertension appears to deleteriously affect resting left ventricular performance.

Cardiac function in sickle cell anemia

Although ventricular dysfunction is suspected to underlie congestive heart failure in sickle cell anemia (SCA), ejection indexes of left ventricular (LV) pump performance have been found to be normal. The increased preload and decreased afterload of SCA increases the ejection phase indexes and might obscure true LV dysfunction. Therefore, the preload and afterload independent end-systolic stress-volume index was compared in 11 patients with SCA and in 11 normal volunteers. End-systolic pressure and echocardiographic LV dimensions were determined during rest, leg raise, hand-grip and amyl nitrite inhalation. Systemic vascular resistance (afterload) was decreased to 1,033 +/- 314 dynes s cm-5 (mean +/- standard deviation) in SCA from 1,701 +/- 314 dynes s cm-5 in normal subjects. End-diastolic volume index (preload) was increased to 102 +/- 24 ml/m2 in SCA from 66 +/- 10 ml/m2 in normal subjects. Cardiac index was increased to 4.7 +/- 1.1 liters/min/m2 in SCA from 2.8 +/- 0.8 liters/min/m2 in normal subjects. Ejection fractions were similar: 0.59 +/- 0.09 in SCA versus 0.62 +/- 0.07 in normal subjects. However, in patients with SCA, the ratio of resting end-systolic stress-volume index was decreased (1.5 +/- 0.5 in SCA versus 2.8 +/- 0.6 in normal subjects) and the slope of the end-systolic stress versus end-systolic volume index relation was decreased (2.7 +/- 1.3 in SCA versus 4.4 +/- 1.8 in normal subjects), suggesting LV dysfunction in those patients. Thus, LV muscle contractile performance is depressed in SCA. Increased preload and decreased afterload compensate for the LV dysfunction and maintain a normal ejection fraction and high cardiac output.

Systolic time intervals in chronic severe anaemia and effect of diuretic and digitalis

Systolic time intervals were measured from simultaneous high speed recordings of the electrocardiogram, phonocardiogram, and carotid artery pulse in 15 men with chronic severe anaemia not in heart failure and with a normal heart size, and in 15 normal men. Heart rates, electromechanical systole (QS2), pre-ejection period index (PEPI), left ventricular ejection time index (LVETI), and the ratio of pre-ejection period to left ventricular ejection time (PEP/LVET) did not differ significantly in the two groups. After the intravenous administration of frusemide in 10 of the anaemic patients, the pre-ejection period index was prolonged, the PEP/LVET ratio increased, heart rate increased, and the left ventricular ejection time index shortened. Intravenous digoxin did not alter the QS2 interval and heart rate significantly in the anaemic subjects. Left ventricular function in chronic severe anaemia as measured by systolic time intervals does not differ from that of normal controls. The effect of frusemide on the systolic time intervals is explained as an effect of the fall in preload, bringing cardiac function further down on the ascending limb of the Frank-Starling curve. Other related studies are discussed.

Normal left ventricular ejection fraction in systemic arteriovenous fistula. Implications for the use of noninvasive methods in differential diagnosis of heart failure

Heart failure is frequently a result of impaired systolic ventricular performance. We describe a patient with heart failure and a systemic arteriovenous fistula who had left ventricular enlargement and a normal left ventricular ejection fraction, demonstrated by gated cardiac blood pool scanning. The heart failure was relieved by surgical repair of the fistula, but the left ventricular ejection fraction did not change. These observations show that volume overload rather than impaired systolic function was the mechanism by which heart failure occurred in this patient with a systemic high output state and illustrate the value of gated cardiac blood scanning in noninvasively elucidating the mechanism of heart failure.

Postpartum cardiac failure--heart failure due to volume overload?

Ventricular function has been studied in 43 patients with the peripartum cardiac failure (PPCF) syndrome which occurs around Zaria. All patients had an echocardiogram on admission and 10 patients had right heart catheterization. Despite the gross edema, left ventricular function assessed by echocardiography and systolic time intervals was relatively good and the estimated cardiac output were high. At catheterization, although the pressures were high, the cardiac outputs were greater than normal in four out of six patients. No patient had a low cardiac output. These findings are not compatible with a severe heart muscle disorder, or cardiomyopathy. We suggest that the primary event in PPCF of Zaria is fluid retention which leads to a form of high output cardiac failure. The postpartum practices in this area (taking high sodium diets and lying on heated beds) almost certainly cause the fluid to accumulate initially, but the heart may be unable to meet the demands either because of preexisting heart muscle disease or, more likely, because of a rise of the peripheral resistance due to the volume expansion, overburdens such dilated hearts and leads to myocardial damage. Since there are similarities between this condition and PPCF in temperate climates, it is possible that there is a common mechanism which the traditional practices of this area have unveiled.

Role of circulatory congestion in the cardiorespiratory failure of obesity

The role of circulatory congestion in the cardiorespiratory dysfunction of massive obesity was investigated in 18 patients. They were hypervolemic and had increased cardiac outputs proportionate to their weight. The average resting left ventricular filling pressure was within the upper limits of normal, but it increased to abnormally high levels with increased venous return of passive leg raising, and further during exercise. The elevations in pressure were associated with high resting central blood volumes which increased significantly with exertion. These findings are consistent with reduced distensibility of the central circulation in these congested patients. Weight reduction was accompanied by a decrease in central blood volumes and restoration of a normal left ventricular response in three of four patients and a return toward normal in one. The improvement in ventricular function with relief of edema and dyspnea. In 14 patients with normal or only minimal alveolar hypoventilation, there were no significant transpulmonary diastolic pressure gradients despite a marked increase in left ventricular end-diastolic pressures. One patient, after regaining weight, subsequently had an abnormal gas exchange and an increased pulmonary vascular resistance. He and two others with severe alveolar hypoventilation demonstrated cor pulmonale on a background of left ventricular dysfunction and congestion of the circulation. Two other patients, the least obese of the group, had hypoventilation and cor pulmonale with normal left ventricular pressures. Hypervolemia and a hyperdynamic state are common features of the obese patients. High cardiac output is maintained despite marked circulatory congestion which may result in generalized anasarca and increased ventricular filling pressures. This clinical syndrome may be present in obese patients without intrinsic heart disease and may be reversible with weight reduction. The central circulatory congestion may contribute to the development of the alveolar hypoventilation syndrome in certain obese patients.

Circulatory changes in acute glomerulonephritis at rest and during exercise

In order to evaluate the effects of acute glomerulonephritis on the circulation, 6 patients were investigated at rest and during moderate exercise. With the patients in a state of rest the cardiac index and the stroke volume index were significantly higher in acute glomerulonephritis than normal, despite significantly raised right and left atrial pressures. Oxygen consumption was significantly increased (P less than 0.01) and the arteriovenous oxygen difference was narrowed significantly (P less than 0.001) in acute glomerulonephritis as compared to normal subjects. The calculated increase in cardiac output was due to both a rise in oxygen consumption and a narrowing of arteriovenous oxygen difference, the latter being more significant. The exercise-induced changes in cardiac output in the patients with glomerulonephritis were not different from those in normal subjects. These results showed that the circulatory changes in the oliguric stage of acute glomerulonephritis resemble those in the hyperkinetic states; the raised mean right atrial and pulmonary wedge pressures do not indicate the presence of heart failure when resting cardiac output is above normal level and response to exercise is normal.

Cardiac hemodynamics in alcoholic patients with chronic liver disease and a presystolic gallop

10 male subjects with chronic liver disease and with normal cardiovascular findings, except for the presence of a presystolic gallop, underwent right and left heart catheterization. In general, all of the patients had a high resting cardiac output, narrow arteriovenous oxygen difference, a low peripheral vascular resistance, and normal left ventricular end-diastolic pressures and volumes. The plasma volume was increased in the seven patients in which it was determined. On exercise, all of the patients demonstrated a significant increase in the left ventricular end-diastolic pressure and mean pulmonary artery pressure, while the stroke index remained the same or fell in seven of the subjects. It appears logical to assume that the excessive intake of alcohol is associated with an impairment in the metabolic and contractile properties of the left ventricle and the resultant hemodynamic effects may not be readily discerned in the resting state. However, upon exercise these patients, with a congested circulation, can show abnormal cardiac dynamics.