Heart failure INDEX

Invasive hemodynamic monitoring should be considered in patients who are refractory to initial therapy, whose volume status is unclear, or who have clinically significant hypotension such as systolic BP <80 mm Hg. Such monitoring helps guide treatment and classify patients into four specific hemodynamic subsets based on cardiac index and pulmonary artery occlusion pressure (PAOP). Refer to textbook Chap. 16 (Heart Failure) for more information. 

The obvious symptom of starvation is a loss of weight, which is most easily assessed by a decrease in the body mass index (BMI). Indeed, it is an excellent predictor of death from starvation. A value of BMI below about 13 in men and about 12 in women is not compatible with life. These values coincide with a loss of about 50% of lean body mass. The major causes of death from malnutrition in developed countries are pneumonia, other infections or heart failure. 

Theophylline is a narrow therapeutic index drug with significant difference in bioavailability following oral administration. The half-life of the drug is increased by heart failure, cirrhosis and viral infections, in elderly patients, and by certain drugs, such as cimetidine, ciprofloxacin, oral contraceptives and fluvoxamine. The half-life is decreased in smokers, chronic alcoholism, and by certain drugs, such as phenytoin, rifampicin and carbamazepine. 

Theophylline has a narrow therapeutic index and produces side effects that can be severe, even life threatening. Importantly, the plasma concentration of theophylline cannot be predicted reliably from the dose. In one study, the oral dosage of theophylline required to produce therapeutic plasma levels (i.e., between 10 and 20 pg/mL) varied between 400 and 3,200 mg/day. Heterogeneity among individuals in the rate at which they metabolize theophylline appears to be the principal factor responsible for the variability in plasma levels. Such conditions as heart failure, liver disease, and severe respiratory obstruction will slow the metabolism of theophylline. 

Measurements of arterial pressure, cardiac output, stroke work index, and pulmonary capillary wedge pressure are particularly useful in patients with acute myocardial infarction and acute heart failure. Such patients can be usefully characterized on the basis of three hemodynamic measurements arterial pressure, left ventricular filling pressure, and cardiac index. One such classification and therapies that have proved most effective are set forth in Table 13-4. When filling pressure is greater than 15 mm Hg and stroke work index is less than 20 g-m/m2, the mortality rate is high. Intermediate levels of these two variables imply a much better prognosis. 

Coenzyme QIO is a powerful antioxidant naturally occurring in the mitochondria of myocardium, and it is an electron carrier in the mitochondrial synthesis of ATP. Patients with heart failure have lower myocardial levels of coenzyme QIO, but supplementation has been demonstrated to have variable benefits in randomized controlled trials. One meta-analysis on the use in congestive heart failure showed improvements in stroke volume, ejection fraction, cardiac output, cardiac index, and end diastolic volume index. " Another antioxidant associated with beneficial effects in cardiac patients is lycopene, a natural constituent of tomatoes. Lycopene is the major carotenoid found in human serum, and epidemiological studies have indicated an effect of dietary supplementation in reducing heart disease. Few dietary interventions have been reported one study showed a mild but significant hypocholesterolemic effect, and another showed a significant reduction in LDL oxidation. " Animal studies show an antiatherogenic effect of DHEA, and a review of the clinical trials and studies on DHEA in males with coronary heart disease reported a favorable or neutral effect. Plasma levels of DHEA are decreased in patients with chronic heart failure in proportion to its severity. ... 

On the premise that phosphodiesterase inhibitors also inhibit the production of cytokines, milrinone has been used in the treatment of nine patients with the systemic inflammatory response sjmdrome and compared with seven patients with congestive heart failure (4). In both groups mikinone significantly altered cardiac index, pulmonary capillary wedge pressure, and left ventricular stroke work index. In the patients with cardiac failure it also reduced systemic vascular resistance index, and the dose of adrenaline had to be increased substantially during milrinone infusion to counteract vasodilatation. 

In a retrospective view of 63 patients who received intravenous milrinone for more than 24 hours for advanced cardiac failure, the mean dose was 0.43 micro-gram/kg/minute and the mean duration of therapy 12 (range 1-70) days (14). After 24 hours of therapy there was significant improvement in pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac index. Because of the nature of the study, which was not placebo-controlled, it is impossible to be sure what events could have been attributed to the milrinone. However, the authors reported five cases of asymptomatic, non-sustained ventricular tachycardia, six of symptomatic ventricular tachycardia, and three deaths, one in ventricular tachycardia and two in heart failure. There was no difference in the incidence of these adverse events in patients who received milrinone for more than 7 days compared with the others. 

A 16-year-old boy who took long-term verapamil after a Mustard operation for transposition of the great arteries developed severe congestive heart failure, which did not respond to diuretics. Systemic vascular resistance was increased by 75% and pulmonary vascular resistance by 150% the cardiac index was reduced from 3.0 to 1.8 1/minute/m. Ejection fraction and atrial pressure were unchanged and neurohormonal causes were excluded. The heart failure resolved after withdrawal of verapamil. 

Fig. 11. The hemodynamic response to exercise is influenced by the p2-Ilel64 polymorphism in patients with heart failure. Exercise-induced changes were significantly lower in patients with Ilel64 for 02, stroke volume (SV), cardiac index (Cl), and systemic vascular resistance (SVR). All changes represent increases by the indicated percentage, except for SVR, which was a decrease. HR, heart rate. / < 0.05 vs Thrl64. V02 is maximal oxygen consumption. (Reprinted with permission from ref. 34.)...

Mundy BJ, McCord J, Nowak RM. B-type natriuretic peptide levels are inversely related to body mass index in patients with heart failure. J Am Coll Cardiol 2003 41 suppl A 158A,... 

FIGURE 14-9. Hemodynamic subsets of heart failure based on cardiac index and pulmonary artery occlusion pressure. (Adapted with permission from N Engl j Med 1976 295 1356-1362.)... 

Patients with a cardiac index of less than 2.2 L/m per minute and a PAOP higher than 18 mm Hg are in hemodynamic subset TV. These patients have the worst prognosis of any subset and illustrate the typical hemodynamic profile for the patient hospitalized for severe heart failure. 

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