Congestive heart failure ventricular filling

Heart failure is a clinical syndrome characterized by a history of specific signs and symptoms related to congestion and hypoperfusion. As HF can occur in the presence or absence of fluid overload, the term heart failure is preferred over the former term congestive heart failure. Heart failure results from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood.1 Many disorders such as those of the pericardium, epicardium, endocardium, or great vessels may lead to HF, but most patients develop symptoms due to impairment in left ventricular (LV) myocardial function. 

Congestive heart failure (CHF) is a clinical syndrome with multiple causes and involve the right or left ventricle or both and in CHF, cardiac output is usually below the normal range. This ventricular dysfunction may be systolic, which leads to inadequate force generation to eject blood normally and diastolic, which leads to inadequate relaxation to permit normal filling. Systolic dysfunction, with decreased cardiac output and significantly reduced ejection fraction is typical of acute heart failure, especially that resulting from myocardial infarction. 

Relation of left ventricular (LV) performance to filling pressure in patients with acute myocardial infarction, an important cause of heart failure. The upper line indicates the range for normal, healthy individuals. If acute heart failure occurs, function is shifted down and to the right. Similar depression is observed in patients with chronic heart failure. (Modified and reproduced with permission, from Swan HJC, Parmley WW Congestive heart failure. In Sodeman WA Jr, Sodeman TM [editors]. Pathologic Physiology. Saunders, 1979.)... 

In addition to their diuretic activity, loop agents appear to have direct effects on blood flow through several vascular beds. Furosemide increases renal blood flow. Furosemide and ethacrynic acid have also been shown to reduce pulmonary congestion and left ventricular filling pressures in heart failure before a measurable increase in urinary output occurs, and in anephric patients. 

Possible uses. Arteriolar vasodilators are given to lower blood pressure in hypertension (p.314), to reduce cardiac work in angina pectoris (p.318), and to reduce ventricular afterload (pressure load) in cardiac failure (p.322). Venous vasodilators are used to reduce venous filling pressure (preload) in angina pectoris (p. 318) or congestive heart failure (p.322). Practical uses are indicated for each drug group. 

Horses with congestive heart failure (CHF) and AF have a poor prognosis for conversion to sinus rhythm (Reef et al 1988). Digitalization is the treatment of choice for horses with AF secondary to CHF to reduce the ventricular response rate and, therefore, to optimize ventricular filling. Propranolol may also be used to reduce the... 

THERAPEUTIC USES A major use of loop diuretics is in the treatment of acute pulmonary edema. A rapid increase in venous capacitance in conjunction with a brisk natriuresis reduces left ventricular filling pressures and thereby rapidly relieves pulmonary edema. Loop diuretics also are used widely for the treatment of chronic congestive heart failure when diminution of extracellular fiuid volume is desirable to minimize venous and pulmonary congestion see Chapter 33). In this regard, a meta-analysis of randomized clinical trials demonstrates that diuretics cause a significant reduction in mortality and the risk of worsening heart failure, as well as an improvement in exercise capacity. 

Cora Nari. Cora Nari was in left ventricular heart failure (LVF) when j she presented to the hospital with her second heart attack in 8 months. The diagnosis of LVF was based, in part, on her rapid heart rate (104 beats/min) and respiratory rate. On examining her lungs, her physician heard respiratory rales, caused by inspired air bubbling in fluid that had filled her lung air spaces secondary to LVF. This condition is referred to as congestive heart failure. 

Figure 13-2. Ventricular function (Frank-Starling) curves. The abscissa can be any measure of preload—fiber length, filling pressure, pulmonary capillary wedge pressure, etc. The ordinate is a measure of useful external cardiac work—stroke volume, cardiac output, etc. In congestive heart failure, output is reduced at all fiber lengths and the heart expands because ejection fraction is decreased. As a result, the heart moves from point A to point B. Compensatory sympathetic discharge or effective treatment allows the heart to eject more blood, and the heart moves to point C on the middle curve.

Ohno M, Cheng CP, and Little WC. Mechanism of altered patterns of left ventricular filling during the development of congestive heart failure. Circulation 1994 89 2241-50. 

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