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C HAP TE R 24 / Heart Failure and Cardiogenic Shock 577

often prior to the development of overt symptoms. Two small stud-
ies have shown that while most patients with HF recall being asked Table 24-12 ■ RELATIVE AND ABSOLUTE
to monitor their weights at home, and describe this behavior as CONTRAINDICATIONS TO EXERCISE TRAINING AMONG
“important,” only approximately 30% reported engaging in the PATIENTS WITH STABLE CHRONIC HEART FAILURE
behavior. 154, 173 Daily weights were among the five least frequently Relative Contraindications Absolute Contraindications
performed self-care behaviors. 152
Most patients with HF are instructed to weigh themselves 4 lb wt gain over previous 1 to Progressive dyspnea at rest over
one time per day. Although the ideal time of this weight has not 3 days previous 5 days
been studied, it is most likely not as important as the fact that it Continuous or intermittent dobutamine Ischemia at low levels of exercise
is performed at a consistent time each day. Patients are typically T In systolic BP with exercise Uncontrolled diabetes
NYHA IV
Acute systemic illness or fever
asked to weigh upon rising in the morning, after urinating and Complex ventricular arrhythmia at rest Recent embolism
prior to dressing or eating. The accuracy or precision of the home Complex ventricular arrhythmia Thrombophlebitis
device (scale) used for weighing has likewise not been studied. with exercise Active pericarditis or myocarditis
However, the accuracy of the measurement probably is not as im- Supine resting HR 100 beats/min Severe aortic stenosis
Myocardial infarction within
portant as its reproducibility. Recognizing mild volume overload previous 3 weeks
early on increases the efficacy of treatment interventions, such as New onset atrial fibrillation with
augmentation of diuretic dose and heightened sodium restriction. rapid ventricular response
These interventions can interrupt the cycle of progressive myocar-
dial that results in reduced renal perfusion and consequent sodium Wt, weight; BP, blood pressure; NYHA, New York Heart Association functional class;
HR, heart rate.
and water retention, manifested clinically as shortness of breath, Adapted from Working Group on Cardiac Rehabilitation & Exercise Physiology and
paroxysmal nocturnal dyspnea, and lower extremity edema. Working Group on Health Failure of the European Society of Cardiology. (2001).
European Heart Journal, 22, 125–135.
l
l
Activity and Exercise. A classic symptom associated with HF
is exercise intolerance, characterized by fatigue or shortness of
breath. Exploring the pathophysiologic mechanisms underlying
these symptoms has been the focus of much study over the last
decade. 174 Figure 24-13 depicts the mechanisms for augmenting cardiac output in the patient with and without HF. The mecha-
nisms involve both myocardial and peripheral abnormalities, in-
cluding altered cardiac output in response to exercise, abnormal
redistribution of blood flow, reduced mitochondrial volume den-
A
(2-4 ) HR sity, impaired vasodilatory capacity, heightened sympathetic vas-
(4-6 ) C.O. cular resistance, and impaired sympathetic tone. 175–177
(20-50%) SV (at least 100 mL) Until recently, patients with HF have been instructed to avoid
exercise. In the late 1990s there was mounting evidence from small
controlled studies that neurohormonal activation, symptoms, rest-

Frank starling mechanism of EDV and ESV
ing cardiac function, and quality of life appeared to improve with
exercise. 174 Larger well-controlled trials now demonstrate a clear
morbidity, mortality, and the quality of life benefit of low- and
contractility peripheral vasodilation moderate-level exercise training. 178–181 While stable patients ben-
efit from exercise training, Table 24-12 highlights a subset of pa-
tients for whom exercise prescriptions should be altered.
B Lower max HR
50% of normals C.O. (low workload) Diet. Patients with HF frequently lack a clear understanding
of the dietary recommendations. While there is a lack of clinical
SV (limited to
50-65 mL) trials evaluating the effect of many of the dietary recommenda-
tions made to patients with HF, the general consensus is that lim-
iting sodium intake lessens the risk of volume overload. While
Minimal preload reserve to EDV and/or

most clinicians agree that limiting sodium intake is important,

Inability to ESV
incorporation of this strategy into the lives of patients is more
complex. Lack of knowledge, reduced food selection, cost, and in-
systemic vascular resistance
terference with socialization have been identified as factors associ-
contractility -adrenergic responsiveness 182
ated with patient nonadherence to a low-sodium diet. How-
ever, the findings of a recent study suggests that if patients
sympathetic and renin-angiotensin systems
Arterial
vasodilation perceive the positive link between low or consistent sodium intake
response to (i.e., avoiding episodic high sodium items) and reduced risk of
exercise
hospitalization for volume overload (i.e., HF), they are more
likely to adhere to a reduced sodium diet. 183 Thus, Bennett et al.
■ Figure 24-13 Mechanisms to augment cardiac output (from
Pina, I. L., Apstein, C. S., Balady, G. J., et al. [2003]. Exercise and validated the common sense association that if patients understand
heart failure: A statement from the American Heart Association Com- the rationale behind the treatment recommendations, adherence is
mittee on exercise, rehabilitation, and prevention. Circulation, 107[8], more likely improved. Fluid restriction has not been shown to be
1210–1225.) A series indicates cardiac output augmentation in a nor- effective in either short- or long-term volume management 184 in
mal heart. B series indicates cardiac output augmentation in HF. this population.