Page 595 - Cardiac Nursing

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C HAP TE R 24 / Heart Failure and Cardiogenic Shock 571

prove some exercise parameters. Calcium-channel blockers have
Table 24-9 ■ DIASTOLIC DYSFUNCTION GENERAL important lusitropic effects that enhance ventricular relaxation,
TREATMENT with verapamil usually the drug of choice, particularly in hyper-
trophic cardiomyopathy. -Adrenergic blockers also improve
Goal Treatment
LV relaxation by decreasing myocardial oxygen consumption
Reduce venous pressure Decrease central blood volume and ischemia.
Salt restriction Atrial fibrillation with rapid ventricular response is poorly toler-
Diuretics ated, and electrical or chemical cardioversion should be performed
Venodilation
ACE inhibitors to restore normal sinus rhythm. -Blockers and/or amiodarone
Angiotensin II receptor blockers may be required to control and prevent atrial fibrillation. Ra-
Nitrates diofrequency ablation and atrioventricular pacing may also be
Morphine used. Agents with positive inotropic actions are not indicated if
Maintain atrial contraction, Electrical or pharmacologic systolic function is normal; these agents appear to provide little
synchrony cardioversion
Sequential AV pacing benefit and have the potential to worsen pathophysiologic
Biventricular pacing processes, such as myocardial ischemia.
Prevent tachycardia Digitalis in atrial fibrillation
-adrenergic blockers Specific Strategies
Calcium-channel blockers (verapamil,
diltiazem) Anticoagulation. Patients with increased LV volumes and re-
Treat and prevent ischemia Nitrates, -adrenergic blockers, duced function are at increased risk for LV thrombus formation.
calcium-channel blockers
Coronary revascularization Embolization of these thrombi into the systemic circulation can re-
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(percutaneous coronary intervention sult in transient ischemic attacks and cerebrovascular accidents.
or bypass surgery) Several studies have attempted to determine whether chronic anti-
Control hypertension and ACE inhibitors, other antihypertensive coagulation reduces this transient ischemic attack/cerebrovascular
promote regression of agents accident risk, but their results are mixed. 62,63 Therefore, routine
hypertrophy Surgical intervention (e.g., aortic valve
repair) anticoagulation with warfarin is recommended only for patients
Attenuate neurohormonal ACE inhibitors, -adrenergic blockers with atrial fibrillation, a previous history of systemic pulmonary
1
activation embolism, or mobile ventricular thrombi. Use of warfarin for pa-
Prevent fibrosis and promote ACE inhibitor or angiotensin II receptor tients with LVEF of 0.35 or less may be considered, but careful as-
regression of fibrosis blockers
Spironolactone sessment of the risks and benefits should be undertaken.
Anti-anginal agents Device Therapy. Device therapy extends to biventricular
Improve ventricular relaxation -adrenergic blocker
Calcium-channel blockers (in pacing and ICDs. Cardiac resynchronization therapy by simulta-
hypertropic cardiomyopathy) neous pacing of the LV and RV through biventricular pacing may
Systolic unloading agents be an advantageous therapy that, in patients with severe HF and
intraventricular conduction delay, improves ventricular coordina-
Adapted from Gaasch, W. H., & Shick, E. C. (2000). Heart failure with normal left tion and hemodynamics. 64 By synchronizing LV contraction,
ventricular ejection fraction: A manifestation of diastolic dysfunction. In M. H. there is improvement of LV dP/dP T, EF, and cardiac output, as wellT
T
P
Crawford & J. P. DiMarco (Eds.), Cardiology (Section 5, pp 6.1–6.8). London: 65
Mosby. as reduction of wall stress and LV filling pressures.
ICDs are the treatment of choice in patients with LV dysfunc-
tion who have documented ventricular tachycardia or ventricular
diastolic dysfunction has similarities and dissimilarities to the fibrillation. 1,66 Because HF patients are at high risk for SCD,
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treatment of HF caused by systolic dysfunction. The first step is these patients should be evaluated for ICD indication criteria:
the treatment of the underlying cause. Ischemia is relieved LVEF less than 0.35, previous MI, and/or nonsustained ventricu-
through standard medical management and revascularization for lar tachycardia. 66 Combined device therapy includes ICD with
CAD. Medical management extends to the use of nitrates, - pacemaker capabilities (Chapter 28).
adrenergic blockers, and calcium-channel blockers. Volume re- Surgical Therapy. Cardiac transplantation is an established
duction with diuretics is used to control pulmonary congestion long-term surgical treatment for HF. However, the scarcity of
1
and peripheral edema; diuretics should be titrated carefully. Con- available organs and strict eligibility criteria make this an option
trol of systemic hypertension is important, with ACE-I assisting for only approximately 2000 people in the United States each
in normalizing blood pressure and reducing LV mass in patients year. 67 Mitral regurgitation occurs to some extent in the remod-
with hypertension-induced LVH. Other antihypertensive agents eled, dilated ventricle, and mitral valve reconstruction has been
also may be needed. undertaken. LVADs are emerging as destination therapy in some
Tachycardia is poorly tolerated, and atrial tachyarrhythmias patients with end-stage HF. Mechanical support of the failing my-
and even sinus tachycardia have a negative impact on diastolic ocardium is currently an area of widening investigation and ap-
function. Allowing maximum time for diastolic filling and low- plication (Chapter 26).
ering diastolic filling pressure can be accomplished by rate-slow-
ing agents. Benefits of a slower rate include increased coronary Inhibitors of the RAAS
perfusion time, decreased myocardial oxygen requirements, and
increased myocardial efficiency. -Adrenergic blockers and cal- Angiotensin-Converting Enzyme Inhibitors. The use of
cium-channel blockers (amlodipine or diltiazem) have been used ACE-I has been conclusively shown to improve long-term prog-
to prevent excessive tachycardia and also have been shown to im- nosis in HF. 68–70 ACE-I block the formation of AT, which