Task force IV: pharmacologic interventions. Emergency cardiac care

Heart Failure Complicating Acute Mtyocardial Infarction

Factors predisposing the older person with acute myocardial infarction (MI) to develop heart failure (HF) include an increased prevalence of MI, multivessel coronary artery disease, decreased left ventricular (LV) contractile reserve, impairment of LV diastolic relaxation, increased hypertension, LV hypertrophy, diabetes mellitus, valvular heart disease, and renal insufficiency. HF associated with acute MI should be treated with a loop diuretic. The use of nitrates, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, aldosterone antagonists, beta-blockers, digoxin, and positive inotropic drugs; treatment of arrhythmias and mechanical complications; and indications for use of implantable cardioverter-defibrillators and cardiac resynchronization is discussed.

Heart Failure–Complicating Acute Myocardial Infarction

This article addresses issues related to acute myocardial infarction (MI) complicated by heart failure, particularly in elderly patients. Findings have shown that acute MI complicated by congestive heart failure (CHF) is associated with a high mortality, and that women with acute MI are more likely to be older and to develop CHF than men with acute MI. In general, management of CHF complicating acute MI is similar in older and younger patients. Actions discussed include hemodynamic monitoring; the administration of oxygen; and the use of morphine, diuretics, nitroglycerin, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, spironolactone, beta-blockers, calcium channel blockers, magnesium, digoxin, and positive inotropic drugs. The article also discusses measures for treating arrhythmias and for diagnosing mechanical complications.

Heart-Failure–Complicating Acute Myocardial Infarction

This article addresses issues related to acute myocardial infarction(MI) complicated by heart failure, particularly in elderly patients. Findings have shown that acute MI complicated by congestive heart failure (CHF) is associated with a high mortality, and that women with acute MI are more likely to be older and to develop CHF than men with acute MI. In general, management of CHF-complicating acute MI is similar in older and younger patients. Actions discussed include hemodynamic monitoring; the administration of oxygen; and the use of morphine, diuretics, nitroglycerin,angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, spironolactone, beta-blockers, calcium channel blockers, magnesium, digoxin, and positive inotropic drugs. The article also discusses measures for treating arrhythmias and for diagnosing mechanical complications.

Heart failure complicating acute myocardial infarction

Older people with congestive heart failure associated with acute myocardial infarction should be treated with loop diuretic therapy. Class I indications for the use of early intravenous beta blockade in patients with acute myocardial infarction are patients without a contraindication to beta blockers who can be treated within 12 hours of onset of myocardial infarction; patients with continuing or recurrent ischemic pain; and patients with tachyarrythmias, such as atrial fibrillation with a rapid ventricular rate. Class I indications for the use of angiotensin-converting enzyme inhibitors during acute myocardial infarction are (1) patients within the first 24 hours of onset of a suspected acute myocardial infarction with ST segment elevation in two or more anterior precordial leads or with clinical heart failure in the absence of significant hypotension or contraindications to the use of angiotensin-converting enzyme inhibitors, (2) patients with myocardial infarction and a left ventricular ejection fraction of less then 40%, (3) and patients with clinical heart failure on the basis of systolic pump dysfunction during and after convalescence from acute myocardial infarction. No class I indications exist for using calcium channel blockers or magnesium during acute myocardial infarction.

Use of nitroglycerin for the treatment of acute myocardial infarction

After a decade of warnings against the use of nitrates in acute myocardial infarction (MI), they are becoming recognized for their potential to salvage left ventricular (LV) myocardium, geometry and function. Low-dose intravenous (IV) nitroglycerin (NTG) infusion for the first 48 h after acute MI, titrated to lower mean blood pressure by 10% to 30%, but not below 80 mmHg, has been shown to be safe, to improve hemodynamics, and to decrease infarct size, infarct expansion, complications, and deaths in a prospective, randomized, single-blind study of 310 patients. In addition, low-dose NTG infusion for the first 48 h, followed by prolonged buccal NTG given during healing after acute MI in an eccentric dose schedule to minimize tolerance, was found to limit further progressive remodeling and preserve LV function. Meta-analysis of nitrate studies in acute MI indicate that they improve survival. Preliminary and ongoing studies suggest that prolonged NTG therapy post MI can produce further benefit.

Pharmacological management of acute myocardial infarction

The routine medical management of patients with acute myocardial infarction (AMI) has undergone major changes in the last decade. Several large-scale trials have firmly established the effectiveness of thrombolytic therapy, beta blockers, and aspirin in the treatment of AMI. The critical issues include reducing myocardial oxygen demand and restoring adequate blood supply to the ischemic regions of the myocardium. As a result, the ability to intervene in patients with AMI has improved significantly. The purpose of this review is to discuss briefly the results of major trials of primary and secondary pharmacological intervention which had a direct impact on the care of patients with AMI. It concludes with current recommendations for the management of patients with AMI.

Pathogenesis and management of acute heart failure and cardiogenic shock: role of inotropic therapy

Patients with acute heart failure or cardiogenic shock following myocardial infarction have a high mortality. The first priority is to salvage any remaining viable myocardium, either by thrombolytic agents or, if necessary, by coronary angioplasty. A mechanical cause for the heart failure or shock needs to be excluded. Thereafter, the optimal therapeutic regimen needs to be chosen on the basis of each patient's hemodynamic profile. Patients can be broadly classified into three groups: (1) patients with a high left ventricular filling pressure (> 18 mm Hg) and a cardiac index < 2.2 L/min/m2 but systolic arterial pressure > 100 mm Hg; (2) patients with a systolic arterial pressure < 90 mm Hg, left ventricular filling pressure > 18 mm Hg, and cardiac index < 2.2 L/min/m2; and (3) patients with an elevated right ventricular filling pressure (> 10 mm Hg) and cardiac index < 2.2 L/min/m2 and a systolic arterial pressure < 100 mm Hg. Patients in the first subset usually require the use of vasodilator therapy and/or dobutamine. The choice of inotropic agent in patients in the second hemodynamic subset depends on the degree of systemic hypotension; dopamine is usually preferred initially because it increases arterial pressure in addition to improving cardiac output. Once the systemic blood pressure has been stabilized, dobutamine can be substituted for superior augmentation of cardiac output and its additional beneficial effects on the left ventricular filling pressure. Norepinephrine may be indicated in cases of severe systemic hypotension. Patients in hemodynamic subset 3, ie, right ventricular infarction, are treated with volume expansion and dobutamine. Use of nonpharmacologic means of circulatory support, eg, intra-aortic balloon pump or left ventricular assist device may also be required in any of these subsets.

Management of acute myocardial infarction

This article presents plans of therapy based on current knowledge of pathophysiologic mechanisms, taking into consideration the rapid changes in availability of new drugs (or new experiences with old drugs) and new therapeutic interventions. Persistence of ischemic pain in the acute phase, or its recurrence during early convalescence, is a signal of a high-risk state for additional coronary events, and aggressive measures are required to prevent them. The indications, and the role of invasive hemodynamic monitoring in the treatment of left ventricular failure and/or hypotension, are discussed.

Cardiogenic and hypovolemic shock

The symptoms, signs, and pathophysiology of two major forms of shock are discussed. Newer modalities of pharmacologic and supportive therapy for stabilization and reversal of these states are presented, including the use of the intra-aortic balloon pump and early surgical therapy for cardiogenic shock.

Compatibility of intravenous drugs in a coronary intensive care unit

In a coronary intensive care unit (CCU) it is often necessary to utilize extensive pharmacologic interventions and multiple intravenous medications in order to stabilize a critically ill patient. However, the necessity of several intravenous infusions often presents the problem of compatibility of these medications when infused within a common line. The pharmacist must possess adequate skill to identify potential incompatibilities by retrieving information on the physical and chemical compatibilities of various intravenous medications. In a critical care setting, time is an important factor, and information that can be obtained rapidly and reliably is vital for the pharmacist to prevent the administration of an irritating substance or a medication that has undergone deterioration as a result of chemical inactivation. A compatibility table containing the most commonly used drugs in a CCU has been developed based on currently available literature, including standard reference texts, about these medications. The table outlines the potential for interactions, within a single intravenous line, when several drugs are infused concurrently. In addition, a review of the concepts of physical and chemical incompatibility is presented. The stability of an admixture is defined utilizing requirements established in the USP NF monographs and manufacturers' specifications. The resulting table concisely organizes vital information in a form that allows rapid, accessible information to the pharmacist in a critical care setting, where it is most needed.

Sustained improvement of pulmonary hemodynamics in patients at rest and during exercise after thrombolytic treatment of massive pulmonary embolism

This study assessed the long-term effects of thrombolytic treatment in patients with acute massive pulmonary embolism (PE). Seven patients with PE that followed deep-vein thrombosis underwent pulmonary angiography and pressure measurements before and 6 +/- 3 days (mean +/- SD) and 15 +/- 4 months after treatment with intrapulmonary infusions of urokinase (average dose 1724 U/kg X hr) and heparin (average dose 17 U/kg X hr). Treatment was guided by daily measurements of pulmonary arterial (PA) pressure and was continued until PA pressure had normalized (average of 6 days). Late after treatment patients returned for pulmonary angiographic examination, right heart catheterization at rest and during bicycle exercise, and phlebography of the deep veins of both legs. Pulmonary angiograms showed massive obstruction before therapy (Walsh index 15 +/- 2 points of a maximum of 18 points), which was improved 6 days (3 +/- 3 points) and 15 months (1 +/- 2 points) after therapy. Mean PA pressure declined from 37 +/- 9 to 13 +/- 3 mm Hg after 6 days and to 15 +/- 3 mm Hg after 15 months. No recurrence of PE was observed. In six of seven patients at rest and during bicycle exercise (up to 100 W) in the supine position mean PA pressure and total pulmonary resistance remained within normal limits. Over the short term all patients showed clinical signs of deep-vein thrombosis; 15 months later four patients had normal deep veins, but three patients had still phlebographic signs of old thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)