What is acute left ventricular (LV) dysfunction?

From the Guidelines

Acute left ventricular (LV) dysfunction is a life-threatening condition characterized by a sudden impairment in the heart's ability to pump blood effectively, often manifested by a weak pulse, poor peripheral perfusion, and pulmonary congestion, as described in the ACC/AHA guidelines for the management of patients with acute myocardial infarction 1.

Clinical Presentation

The clinical presentation of acute LV dysfunction includes symptoms such as a weak pulse, poor peripheral perfusion with cool and cyanotic limbs, obtundation, and oliguria, with a third heart sound potentially audible, as outlined in the study 1. Blood pressure is usually low, and there are variable degrees of pulmonary congestion.

Diagnosis and Management

Diagnosis and management of LV dysfunction are determined by the specific hemodynamic derangements present, including pulmonary capillary wedge pressure, cardiac output, and systemic arterial pressure 1. Treatment often involves modest diuresis using intravenous furosemide, in combination with afterload and preload reduction using nitroglycerin, which is initiated at 5 µg/min and increased gradually until mean systolic arterial pressure falls by 10% to 15% but not below 90 mm Hg 1.

Key Considerations

• The institution of ACE inhibitor therapy is also appropriate in this setting, as it helps to reduce the workload on the heart and improve cardiac function.
• In cases of severe LV dysfunction with markedly low systolic arterial pressure, intravenous norepinephrine may be administered to increase blood pressure, followed by a potential switch to dopamine, and eventually dobutamine to reduce the dopamine infusion and improve cardiac contractility 1.
• Continuous monitoring of vital signs, urine output, and cardiac function is crucial during treatment to ensure the best possible outcomes and adjust therapy as needed.

From the Research

Definition and Causes of Acute LV Dysfunction

• Acute left ventricular (LV) dysfunction is common in the critical care setting and more frequently affects the elderly and patients with comorbidities 2.
• It can be caused by various factors, including acute coronary syndrome, stress (takotsubo) cardiomyopathy, and the cardio-depressant effect of inflammatory mediators and endotoxins in septic shock 2.
• Other causes of global LV dysfunction include tachycardia, hypertension, and severe metabolic abnormalities, which can independently cause global LV dysfunction 2.

Diagnosis and Treatment of Acute LV Dysfunction

• Early diagnosis is important to direct treatment of complications of stress cardiomyopathy, such as dynamic LV outflow tract obstruction, heart failure, and arrhythmias 2.
• Routine troponin testing may help early detection of cardiac injury and biomarkers could have prognostic value independent of prior cardiac disease 2.
• Echocardiography is ideally suited to quantify LV dysfunction and determine its most likely cause 2.
• Treatment options for acute LV dysfunction include interventions directed toward alleviating acute myocardial ischemia, assessing and treating acute left ventricular dysfunction, and preventing or treating arrhythmias and conduction disturbances 3.
• Pharmacological agents, such as diuretics, nitroglycerin, and dobutamine, may be used to treat acute LV dysfunction, and support devices, coronary angioplasty, and cardiac surgery may be necessary in some cases 3.

Effects of Nitroglycerin on Acute LV Dysfunction

• Nitroglycerin has been shown to improve left ventricular function and decrease the extent of myocardial ischemia in patients with acute myocardial infarction 4.
• Nitroglycerin infusion can reduce left ventricular filling pressure and improve diastolic filling in acute dilated heart failure 5.
• The use of nitroglycerin may be beneficial in patients with acute LV dysfunction, especially those with ischemic etiology 6.

Prognosis and Management of Asymptomatic Left Ventricular Dysfunction

• Patients with asymptomatic left ventricular dysfunction (ALVD) are at high risk for developing symptomatic heart failure, and few management strategies have been shown to slow disease state progression or improve long-term morbidity and mortality 6.
• Angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) have been shown to improve clinical outcomes among patients with ALVD 6.
• Beta blockers, statins, and automatic implantable cardioverter defibrillators (ICDs) may also be beneficial in certain patients with ALVD 6.