7 Other Cardiac Emergencies

Recognize acute cardiac emergencies

Acute heart failure, cardiogenic shock, and care after return of spontaneous circulation are time-critical emergencies. Rapid recognition, stabilization, and treatment of the underlying cause can limit further injury. Activate emergency and specialist support early, and follow current local protocols.

Acute heart failure

Acute decompensated heart failure occurs when the heart cannot meet the body’s needs, often causing pulmonary or systemic congestion. Suspect it with worsening breathlessness, orthopnea, hypoxemia, crackles, jugular venous distention, or peripheral edema. Severe pulmonary edema may appear abruptly with marked respiratory distress and frothy sputum.

Assess airway, breathing, circulation, mental status, oxygen saturation, blood pressure, and perfusion. Sit the patient upright if tolerated; begin continuous ECG and vital-sign monitoring, and obtain IV access. Give supplemental oxygen for hypoxemia. Consider noninvasive positive-pressure ventilation for significant respiratory distress if the patient can protect their airway and has no contraindication; prepare for advanced airway support if respiratory failure worsens.

Obtain a 12-lead ECG and assess for possible triggers, including acute coronary syndrome, arrhythmia, infection, pulmonary embolism, or medication nonadherence. Investigations may include chest imaging, blood tests, and bedside ultrasound or echocardiography.

For clinical congestion, IV loop diuretics are commonly used. IV nitroglycerin or another vasodilator may be considered for dyspnea when blood pressure is adequate; avoid vasodilators in hypotension. Reassess symptoms, blood pressure, oxygenation, urine output, and perfusion frequently.

Cardiogenic shock

Cardiogenic shock is inadequate tissue perfusion caused by cardiac pump failure. Acute myocardial infarction is a common cause, but severe heart failure, mechanical complications, myocarditis, and dangerous arrhythmias can also cause it. Hypotension is important, but shock may be developing before profound hypotension appears.

Look for altered mentation, cool or clammy skin, weak pulses, delayed capillary refill, low urine output, rising lactate, or worsening renal function. These signs may occur alongside chest pain, pulmonary congestion, or a new arrhythmia.

Treat suspected shock as an emergency. Activate a shock response or critical-care or cardiology team, establish monitoring and IV access, obtain an ECG and urgent diagnostic assessment, and identify the cause. Use fluids cautiously: large empiric boluses can worsen pulmonary edema, while a carefully selected fluid challenge may be appropriate when low preload is suspected.

Vasoactive medicines and temporary mechanical circulatory support require expert, closely monitored selection; mechanical support is not routine for every patient. When acute coronary occlusion is suspected, urgent revascularization assessment is essential.

Care after cardiac arrest

ROSC is the start of ongoing resuscitation, not the end of care. Stabilize airway and circulation while looking for the cause of the arrest and complications of resuscitation.

Oxygenation and ventilation

Initially use $100\%$ inspired oxygen until oxygenation can be measured reliably. Then titrate oxygen to avoid both hypoxemia and hyperoxemia. The AHA target is $\mathrm{SpO_2}$ of $90\text{–}98\%$, or $\mathrm{PaO_2}$ of $60\text{–}105\ \mathrm{mm\ Hg}$. In comatose adults, generally target $\mathrm{PaCO_2}$ of $35\text{–}45\ \mathrm{mm\ Hg}$.

Perfusion and cause

Avoid hypotension and maintain mean arterial pressure (MAP) of at least $65\ \mathrm{mm\ Hg}$, adjusting care to the patient’s condition. Obtain a 12-lead ECG as soon as feasible and consider ultrasound or CT to identify causes and complications. Persistent ST-segment elevation calls for emergency coronary angiography. Angiography may also be appropriate without ST elevation when shock, recurrent ventricular arrhythmias, or ongoing severe ischemia is present. No single vasopressor is established as best for every post-arrest patient.

Neurologic and temperature care

For adults who do not follow verbal commands after ROSC, use a deliberate protocol for temperature control within $32\text{–}37.5\ ^\circ\mathrm{C}$ and maintain control for at least $36$ hours. Evaluate for seizures; EEG can help assess patients who remain unresponsive. Avoid hypoglycemia and marked hyperglycemia.

Do not make early neurologic prognoses from a single finding. Use a multimodal assessment after considering confounding effects such as sedation, generally at least $72$ hours after normothermia.

Connect recognition with treatment

Recognize acute heart failure through respiratory distress and congestion; support breathing, treat congestion when appropriate, and search for the trigger. Suspect cardiogenic shock when signs of poor perfusion appear, even if hypotension is not yet profound; escalate early and treat the cause. After ROSC, continue resuscitation with careful oxygenation, ventilation, and blood-pressure management, prompt evaluation for reversible causes, and protocolized neurologic and temperature care.