What are the symptoms of arrhythmias following a cardiac contusion?

Symptoms of Arrhythmias Following Cardiac Contusion

Arrhythmias following cardiac contusion present with palpitations, syncope or near-syncope, chest pain, dizziness, and in severe cases, sudden cardiac arrest or cardiogenic shock. 1, 2, 3, 4

Primary Arrhythmic Symptoms

The key manifestations of post-contusion arrhythmias include:

• Palpitations are a cardinal symptom, reflecting the underlying rhythm disturbance from myocardial injury 1, 3
• Syncope (complete loss of consciousness) occurs with hemodynamically significant arrhythmias, particularly high-degree atrioventricular block and ventricular tachyarrhythmias 2, 3
• Near-syncope or presyncope (dizziness without complete loss of consciousness) indicates transient arrhythmic episodes causing brief drops in cardiac output 3
• Chest pain or angina pectoris may accompany arrhythmic episodes, reflecting myocardial ischemia from the contusion itself or arrhythmia-induced demand 3

Severe Presentations

Life-threatening manifestations include:

• Cardiogenic shock can develop from severe arrhythmias combined with myocardial dysfunction, presenting with hypotension, altered mental status, and signs of end-organ hypoperfusion 4
• Sudden cardiac arrest represents the most catastrophic presentation, with fatal ventricular arrhythmias occurring even days after the initial trauma 2
• Hemodynamic instability manifests as persistent hypotension (systolic blood pressure <90 mm Hg) despite fluid resuscitation 5

Critical Timing Considerations

A crucial pitfall is assuming safety based on initial presentation—fatal arrhythmias can develop 4-6 days after trauma despite a normal admission ECG and absence of early arrhythmias. 2 This delayed presentation occurs because:

• Myocardial contusion evolves over days with progressive interstitial edema, hemorrhage, necrosis, and inflammatory infiltration creating an arrhythmogenic substrate 2
• Both supraventricular tachycardias and high-degree AV block can emerge as late complications requiring weeks of treatment 3
• The presence of multiple other injuries increases the risk of delayed fatal arrhythmias 2

Associated Symptoms from Underlying Injury

Beyond the arrhythmia itself, patients may experience:

• Dyspnea or shortness of breath from concurrent heart failure, pulmonary contusion, or hemothorax 5
• Anxiety or sense of impending doom accompanying tachyarrhythmias 6
• Symptoms may be masked or attributed to other injuries in polytrauma patients 2

Diagnostic Approach

When arrhythmic symptoms are present:

• 12-lead ECG is mandatory to identify rhythm disturbances, conduction abnormalities, or signs of ischemia 5, 3
• Cardiac troponin I or T are highly sensitive for myocardial injury and stratify risk for complications 1
• Continuous ECG monitoring is essential, as a normal initial ECG does not exclude subsequent life-threatening arrhythmias 2, 3
• Echocardiography (transthoracic or transesophageal) detects wall motion abnormalities, valve injuries, pericardial effusion, and ventricular dysfunction 5
• Extended monitoring beyond 24 hours is required in high-risk patients, particularly those with multiple injuries, abnormal ECG, or elevated troponins 2, 3

Risk Stratification

Patients at highest risk for symptomatic arrhythmias include those with:

• Sternal fractures combined with ECG changes or elevated troponins 5
• Hemopericardium or cardiac chamber rupture 5
• Rising cardiac biomarkers or persistent ECG abnormalities 5, 1
• Multiple associated injuries beyond the chest trauma 2

The severity of arrhythmic symptoms does not necessarily correlate with the extent of structural damage or overall prognosis, making objective monitoring essential rather than relying on symptom severity alone. 6