What are the cardiac complications of dengue fever?

Cardiac Complications of Dengue Fever

Dengue fever causes cardiac involvement in 12-50% of hospitalized patients, with the most frequent manifestations being arrhythmias, myocarditis, pericarditis, and left ventricular systolic dysfunction—complications that are significantly underdiagnosed and associated with adverse outcomes. 1

Spectrum of Cardiac Manifestations

Structural and Functional Abnormalities

The cardiac complications occur through multiple mechanisms including direct viral invasion, immune-mediated damage, and inflammatory responses 1:

• Myocarditis (2.9-5.7% of cases): Can mimic myocardial infarction clinically and may progress to fulminant myocarditis with significant morbidity 2
• Left ventricular systolic dysfunction (5.7%): More common in male patients 1, 2
• Pericardial involvement:
  • Pericardial effusion (1.3-26% depending on detection method) 3, 2
  • Pericarditis (0.1%) 2
  • Cardiac tamponade (0.1%)—rare but life-threatening 2, 4

Electrical Abnormalities

ECG changes occur in approximately 30.6% of patients with cardiac involvement 2:

• Sinus bradycardia (8.8%)—most common rhythm disturbance 2
• ST-T wave abnormalities (8.6%): Nonspecific ST-T changes, ST depression (7.9%), T-wave inversions (2.3%), particularly in leads V1-V4 5, 2
• Various arrhythmias: Can range from benign to life-threatening 1

Acute Coronary Syndromes

In rare cases, the inflammatory response triggers intracoronary thrombosis leading to acute myocardial infarction, coronary dissection, and intramural hematoma 1. This represents a critical but uncommon complication requiring immediate recognition.

Biochemical Evidence

• Elevated cardiac troponin I (38% in one study): Indicates myocardial injury 3
• Elevated CK-MB (37.5%): Reflects cardiac enzyme release 5
• Elevated BNP/NT-proBNP: Suggests myocardial strain 3

High-Risk Patient Identification

A recent 2026 cross-sectional study of 919 patients identified specific predictors for cardiac involvement 3:

Independent Risk Factors (in order of strength):

1. Elevated D-dimer (aOR 5.90)—strongest predictor
2. Hypoalbuminemia (aOR 3.06)
3. Age >60 years (aOR 3.05)
4. WHO warning signs (aOR 2.77)
5. Elevated serum creatinine (aOR 2.20)
6. Anemia (aOR 1.84)
7. Thrombocytopenia (aOR 1.82)

Population-Specific Risks

• Pediatric patients: Some reports suggest higher incidence of cardiac complications 1
• Male patients: Face higher risk of LV systolic dysfunction compared to women 1

Critical Clinical Pitfalls

Massive Underdiagnosis Problem

Only a small percentage of dengue patients receive cardiac evaluation, especially in endemic areas, leading to significant underdiagnosis 1. This is particularly problematic because:

• Cardiac manifestations present atypically 5
• Non-specific symptoms overlap with dengue's systemic features 1
• Healthcare focus predominantly targets neurologic or hemorrhagic complications 1
• Limited access to imaging in resource-limited settings 1

Prognostic Significance

The presence of ANY abnormality on echocardiography has been associated with adverse outcomes in dengue patients 1. This underscores the importance of cardiac screening in high-risk patients.

Diagnostic Approach

When to Suspect Cardiac Involvement

Evaluate for cardiac complications in patients with:

• Any of the high-risk factors listed above
• Clinical features: chest pain, dyspnea, syncope, hemodynamic instability 3
• ECG abnormalities on routine screening 6

Recommended Evaluation Strategy

Based on the 2025 European Heart Journal guidelines 1:

1. Echocardiography: Most accessible tool and should be performed in patients with ECG abnormalities or hemodynamic instability 6

   • Detects LV dysfunction, pericardial effusion, wall motion abnormalities
   • Serial assessments may be needed for monitoring

2. ECG monitoring: Essential for detecting arrhythmias and ischemic changes

   • Consider Holter monitoring for persistent symptoms 1

3. Cardiac biomarkers: Troponin I and BNP/NT-proBNP help identify myocardial injury 3

4. Advanced imaging (when available and patient stable):

   • Cardiac MRI for detailed myocardial characterization 1
   • Coronary CT to exclude obstructive disease when acute coronary syndrome suspected 1

Management Principles

Treatment is largely supportive 6, focusing on:

• Hemodynamic support: Inotropes for cardiogenic shock 4
• Fluid management: Careful balance given plasma leakage risk
• Arrhythmia management: Standard protocols apply
• Pericardiocentesis: For cardiac tamponade 4
• Close monitoring: ICU care for severe cardiac involvement

Pathophysiologic Mechanisms

Understanding helps guide supportive care 6:

• Direct viral myocardial invasion
• Immune-mediated inflammation
• Electrolyte imbalances
• Lactic acidosis
• Ischemia from hypotension
• Derangement of intracellular calcium handling

Long-Term Considerations

Emerging evidence suggests cardiovascular effects may extend beyond the acute phase 7, including:

• Subclinical myocardial dysfunction
• Endothelial dysfunction
• Potential for dilated cardiomyopathy
• Thromboembolic complications

However, most cardiac manifestations are transient 6, though they require recognition and management to prevent acute morbidity and mortality.