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Case Media

Pearls – Chronic Chagas Cardiomyopathy with Recurrent Ventricular Tachyarrhythmia

1. Always consider Chagas cardiomyopathy when you have a patient from Latin America who presents with non-ischemic cardiomyopathy.
2. Chagas cardiomyopathy is associated with an unfavorable prognosis and serves as an independent predictor of mortality.
3. Chagas cardiomyopathy is arrhythmogenic and requires consideration for ICD and, when appropriate, catheter based ventricular tachycardia ablation.
4. It is crucial to treat patients with nifurtimox and benznidazole when appropriate.
5. Provide screening for first-degree family members or close relatives who may have lived in the same environment.

Show Notes – Chronic Chagas Cardiomyopathy with Recurrent Ventricular Tachyarrhythmia

What is the disease progression in Chagas disease⁵?

• Acute Stage:
  • Initial infection occurs through contact with infected triatomine bug feces or contaminated blood products.
  • Symptoms may be mild or absent but can include fever, fatigue, body aches, and swelling at the injection site (chagoma).
  • Parasitemia is high during this stage.
• Intermediate/Indeterminate Stage:
  • The infection becomes chronic if left untreated.
  • Many individuals enter this stage with no noticeable symptoms.
  • Parasitemia levels decrease, but the parasite remains in the body, mainly in muscle and cardiac tissue.
  • This stage can last for years to decades.
• Chronic Stage:
  • Some individuals will remain asymptomatic throughout their lives.
  • Cardiac complications (chronic Chagas cardiomyopathy) can lead to arrhythmias, congestive heart failure, and sudden death.
  • Digestive complications can result in enlarged esophagus (megaesophagus) and colon (megacolon), leading to difficulties in swallowing and digestion.

When do we suspect, and who do we screen, for Chagas disease?

• The seroprevalence of CCM in the USA is as high as 19%^16. Among patients with LVEF<50%, the rate of positive serology was 28%. Similarly, the seropositivity among patients who reported recognizing the reduviid bug was 31%.
• Individuals who have lived in endemic countries of Mexico, Central and South America, excluding the Caribbean islands.
• T. cruzi seroprevalence is highest in Bolivia, Argentina, Paraguay, Ecuador, El Salvador, and Guatemala⁶.
• Close relatives and those born to women from endemic countries⁷.
• Persons with a history of bite/exposure to the vector responsible for transmission.
• EKG abnormalities suggestive of infection even in the absence of symptoms.
• TTE changes: regional wall motion abnormalities (particularly basal inferolateral, apical aneurysm)⁴

What diagnostic tests can confirm the diagnosis of chronic Chagas cardiomyopathy?

• Serologic testing: no available assay has sufficient sensitivity and specificity to be used alone. Two serologic tests based on different antigens and/or techniques (e.g., ELISA and IFA) are used in parallel to increase the accuracy of the diagnosis⁸.
• EKG: RBBB, LAFB, AV block, atrial fibrillation, ventricular tachycardias
• TTE: dilated cardiomyopathy, reduced ejection fracture, regional wall motion abnormalities, left ventricular apical aneurysm
• Cardiac MRI: myocardial fibrosis is a striking feature of CCM and LGE is used to detect and qualify the extent. Myocardial fibrosis also plays a role in risk stratification of CCM⁹.

What are the indications for treatment of Chagas disease?

• Acute phase.
• Early chronic phase, including women of childbearing age.
• Reactivated infection (e.g., after immunosuppression).
• Adults <50 years of age who do not have advanced cardiomyopathy (stage B1)¹⁰.
• In all other cases, the potential benefit of medication in delaying the development of Chagas disease should be weighed against potential adverse reactions- benznidazole and nifurtimox should not be taken by pregnant women or people with kidney or liver failure.

What are the benefits of screening and early diagnosis? 

• Effective treatment, particularly in the acute phase.
• The BENEFIT trial showed that Trypanocidal therapy with benznidazole in patients with CCM did not significantly reduce cardiac deterioration^11.
• Screening of family members/friends who grew up in the same environment.
• Reduction of transmission due to blood transfusions and congenital transmission.
• Early initiation of GDMT (guideline-directed medical therapy) for clinical heart failure 2/2 CCM.
• Ongoing surveillance for cardiomyopathy can prevent catastrophic events (heart blocks, ventricular arrhythmias, thromboembolic events).
• Cost effectiveness: Early diagnosis and treatment may reduce healthcare costs compared to the treatment of complications that arise from the chronic phase of the disease. Early diagnosis may also reduce the number of endomyocardial biopsies.

How is the management of VT unique in chronic Chagas cardiomyopathy?

• In comparison to cardiomyopathies of other etiologies, CCM is associated with a higher risk of life-threatening ventricular arrhythmias and an unfavorable prognosis^12,14.
• Per ESC guidelines, the greatest benefit of ICD in CCM is in patients with an LVEF ≤40%¹⁵.
• Per Gali et al, most patients with an ICD received appropriate ICD shocks/therapies regardless of their LV systolic function¹³.
• Ablation of VT requires extensive mapping because multiple discrete circuits are typically present. The most common site of origin is the LV basal inferolateral wall. However, 1/3^rd of the foci is located on the epicardial surface. This necessitates epicardial mapping to achieve successful ablation⁶.