Ventricular Tachycardia as the Initial Symptom of Cardiac Hydatidosis

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Ventricular Tachycardia as the Initial Symptom of Cardiac Hydatidosis

Introduction

Cardiac hydatidosis, a rare manifestation of Echinococcus infection, typically occurs secondary to hepatic or pulmonary involvement. This case report details a 44-year-old female presenting with ventricular tachycardia (VT) as the primary manifestation of cardiac hydatidosis, highlighting the diagnostic challenges and multidisciplinary management required for this condition. The patient’s history of surgically treated hepatic hydatidosis 30 years prior and her residence in a pastoral region provided critical clues for connecting recurrent arrhythmias to parasitic cardiac involvement.

Clinical Presentation

The patient reported two months of recurrent palpitations accompanied by cold sweats, transient vision loss (amaurosis), vomiting, and limb weakness. During symptomatic episodes, electrocardiogram (ECG) confirmed monomorphic ventricular tachycardia with a rate consistent with VT (specific rate not quantified in the original report). Initial management with intravenous amiodarone (dose unspecified) provided symptomatic relief, prompting discharge. Subsequent referral for ablation evaluation led to transfer to a tertiary center.

Diagnostic Workup

Initial Assessments

  • 24-hour Holter monitoring revealed frequent premature ventricular contractions (PVCs), corroborating arrhythmia burden.
  • Transthoracic echocardiography identified hypokinesis at the ventricular septal apex and an apical thrombus (Figure 1B). Left ventricular ejection fraction was not quantified, but regional wall motion abnormalities suggested structural pathology.
  • Coronary computed tomography angiography (CTA) ruled out coronary artery disease, showing normal luminal patency.

Advanced Imaging

  • Myocardial perfusion imaging revealed paradoxical apical wall motion, a left ventricular apical aneurysm, and evidence of myocardial infarction in the anterior, anterolateral, posterolateral, and septal walls. These findings initially raised suspicion for ischemic cardiomyopathy, but the absence of coronary disease contradicted this hypothesis.
  • Cardiac magnetic resonance imaging (MRI) provided definitive characterization:
    • Myocardial thinning at the septal apex.
    • A 6.17 cm × 4.67 cm cystic mass at the left ventricular posterior apex with peripheral calcification (“eggshell” appearance) and no contrast enhancement (Figure 1C).
    • Adhesion between the cyst’s outer membrane and pericardium.

Confirmation of Etiology

The patient’s history of hepatic hydatidosis and imaging findings aligned with cardiac cystic echinococcosis. Abdominal CT confirmed residual degenerative hepatic hydatid cysts, supporting systemic parasitic involvement.

Pathophysiology and Mechanism of Arrhythmia

Cardiac hydatid cysts typically embed in the myocardium, with the left ventricle (60–65%) and interventricular septum (15–20%) being common sites. In this case, cyst invasion into the septal apex created a proarrhythmic substrate through multiple mechanisms:

  1. Mechanical distortion: Cyst-induced myocardial stretching alters electrophysiological properties, enhancing automaticity or triggering re-entry.
  2. Inflammatory response: Peri-cystic fibrosis and scarring disrupt normal conduction pathways.
  3. Microvascular compression: Local ischemia from cyst expansion may exacerbate arrhythmogenicity.

The absence of coronary disease and the localization of hypokinesis to cyst-affected regions confirmed the parasitic etiology of VT.

Surgical Management and Outcomes

Preoperative Planning

Given the cyst’s size (6.17 cm × 4.67 cm), calcification, and myocardial adherence, thoracotomy was prioritized over percutaneous ablation or antiparasitic therapy. Surgical goals included:

  • Complete cyst excision to eliminate arrhythmogenic foci.
  • Prevention of cyst rupture, which risks anaphylaxis or disseminated infection.
  • Preservation of ventricular integrity.

Operative Findings

Intraoperative exploration revealed:

  • A thick-walled cystic mass adherent to the pericardium and infiltrating the apical myocardium (Figure 1D).
  • Degenerative changes with calcified outer layers, consistent with chronic infection.

The cyst was enucleated intact, and partial pericardiectomy was performed to ensure complete resection.

Postoperative Course

  • No VT episodes were detected on continuous monitoring.
  • Four months post-cardiac surgery, residual hepatic cysts were excised.
  • At 16-month follow-up, the patient remained free of ventricular arrhythmias, confirming successful elimination of the arrhythmic substrate.

Discussion

Diagnostic Challenges

This case underscores four key diagnostic pitfalls in cardiac hydatidosis:

  1. Mimicking thrombus: Echocardiographic misinterpretation of hydatid cysts as thrombi may delay specific therapy.
  2. Ischemia-like perfusion defects: Myocardial perfusion imaging findings can falsely suggest infarction, necessitating correlation with coronary anatomy.
  3. Latent presentation: Decades may separate initial hepatic infection and cardiac symptoms, complicating etiology determination.
  4. Arrhythmia as the sole manifestation: Unlike typical hydatidosis symptoms (e.g., dyspnea, chest pain), VT dominated this presentation, requiring high clinical suspicion.

Imaging Modalities Compared

  • Echocardiography: First-line for detecting intracardiac masses but limited in tissue characterization (e.g., thrombus vs. cyst).
  • Cardiac MRI: Superior for delineating cyst architecture, myocardial infiltration, and pericystic inflammation. Late gadolinium enhancement helps differentiate viable myocardium.
  • CT: Critical for detecting calcifications (“eggshell” sign) and evaluating extracardiac involvement.

Surgical vs. Medical Therapy

Albendazole, the mainstay of medical therapy for hydatidosis, has limited cardiac penetration and risks cyst rupture during treatment. Surgery remains definitive for:

  • Symptomatic cysts (e.g., arrhythmogenic foci).
  • Large (>5 cm) or calcified lesions.
  • Pericardial involvement with adhesion risk.

Conclusion

This case illustrates ventricular tachycardia as a rare but critical presentation of cardiac hydatidosis, necessitating integration of clinical history, multimodality imaging, and surgical expertise. Early MRI and CT are pivotal for differentiating parasitic cysts from thrombi or tumors. Radical excision remains curative for arrhythmia secondary to myocardial hydatidosis, with favorable long-term outcomes achievable through staged management of multiorgan involvement.

DOI: https://doi.org/10.1097/CM9.0000000000000520

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