Histiocytoid cardiomyopathy

What it is

From: Orphanet

A rare arrhythmogenic disorder characterized by cardiomegaly, severe cardiac arrhythmias or sudden death, and the presence of histiocyte-like cells within the myocardium.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Tachycardia · Very frequent (99-80%)

A rapid heartrate that exceeds the range of the normal resting heartrate for age.

Supraventricular tachycardia · Frequent (79-30%)

Supraventricular tachycardia (SVT) is an abnormally increased heart rate (over 100 beats per minute at rest) with origin above the level of the ventricles.

Ventricular tachycardia · Frequent (79-30%)

A tachycardia originating in the ventricles characterized by rapid heart rate (over 100 beats per minute) and broad QRS complexes (over 120 ms).

Atrioventricular block · Occasional (29-5%)

Delayed or lack of conduction of atrial depolarizations through the atrioventricular node to the ventricles.

Cardiomegaly · Occasional (29-5%)

Increased size of the heart, clinically defined as an increased transverse diameter of the cardiac silhouette that is greater than or equal to 50% of the transverse diameter of the chest (increased cardiothoracic ratio) on a posterior-anterior projection of a chest radiograph or a computed tomography.

Congestive heart failure · Occasional (29-5%)

The presence of an abnormality of cardiac function that is responsible for the failure of the heart to pump blood at a rate that is commensurate with the needs of the tissues or a state in which abnormally elevated filling pressures are required for the heart to do so. Heart failure is frequently related to a defect in myocardial contraction.

Cough · Occasional (29-5%)

A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation.

Cyanosis · Occasional (29-5%)

Bluish discoloration of the skin and mucosa due to poor circulation or inadequate oxygenation of arterial or capillary blood.

Drowsiness · Occasional (29-5%)

Abnormal feeling of sleepiness or difficulty staying awake.

Exercise intolerance · Occasional (29-5%)

A functional motor deficit where individuals whose responses to the challenges of exercise fail to achieve levels considered normal for their age and gender.

Failure to thrive · Occasional (29-5%)

Failure to thrive (FTT) refers to a child whose physical growth is substantially below the norm.

Fever · Occasional (29-5%)

Body temperature elevated above the normal range.

Hepatomegaly · Occasional (29-5%)

Abnormally increased size of the liver.

Junctional ectopic tachycardia · Occasional (29-5%)

Junctional ectopic tachycardia (JET) is a unique type of supraventricular arrhythmia defined by narrow QRS complex and atrioventricular (AV) dissociation or retrograde atrial conduction in a 1:1 pattern.

Other findings in the same source

From: Orphanet

Additional reported features include Pallor (Occasional (29-5%)); Right bundle branch block (Occasional (29-5%)); Stroke-like episode (Occasional (29-5%)); Tachypnea (Occasional (29-5%)); Vomiting (Occasional (29-5%)); Wolff-Parkinson-White syndrome (Occasional (29-5%)); Agenesis of corpus callosum (Very rare (<4-1%)); Atrial fibrillation (Very rare (<4-1%)); Atrial flutter (Very rare (<4-1%)); Cleft palate (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Infancy; Neonatal

Inheritance in the source

From: Orphanet

Autosomal recessive; Unknown; X-linked dominant

Frequency and the population described

From: Orphanet

Point prevalence: <1 / 1 000 000; Worldwide; Class only. Reported case(s): 100.0; Worldwide. This is a published case count, not prevalence.

Which doctor should you see?

The suggested department for discussing Histiocytoid cardiomyopathy is Cardiology, with a cardiologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Is the main concern heart structure, rhythm, circulation or another cause?
• Which symptoms should change the timing of follow-up?
• How would a proposed investigation change the care plan?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Histiocytoid cardiomyopathy. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.