Introduction
Hypertrophic cardiomyopathy (HCM) is the most common inherited
cardiovascular
disease (1,2)
and is the most frequent cause of sudden cardiac death (SCD) in young
individuals, particularly athletes with a high level of
training (3–5).HCM
is a prevalent hereditary cardiovascular condition that affects one in
500 people in the general
population (6,7).
The cumulative proportion of sudden cardiac death (SCD) events in
childhood hypertrophic cardiomyopathy (HCM) within five years of
diagnosis ranged from 8% to
10% (8,9).
It is characterized by inadequate relaxation, hypercontractility,
reduced compliance, and left ventricle
hypertrophy (10–12).
HCM manifests as a chronic, progressive illness that can have a severe,
transformative effect on a person’s life and significantly lower quality
of life. Data on the cost to society associated with HCM has shown
significant increases in all-cause hospitalizations, hospital days,
outpatient visits, and total healthcare costs. The majority of cost
increases can be attributed to increased hospitalizations and hospital
days among symptomatic
patients (13).
The most often reported symptoms include syncope, palpitations,
exertional dyspnea, shortness of breath, ankle swelling, exhaustion,
sense of disorientation, and
lightheadedness (14,15).
Among the estimated 700,000 patients with HCM, only 100,000 have been
diagnosed in the United
States (16).
Underdiagnosis may be due in part to challenges in the diagnosis of
asymptomatic HCM patients, who typically receive a diagnosis by chance
or via systematic screening
efforts (12).
However, developments in the understanding of genetic and phenotypic
characteristics of HCM have promise for improving the identification of
the condition. Over the last twenty years, the condition has been linked
to abnormalities in genes that encode proteins of the cardiomyocyte’s
contractile
machinery (6,17,18).
It appears that significant progress has been made in understanding the
illness from both a genetic and clinical
standpoint (19).
Despite new developments, HCM remains underdiagnosed. Although the
population prevalence of HCM is between 1:200 and 1:500, only 10–20%
of cases are found by clinical
means (20).
Patients with HCM can have a normal life expectancy but a notable
percentage can develop HCM-related complications including heart
failure, atrial fibrillation (AF), and cardioembolic stroke, while a
smaller percentage have SCD or life-threatening ventricular
arrhythmias (21).
SCD is the most common cause of mortality among these patients and
frequently occurs during exercise. However, it often goes undetected
until death, as many individuals experience minimal or no significant
symptoms (6,11).
Consequently, a high index of diagnostic suspicion, accurate
identification, and a thorough clinical examination of patients and
family members are crucial for early identification and
treatment (20).
Identifying high-risk patients is crucial to lowering the risk of SCD in
young individuals with HCM, as effective treatment has the potential to
significantly reduce HCM mortality and
morbidity (22,23) This
can be achieved through exercise limitation, medication therapies, and
the use of implantable cardioverter defibrillators
(ICDs) (24) .
Therefore, there has been considerable interest in improving diagnostic
accuracy among HCM patients, especially young patients, to inform
intervention (21).
The HCM diagnosis is based on imaging techniques, such as
echocardiography or cardiovascular magnetic resonance (CMR), that reveal
increasing LV wall
thickness (21).
Thorough investigation has led to a better comprehension of risk
categorization for patients with HCM. The latest European Society of
Cardiology (ESC) guidelines propose evaluating clinical examination,
family history, 48-hour electrocardiography (ECG), echocardiography, and
exercise testing for this
purpose (6,11).
The European Society of Cardiology (ESC) has proposed specific cardiac
screening guidelines for young competitive
athletes (25),
which include assessing symptoms and family medical history (e.g.,
premature death, HCM), conducting a physical examination, and performing
a resting 12-lead ECG. A recent Danish study revealed that a large
proportion of individuals who experienced SCD due to HCM had previous
symptoms, and most of them had sought medical attention before their
death, in contrast to the control
group (26).
These findings suggest there is an opportunity to improve the
identification of HCM among at-risk patients, as many patients seek
treatment.
The ECG continues to be a fundamental aspect of evaluating patients with
HCM. Moreover, it is experiencing a ”renaissance” in the realm of
cardiomyopathies, not only due to its cost-effectiveness and widespread
accessibility, but also because it offers information pertinent to
morphology, function, and genetic foundation
simultaneously (21) HCM
has diagnosis so far relied on identification of left ventricular
hypertrophy (LVH) with a wall thickness greater than 15 mm using
echocardiography or CMR. However, this degree of LVH is not exclusive to
HCM and may stem from various other pathological conditions, widening
the differential. In such instances, the ECG is highly valuable in
assisting with the differentiation between sarcomeric HCM and its
phenocopies (21).
There is a growing body of literature evaluating the accuracy of ECG
markers in predicting HCM, however, there remains a need for research on
the extent to which ECG findings are predictive of HCM identified on
echocardiography. Therefore, the aim of this study was to evaluate the
prevalence of abnormal ECG findings, including LVH, T wave inversion,
left bundle branch block (LBBB), and left atrial enlargement in
participants with suspected HCM detected during screening
echocardiography.