Electrocardiographic abnormalities associated with malignant hyperthermia susceptibility

Area of Science:

• Anesthesiology
• Cardiology
• Genetics

Background:

• Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle.
• Susceptibility can be diagnosed via muscle biopsy but often remains undetected in individuals without prior hyperpyrexic crises.
• Electrocardiography (ECG) is a non-invasive tool for cardiac assessment.

Purpose of the Study:

• To investigate the prevalence of electrocardiographic (ECG) abnormalities in patients susceptible to malignant hyperthermia (MH) but without a history of MH crises.
• To determine if ECG findings can serve as a potential indicator of MH susceptibility.

Main Methods:

• Serial ECGs were reviewed in 93 patients diagnosed with MH susceptibility through caffeine contracture and ATP depletion tests.
• Patients had no documented history of pyrexic crises.
• ECG findings were analyzed for abnormalities, including conduction defects, repolarization changes, and increased voltages.

Main Results:

• Abnormal ECGs were identified in 26 out of 93 (28%) MH-susceptible patients.
• Common abnormalities included conduction defects (14 patients), repolarization abnormalities or Q waves (9 patients), and increased voltages suggesting left ventricular hypertrophy (3 patients).
• These abnormalities were observed in the absence of hypertension.

Conclusions:

• A significant proportion of individuals susceptible to malignant hyperthermia exhibit abnormal ECG findings, even without a history of MH crises.
• Electrocardiographic abnormalities may represent a subclinical manifestation of MH susceptibility.
• ECG screening could potentially aid in identifying individuals at risk for malignant hyperthermia.