Ischemia induces aggravation of baseline repolarization abnormalities in left ventricular hypertrophy: a deleterious...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Imaging

Background:

• Left ventricular hypertrophy (LVH) and hypertension (HT) are known risk factors for cardiovascular events, including sudden cardiac death (SCD), in patients with coronary artery disease (CAD).
• Experimental studies suggest myocardial hypertrophy alters electrophysiological properties, potentially increasing SCD vulnerability, but human data is lacking.
• Altered repolarization, particularly prolonged repolarization, is implicated in increased SCD risk.

Purpose of the Study:

• To investigate human data supporting a repolarization-related mechanism for increased SCD risk in CAD patients with LVH and/or HT.
• To assess ventricular repolarization parameters at rest and during ischemia in different patient groups.

Main Methods:

• Three-dimensional vectorcardiographic monitoring was performed on 187 CAD patients during coronary angioplasty.
• Eight parameters reflecting ventricular repolarization were analyzed at rest and during maximum ischemia.
• Patients were categorized into three groups: LVH (with or without HT), HT without LVH, and neither.

Main Results:

• Patients with LVH exhibited the most abnormal baseline repolarization and a significantly more pronounced repolarization response during ischemia.
• Hypertension (HT) patients showed intermediate repolarization parameter values between LVH and control groups.
• Repolarization abnormalities were exacerbated during ischemia, particularly in patients with LVH.

Conclusions:

• The study provides human data aligning with animal and epidemiological findings on repolarization disturbances and SCD risk.
• LVH and HT significantly impact ventricular repolarization during ischemia in CAD patients.
• Disturbed repolarization is a likely contributor to increased SCD risk in this population, though other factors may also play a role.