Cardiac Hypertrophy and Electrocardiography

Diagnosis and Characteristics

• Left ventricular hypertrophy (LVH) is often accompanied by secondary ST-T abnormalities, may show increased QRS duration, and P-wave abnormalities suggesting left atrial enlargement, according to the American College of Cardiology 1
• Cardiac hypertrophy, including right ventricular hypertrophy (RVH) and left ventricular hypertrophy (LVH), can be diagnosed using various criteria and guidelines provided by the American College of Cardiology and the American Heart Association 1
• The American College of Cardiology provides a systematic approach to axis determination using the following table to interpret lead I and lead aVF:

2

• Age-specific normal ranges for QRS axis are important to consider, including:

  Age Group	Normal QRS Axis Range
  Neonates	+30° to +190° [2, 3]
  Children 1-5 years	+10° to +110° [2]
  Children 5-8 years	up to +140° [2]
  Children 8-16 years	up to +120° [2]
  Adults	+30° to +90° [4]

• Right axis deviation (RAD) is a key component in diagnosing RVH, though the sensitivity of ECG criteria for RVH is generally low, and RAD has the greatest diagnostic accuracy in congenital heart disease, according to the American College of Cardiology 1
• RAD is commonly associated with conditions such as atrial septal defects, tetralogy of Fallot, pulmonary stenosis, and other conditions with right ventricular pressure or volume overload 1
• Left posterior fascicular block (LPFB) may be associated with RAD, characterized by an axis between 90° and 180° in adults, rS pattern in leads I and aVL, qR pattern in leads III and aVF, and QRS duration <120 ms, according to Circulation guidelines 5
• The American College of Cardiology recommends assessing for LPFB criteria and looking for RBBB patterns to rule out conduction disorders 5
• The American College of Cardiology recommends using the Sokolow-Lyon criteria (SV1 + RV5/6 > 35 mm) and the Cornell criteria (SV3 + RaVL > 28 mm for men or > 20 mm for women) for diagnosing left ventricular hypertrophy (LVH) 1
• Secondary ST-T abnormalities, including J-point depression, upwardly convex, downsloping ST segment depression, and asymmetrical T-wave inversion, may be present in LVH 1
• QRS duration is often increased in LVH, and left axis deviation may be present 1
• P-wave abnormalities suggesting left atrial enlargement, and slight QT interval prolongation may also be observed 1

Echocardiography and Risk Assessment

• Echocardiography is more sensitive than ECG for detecting LVH, and can measure left ventricular mass index, relative wall thickness, and diastolic function parameters, such as septal e' velocity, lateral e' velocity, and E/e' ratio, according to the European Society of Cardiology 6
• The European Society of Cardiology recommends measuring left ventricular mass index, with abnormal values being >95 g/m² in women and >115 g/m² in men, and assessing relative wall thickness, with abnormal values being >0.42 6
• The presence of ST-T abnormalities with LVH indicates higher cardiovascular risk 1
• Obesity can increase left ventricular mass but decrease QRS voltage, and gender differences in voltage criteria should be considered, with women having lower voltage thresholds 1

Management and Treatment

• For LAD associated with structural heart disease, treatment should focus on managing the underlying condition, such as hypertension, aortic stenosis, or other causes, as recommended by the American Heart Association 7
• For LAD with conduction system disease, monitoring for progression to higher-degree AV block and considering pacemaker implantation if symptomatic bradycardia or advanced AV block develops is crucial, according to the Heart Rhythm Society 7
• For pulmonary hypertension, the American College of Cardiology recommends pulmonary vasodilators and management of right heart failure 8
• Regular clinical assessment and serial echocardiography are necessary to monitor progression in patients with underlying structural heart disease, as stated by the European Society of Cardiology and the American College of Cardiology 7, 9
• Regular clinical assessment is necessary to monitor for symptoms of right heart failure, and to optimize management of underlying conditions such as chronic lung disease, as recommended by the American College of Cardiology 10, 1
• Immediate cardiac consultation is recommended for proper evaluation of ECG abnormalities, as advised by the American College of Cardiology and the Journal of the American College of Cardiology 11, 12