What is the clinical significance of sinus rhythm with mild left axis deviation, mild intraventricular conduction delay, fragmented QRS, and non-ischemic Late Gadolinium Enhancement on Cardiac Magnetic Resonance Imaging with normal Echocardiogram findings?

From the Guidelines

The patient's clinical presentation of sinus rhythm with mild left axis deviation, mild intraventricular conduction delay, fragmented QRS, and non-ischemic Late Gadolinium Enhancement on Cardiac Magnetic Resonance Imaging with normal Echocardiogram findings suggests an underlying cardiac condition, likely early cardiomyopathy, which warrants close monitoring and further investigation. The presence of non-ischemic Late Gadolinium Enhancement is a significant finding, as it indicates myocardial fibrosis or scarring, which can be associated with various cardiomyopathies, including inflammatory or infiltrative conditions 1. The normal echocardiogram findings suggest that the overall heart function is preserved, but the abnormal electrical patterns and myocardial scarring pattern may indicate a potential risk for future cardiac events.

The clinical significance of these findings can be understood by considering the potential underlying conditions that may cause such a presentation. For example, cardiac sarcoidosis, myocarditis sequelae, or other cardiomyopathies can present with preserved ejection fraction but abnormal electrical patterns 1. The non-ischemic scarring pattern may also suggest a condition such as cardiac fibrosis or scarring due to inflammation rather than coronary disease.

In terms of management, close cardiac monitoring is recommended, with follow-up echocardiograms every 6-12 months, consideration of Holter monitoring to detect any arrhythmias, and possibly cardiac electrophysiology consultation. Further investigation may be necessary to rule out conditions like cardiac sarcoidosis, myocarditis sequelae, or other cardiomyopathies that can present with preserved ejection fraction but abnormal electrical patterns. The use of cardiac MRI with Late Gadolinium Enhancement can help identify myocardial fibrosis or scarring, which can inform the diagnosis and management of the underlying condition 1.

Some key points to consider in the management of this patient include:

• The importance of close cardiac monitoring to detect any changes in cardiac function or electrical patterns
• The potential need for further investigation to rule out underlying conditions such as cardiac sarcoidosis or myocarditis sequelae
• The use of cardiac MRI with Late Gadolinium Enhancement to identify myocardial fibrosis or scarring
• The consideration of Holter monitoring to detect any arrhythmias
• The potential need for cardiac electrophysiology consultation to manage any abnormal electrical patterns.

From the Research

Clinical Significance of Sinus Rhythm with Mild Left Axis Deviation, Mild Intraventricular Conduction Delay, Fragmented QRS, and Non-Ischemic Late Gadolinium Enhancement

• The presence of non-ischemic late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is associated with an increased risk of ventricular arrhythmias and sudden cardiac death 2, 3.
• However, the relationship between LGE and surface conduction abnormalities is not well established, with some studies suggesting that LGE is not associated with conduction abnormality 4.
• Fragmented QRS (fQRS) on electrocardiogram (ECG) is a marker of myocardial scar and fibrosis, and is associated with an increased risk of ventricular arrhythmias and sudden cardiac death 5, 6.
• Mild left axis deviation and mild intraventricular conduction delay on ECG may be indicative of underlying cardiac disease, but their clinical significance in the context of non-ischemic LGE and fQRS is unclear.
• The presence of normal echocardiogram findings does not necessarily rule out the presence of underlying cardiac disease, as LGE on CMR can detect myocardial fibrosis and scar that may not be visible on echocardiogram 2, 3.

Risk Stratification and Prognosis

• Patients with non-ischemic cardiomyopathy and LGE on CMR are at increased risk of ventricular arrhythmias and sudden cardiac death, and may benefit from implantable cardioverter-defibrillator (ICD) therapy 2, 3.
• The presence of fQRS on ECG may be a useful marker for identifying patients at high risk of ventricular arrhythmias and sudden cardiac death 5, 6.
• The clinical significance of mild left axis deviation and mild intraventricular conduction delay on ECG in the context of non-ischemic LGE and fQRS requires further study, but may be indicative of underlying cardiac disease that warrants further evaluation and monitoring.