Imaging
Evaluation of Diastolic Dysfunction Using Cardiac Magnetic Resonance Imaging
Tarun Pandey and Kedar Jambhekar
Department of Radiology, University of Arkansas for Medical Sciences
Abstract
Left ventricular (LV) diastolic dysfunction and diastolic heart failure (DHF) account for approximately 40–50% of all patients with congestive heart failure (CHF). Diastolic dysfunction can be evaluated directly by invasive cardiac catheterisation techniques or non-invasively by transthoracic echocardiography (TTE) or cardiac magnetic resonance (CMR) imaging. Due to its high spatial and temporal resolution, CMR is the accepted gold standard for evaluating ventricular systolic function. Using the cine-phase contrast technique, CMR can interrogate inflow through the mitral valve and pulmonary veins towards evaluation of diastolic dysfunction and has shown good correlation with TTE. Additionally, CMR can evaluate direct myocardial diastolic parameters that have no echo correlate, such as diastolic torsion rate. As CMR has the ability to characterise a range of diastolic impairments, it will likely become an important diagnostic test in the future, capable of comprehensive LV function evaluation. In this article, we focus on LV diastology, and review CMR methodology and parameters for the diagnosis of diastolic dysfunction.
Keywords
Diastolic function, cardiovascular magnetic resonance, left ventricle, congestive heart failure, magnetic resonance imaging
drtarunpandey@gmail.com
Diastolic dysfunction and diastolic heart failure (DHF) have shown a steady increase in prevalence over the course of the last decade.1
DHF is now regarded as a major public health
concern. It shows an increasing trend with age and exceeds the incidence rate of systolic heart failure by the eighth decade of life.2
Recent data show that the
In fact, it is estimated that approximately 25–30% of individuals 45 years of age in the general community have asymptomatic diastolic dysfunction.3
prevalence of DHF has increased from 38 to 54% of all heart failure (HF) cases.4,5
Unlike systolic HF, DHF has an unfavourable survival rate that has remained unchanged over the years.5
New-onset symptomatic DHF is a
lethal disease with a five-year mortality rate of approximately 50%.6 Predisposing conditions for DHF are older age, female gender, diabetes and obesity, arterial hypertension and left ventricular (LV) hypertrophy.7,8
Terminology
Clinically, there is a distinction between diastolic dysfunction and DHF. While DHF refers to the clinical syndrome of HF in the setting of a normal ejection fraction (EF), diastolic dysfunction refers to an abnormality of diastolic function regardless of the clinical status of the patient.9
It should, however, be noted that DHF is not exclusive
to patients with normal EF (see ‘Diagnostic Criteria’ section). Both systolic and diastolic HF can co-exist in patients with DHF. Hence, in the recent literature the term HF with normal EF (HFNEF) has been used.10
DHF and HFNEF will be used interchangeably in the rest of the article.
© T O UCH BRIEFINGS 2010
Diagnostic Methods
Invasive Methods
DHF can be diagnosed invasively by measuring: an elevated LV end diastolic pressure (>16mmHg); an elevated mean pulmonary capillary wedge pressure (>12mmHg); or an increased time constant of LV relaxation ‘τ’ (τ >48ms) or an increase in the constant for LV chamber stiffness (b >0.27).11
Non-invasive Methods
Conventional non-invasive diagnosis of DHF is obtained by echocardiography and tissue Doppler imaging (TDI). The most important parameter is the so-called E to E-prime ratio (E/E’). An E/E’ >15 is considered abnormal and diagnostic of DHF. An elevated E/E’ ratio (15 >E/E’ >8) is suggestive of LV diastolic dysfunction, and requires additional echo variables for diagnostic evidence of LV
21
Diagnosis of Diastolic Heart Failure
Diagnostic Criteria
The diagnosis of DHF requires the following criteria: signs and symptoms of HF; normal or mildly abnormal systolic LV function; and evidence of LV diastolic dysfunction. However, unlike systolic HF, diagnosing DHF is not a simple process. This is related to both the complexity of the syndrome and the lack of a standardised method to confirm or exclude the diagnosis of DHF. Unlike HF with reduced EF (HFREF), in which one single parameter (i.e. EF <50%) is sufficient to confirm the diagnosis of the syndrome, in HFNEF different diastolic indices have been used to characterise the presence or absence of diastolic HF.10
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