Evaluation of Diastolic Dysfunction Using Cardiac MRI
1. To highlight the importance and study the patho-physiology of diastolic dysfuncion. 2. To study the parameters in diagnosing diastolic dysfunction including their individual strengths and weaknesses. 3. To investigate the role of CMR in evaluation of these parameters.
Dr. Tarun Pandey MD, FRCR. Assistant Professor, MRI Division, University of Arkansas for Medical Sciences
Understanding Normal Cardiac Function
Outline • What is Diastology? – Epidemiology and Pathophysiology of Diastolic Dysfunction.
• Which parameters to study on MRI and how?
• Which parameter to rely on?
LV Pressure
Ejection
– Morphological: Indexed LA volume and Indexed LV mass. – Mitral valve flow-velocity: E/A ratio, Decceleration time. – Pulmonary vein: Systolic and diastolic flow peaks, S/D ratio & A-wave reversal.
IVRT: Isovolumetric relaxation IVCT: Isovolumetric contraction ESV: End Systolic Volume EDV: End Diastolic Volume
SV
IVCT
IVRT
– Strengths and weaknesses of individual parameter.
• What more can be done?
Filling
– Recent advances: Strain imaging.
ESV
The cardiac cycle consists of four phases shown in the diagram. Notice the pressure-vol. changes during the cycle, in particular during IVRT and ventricular filling.
EDV
LV volume
Understanding the Terminology: What is Diastolic Dysfunction?
Understanding Diastolic Function
•
Isovolumetric relaxation Early rapid diastolic filling Diastasis Late diastolic atrial filling
Notice that the Trans-mitral Pressure Gradient (TMPG) is the actual determinant of LV filling. TMPG is influenced by: – LV relaxation – LV compliance (which affects LA pressures)
Ao Pressure
1. 2. 3. 4.
•
Aortic Closure Opening
Diastole, in turn, is divided into four stages:
LV
Peak Exercise
Mitral Closure Opening
LA
IVRT
IVCT
Aortic Closure Opening
Distance
•
Pulmonary Wedge Pressure (mm Hg)
Rest
Peak Exercise
Rest
LV-End Diastolic Volume (ml)
Mitral Closure Opening
Time
The inability to fill the left ventricle, during rest or exercise, to a normal end diastolic volume without an abnormal increase in LV end-diastolic or mean left atrial pressure Or, a failure to increase LVEDV, & therefore cardiac output during exercise represents diastolic dysfunction.
While diastolic heart failure refers to the clinical syndrome of heart failure in the setting of a normal ejection fraction, DD refers to the abnormality of diastolic function regardless of the clinical status of the patient [1].
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8/31/09
Understanding the Problem at Hand: Epidemiology • Both DD and diastolic heart failure are very common, particularly in the elderly population [2]. – The prevalence of asymptomatic DD in individuals > 45 years is approximately 25-30% [3]. – Up to 40% of heart failure patients have DD which is a cause of significant morbidity in this group [4]. The condition often precedes the progression of systolic dysfunction and is a major determinant of the symptoms of patients with systolic heart failure.
• Hence assessment of diastolic LV function and estimation of filling pressures is an important part of the management of patients with heart disease.
Understanding the Pathophysiology of Diastolic dysfunction • Impaired Relaxation – Aging – Ischemia – Cardiomyopathy
