Diastolic heart failure

Introduction to diastolic heart failure Diastolic heart failure (DHF) refers to a clinical syndrome of pulmonary circulation or systemic circulation due to abnormal ventricular filling and elevated filling pressure in the case of normal ventricular systolic function. basic knowledge The proportion of illness: 0.0025% Susceptible people: no special people Mode of infection: non-infectious Complications: arrhythmia multiple lung infections renal insufficiency

Causes of diastolic heart failure

(1) Causes of the disease

The causes of simple left ventricular diastolic heart failure can be generally divided into four categories: 1 diseases affecting left ventricular relaxation: such as hypertensive heart disease, hypertrophic cardiomyopathy, aortic stenosis, ischemic heart disease, Cardiac and diabetes in the elderly, 2 diseases affecting left ventricular stiffness: such as myocardial amyloidosis, hemochromatosis, restrictive cardiomyopathy, myocardial interstitial fibrosis and endocardial fibrosis, 3 affecting interventricular interaction Disease: such as increased right ventricular volume load (atrial septal defect), increased right ventricular pressure load (pulmonary hypertension) and acute right ventricular dilatation (such as acute tricuspid regurgitation, right ventricular infarction, acute pulmonary embolism, etc.), 4 affect left Room-filled diseases: such as constrictive pericarditis, massive pericardial effusion and pericardial tamponade, and rapid ventricular tachycardia (due to the absence of abnormalities in the left ventricular self-diastolic function in such diseases, There is also dissent as a cause of diastolic heart failure).

Below we introduce the most common diseases that cause left ventricular diastolic heart failure:

Hypertension

Hypertension is one of the major risk factors for diastolic heart failure. 25% of asymptomatic hypertensive patients have diastolic dysfunction, and 90% of hypertensive patients with left ventricular hypertrophy have diastolic dysfunction. Clinical studies have shown that most of these patients are Early diastolic ventricular filling is impaired, atrial compensatory, diastolic ventricular filling is enhanced, and early diastolic filling loss is usually associated with increased afterload and increased ventricular weight. Impaired diastolic function in hypertensive patients involves multiple mechanisms: 1 ventricular dysfunction : Hypertensive patients can have diastolic dysfunction before cardiac structural abnormalities, mostly myocardial dysfunction leading to isovolumic dysfunction, isovolumic dysfunction, prolonged isovolumic relaxation time, left ventricular pressure drop slowly, early diastolic ventricular filling Decreased, atrial filling compensatory increase, in addition, when hypertensive cardiac hypertrophy, even without coronary artery abnormalities, subendocardial myocardial ischemia may worsen ventricular diastolic function, when there is indoor differential conduction or bundle branch block, Ventricular heterogeneity will also reduce ventricular flaccid rate, 2 myocardial stiffness increased : Left ventricular hypertrophy is a compensatory manifestation of increased post-load stress in patients with elevated blood pressure. Increased afterload can promote cardiomyocyte growth and phenotypic changes through direct mechanical stimulation and neuroendocrine pathways such as AngII, collagen production, and ultimately increase ventricular weight. Increased myocardial stiffness, diastolic dysfunction, hypertensive patients can develop from simple diastolic dysfunction to systolic dysfunction, hypertension in patients with atrial development from compensatory to decompensated atrial enlargement, atrial systolic function decline and atrial fibrillation Atrial contraction filling accounts for about 40% of the total filling. Atrial decompensation will promote ventricular diastolic dysfunction to the development of typical heart failure. The development of hypertensive patients generally goes through several stages: 1 asymptomatic, but with diastolic filling abnormalities; 2 symptoms, filling pressure increased, although the systolic function is normal, there are signs of pulmonary congestion; 3 left ventricular filling is insufficient to lead to decreased cardiac output; 4 gradually develop to systolic and diastolic dysfunction, manifested as congestive heart failure.

2. Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is considered to be the prototype of diastolic heart failure. Left ventricular hypertrophy is closely related to maximum diastolic filling. In addition, it is also affected by ventricular geometry (increased wall thickness/diameter ratio), myocardial ischemia and fibrosis. The influence of other factors, cardiac hypertrophy, myocardial arrangement disorder, myocardial interstitial fibrosis increased cardiac stiffness, and hypertrophic cardiomyopathy patients with myocardial flaccid disorder related to the following factors: 1 early diastolic pressure gradient and contraction load changes; Calcium overload secondary to myocardial ischemia; 3 even if the left ventricle is mild to moderate hypertrophy, there may be transient local motion inhomogeneity.

3. Coronary artery disease

It has been reported that about 90% of patients with coronary artery disease have diastolic dysfunction. Various forms of myocardial ischemia impair myocardial diastolic function and filling through various mechanisms. Myocardial ischemia in patients with angina pectoris is paroxysmal and reversible, accompanied by the onset of angina pectoris. Reversible ventricular diastolic dysfunction, leading to increased left ventricular diastolic blood pressure and dyspnea, the experimental model confirmed that its mechanism is mainly impaired myocardial flaccid function, myocardial ischemia energy supply disorder, ATP production disorder leads to: 1 diastolic Ca2 Increased concentration; 2 forms a reversible tight combination; 3 temporary increase in local heterogeneity, myocardial ischemia is the first manifestation of diastolic dysfunction, only persistent ischemia and local ventricular dyskinesia, causing systolic dysfunction, About 60% of patients with acute myocardial infarction have diastolic dysfunction. Diastolic dysfunction is the earliest change of acute myocardial infarction. The diastolic pressure-capacity curve is upward and shifts to the right, 40% of which is flaccid dysfunction, and 25% is Restricted diastolic dysfunction, its occurrence may be related to the following factors: myocardial cell calcium super Load, ventricular relaxation is delayed and incomplete, atrial or ventricular volume increases, left ventricular activity is uneven, left and right ventricular interaction, pericardial ventricular relaxation, valvular dysfunction, and myocardial structure changes after myocardial infarction: Alternative fibrosis, residual cardiomyocyte hypertrophy, collagen network remodeling, myocardial cell rearrangement, will increase myocardial stiffness, hinder left ventricular filling, in addition, myocardial stunning and myocardial hibernation patients also have ventricular dysfunction, and lack The extent of blood is related to duration.

4. Valvular heart disease

Patients with valvular heart disease have left ventricular hypertrophy and eccentric hypertrophy due to long-term pressure and volume load, and impaired diastolic function. The mitral or aortic regurgitation causes an increase in volumetric load, resulting in diastolic wall stress. Increase, left ventricular enlargement, aortic valve stenosis caused by increased pressure load, increased ventricular wall stress during systole, ventricular hypertrophy, both forms of ventricular hypertrophy are associated with ventricular dysfunction, but ventricular stiffness is only in centripetal Increased when hypertrophy, but decreased in eccentric hypertrophy, diastolic dysfunction occurs in the early stage of valvular heart disease, followed by systolic dysfunction, after the valve replacement surgery, although the left ventricular myocardial weight and EF value returned to normal, during exercise Diastolic dysfunction can still last for years.

5. Diabetic heart disease

Although there is no clear clinical manifestation of coronary atherosclerotic heart disease and hypertension, heart failure often occurs in diabetic patients, of which 30% to 50% show flaccid delay, prolonged isovolumic relaxation time, heart changes and other complications in diabetic patients Similarly, it is related to the pathological changes of connective tissue. Therefore, the basic characteristics of patients with diabetic heart disease are active flaccidity and mild compliance with passive compliance, but often combined with systolic dysfunction and decreased EF.

6. Constrictive pericarditis and restrictive cardiomyopathy

Constrictive pericarditis is pericardial fibrosis, stiffness and calcification bind the heart, limiting the diastolic filling of the four heart chambers, and restrictive cardiomyopathy is endocardial, myocardial fibrosis, or abnormal myocardial tissue deposition. The stiffness of the wall was increased, and the diastolic dysfunction was significant in the middle and late diastole. The hemodynamic changes were similar. The ventricular filling was blocked, the ventricular end-diastolic pressure was increased, and the pressure curve showed early diastolic subsidence. Pulmonary arterial pressure and pulmonary artery resistance increased, and cardiac output decreased.

(two) pathogenesis

1. Diastolic dysfunction of the heart refers to the ability of the heart to return to the original end-diastolic volume and pressure after contraction, including ventricular relaxation and ventricular compliance, and is regulated by neurohumoral and load factors. Ventricular ventricular relaxation is an initiative. Energy-consuming process: The process includes three periods of diastolic, isovolumic diastolic, and rapid filling of the ventricle. The functional damage mechanisms are:

(1) Calcium ion-reduction disorder: When myocardial repolarization, sarcoplasmic reticulum, mitochondria actively reduce Ca2 capacity, Ca2 reset delay, seen in: 1ATP deficiency, affecting calcium pump function; 2 calcium pump ATPase activity decreased; 3 sarcoplasmic The net intake of Ca2 was significantly reduced; 4 calcium overload.

(2) Muscle-actin assembly dissociation disorder: myocardial relaxation first needs to remove the transverse bridge, that is, with the participation of ATP, Ca2 detaches to form myosin-ATP and actin, when 1Ca2 resets delayed; 2 muscle calcium The protein has an increased affinity for Ca2; when 3ATP is deficient, the dissociation disorder leads to diastolic dysfunction.

(3) Ventricular diastolic load reduction: the factors that determine the ventricular diastolic load in normal people include the change of geometric shape during ventricular contraction, the volume reduction and the late resistance of cardiac ejection, etc. The more obvious the geometrical reduction, the greater the diastolic potential energy formed, and the diastolic The more complete, and vice versa, the higher the endurance of the ejection increases the myocardial pressure and impedes diastole.

(4) The degree of myocardial damage is different: the myocardial relaxation is in time, the spatial expression is uneven, the local diastolic function is not coordinated, and the diastolic function is reduced.

2. Ventricular compliance reduces ventricular compliance refers to the change in volume caused by changes in unit pressure. Ventricular compliance begins at the end of the rapid filling phase and ends at the beginning of the next cardiac cycle. It is a passive process and the stiffness of the ventricle. It refers to the pressure change that can be caused by the change of unit volume. The common ventricular end-diastolic pressure-volume curve indicates that the ventricular compliance and ventricular stiffness are reciprocal, and the factors leading to the decline of ventricular compliance are:

(1) Pericardial factors: including constrictive pericarditis and pericardial effusion.

(2) Endocardial factors: Endocardial hyperplasia and fibrosis can affect cardiac diastolic function, such as endocardial fibrosis and eosinophilic endocarditis.

(3) Intracardiac factors: hyperplasia (such as hypertension), abnormal substance deposition and infiltration (such as amyloid and iron deposition infiltration), inflammatory cell infiltration, etc. lead to increased ventricular weight or cardiac hypertrophy, myocardial edema, myocardial stiffness increase.

Diastolic heart failure prevention

Left ventricular diastolic dysfunction is often earlier than systolic dysfunction. From this point of view, early measures to protect the myocardium are beneficial, and early diagnosis and treatment of diastolic failure have important clinical significance.

Diastolic heart failure complications Complications, arrhythmia, multiple lung infection, renal insufficiency

Complications of diastolic heart failure are similar to complications of systolic heart failure, but also arrhythmia, pulmonary infection, liver dysfunction, renal insufficiency, water and electrolyte disturbances.

Symptoms of diastolic heart failure Common symptoms Systolic murmurs Pulmonary congestion Lower extremity diffuse edema Qi stagnation Diastolic galloping escape bloating dyspnea dyspnea labor dyspnea

Symptom

Simple or early diastolic heart failure may only be manifested as symptoms of pulmonary congestion such as resting or exertional dyspnea. Patients with systolic heart failure or persistent diastolic heart failure may have symptoms of heart failure, both breathing difficulties and shortness of breath. Such as left heart failure symptoms, abdominal distension, oliguria and lower extremity edema and other right heart failure, the latter is due to ventricular diastolic dysfunction and sympathetic nervous system, increased renin-angiotensin-aldosterone system activity, leading to water Sodium retention further aggravates pulmonary circulatory congestion and presents with circulatory congestion. The symptoms of diastolic heart failure resemble symptoms of systolic heart failure. The odds of occurrence are similar and sometimes difficult to identify clinically.

2. Signs

There are not many characteristic signs of simple or early diastolic heart failure. The breath sounds of both lungs can be weakened, and the bubbling sounds of the lungs are heard. The heart sounds are often not enlarged, and can be heard and diastolic, but they often Cardiac signs of coexistence, such as hypertensive heart disease, diastolic heart failure can have apical beats, apex can be heard and systolic murmur, aortic valve second tone hyperthyroidism; obstructive hypertrophic cardiomyopathy can be in the sternum The fourth intercostal space on the left edge smells coarser systolic murmur; aortic stenosis can smear the systolic murmur in the first auscultation area of the aortic valve; ischemic heart disease may be accompanied by the first heart of the apex Low-pitched, pathological third heart sound, etc., combined with systolic heart failure or persistent diastolic heart failure, the signs are similar to typical congestive heart failure, mainly left and right heart failure signs plus primary heart disease Signs, you can find out by careful examination.

Examination of diastolic heart failure

Blood test: It can be found whether the patient's hemoglobin is normal, whether there is hyperlipemia, hyperglycemia and hyperviscosity.

X-ray inspection

X-ray examination of simple diastolic heart failure can detect pulmonary congestion or pulmonary edema, such as increased lung texture and thickening, interstitial edema, but generally not helpful in identifying contractile or diastolic heart failure, patients with simple diastolic heart failure The heart shadow is generally normal. If it coexists with systolic heart failure, there may be X-ray signs of primary heart disease and enlarged heart chamber.

2. ECG

Electrocardiographic changes were non-specific, and the most common changes in simple diastolic heart failure were P-wave broadening, increased and left ventricular hypertrophy.

3. Heart mechanical diagram

Simultaneous recording of electrocardiogram, heart sound map and apical beat map can be measured to reflect the time interval of left ventricular diastolic performance and some changes in value, diastolic diastolic period can be seen in diastolic heart failure, rapid filling period and prolonged filling time, a The /H ratio and the diastolic amplitude time index (DATI) increase.

4. Echocardiography

It is most valuable for the evaluation of diastolic heart failure and can provide important clues to cardiac structural and functional abnormalities: 1 structurally, left ventricular morphological abnormalities such as hypertension, aortic stenosis and other centripetal hypertrophy; hypertrophic type Asymmetric hypertrophy caused by cardiomyopathy; elderly patients can present a careful cavity, moderate thickening of the ventricular wall, that is, the upper part of the ventricular septum protrudes into the left ventricular outflow tract, and even constitutes a narrow; invasive cardiomyopathy, especially cardiac amyloidosis, It can show the thickening of the biventricular chamber wall, the symmetry of the left ventricular wall, the myocardial speckle echo and other tissue features; the right ventricular pressure or volume overload can cause the left ventricular septum and the right ventricle to change geometrically, diastolic In patients with dysfunctional heart failure, although the left ventricular cavity is normal or small, the left atrium often has different degrees of increase. In 2 patients, the systolic function of patients with diastolic heart failure is generally good, and the left ventricular ejection fraction (LVEF) is mostly normal. Some patients with hypertrophic cardiomyopathy have a LVEF of more than 70%.

M-mode echocardiography was used to detect the E-peak of the anterior mitral curve. The peak value of A peak can be used to judge left ventricular diastolic function. The E/A ratio <1 indicates left ventricular diastolic dysfunction, and Doppler measures mitral blood flow. Spectrum is a simple and easy-to-use method for evaluating diastolic function, revealing left ventricular diastolic dysfunction and its progression, early diastolic velocity peak (EPFV), late diastolic blood flow (APFV), and diastolic early and late flow velocity peak ratio (EPFV) /APFV) and early diastolic peak deceleration (DC) are commonly used indicators. EPFV, DC reduction, APFV increase, EPFV/APFV is less than 1 in patients with diastolic heart failure, in addition, when left ventricular relaxation is reduced, etc. The duration of the diastolic time (IVRT) is prolonged; when the left ventricular stiffness increases, the IVRT is shortened; when the left ventricular relaxation and stiffness are abnormal, the mitral blood flow spectrum can be pseudo-normalized, advanced, and the heart rate is accelerated ( More than 90 times/min) false positives may occur when the left ventricular preload is reduced or the afterload is increased.

The measurement of atrioventricular plane displacement (AVPD) was originally used to evaluate systolic function by M-mode ultrasound at the apical four-chamber view of the interventricular septum and the anterior mitral anterior border, left ventricular wall and apex. The maximum displacement of the systolic atrioventricular plane was recorded at the junction of the posterior lobes of the posterior lobes and in the anterior ventricle, and at the junction of the posterior wall and the mitral valve leaflets. In 1992, Alam et al evaluated by AVPD. Left ventricular diastolic function, patients with left ventricular diastolic dysfunction often show an increase in the proportion of AVPD values due to atrial contraction in the total AVPD value, and this change and measurement of mitral blood flow with pulsed Doppler There is a good correlation between the A/E ratio changes in the spectrum. Pulmonary venous blood flow spectrum analysis is also helpful to evaluate left ventricular diastolic function. Most normal human pulmonary venous blood flow spectrum is a three-phase peak, from the contraction peak (S), diastolic peak (D) And atrial contraction peak (A) composition, normal S is lower than D, but the measured value is close (reference value is 0.55m / s); A is small, about 0.18m / s, patients with left ventricular diastolic dysfunction Right upper pulmonary vein blood flow spectrum S value rise D value decreases, S/D ratio increases, and A value increases. This abnormality is closely related to left ventricular structure and function. Acoustic quantification (AQ) method produces left ventricular area change with time by automatically detecting endocardial border. Curve and area change rate (dA/dt) versus time curve, the latter is bimodal, ie, early diastolic peak filling rate and late diastolic filling rate, pulse Doppler ultrasound measurement of mitral blood flow spectrum can be found, The E/A ratio decreased, while the AQ method found a decrease in the peak filling ratio/late filling ratio. In some patients with mild hypertension without left ventricular hypertrophy, the pulsed Doppler ultrasound left ventricular filling parameters were in the normal range, while the AQ method E-peak acceleration time (AT) prolongation and early filling time prolongation can be detected. Pulsed Doppler myocardial imaging (DMI) technique can detect different myocardial nodes by placing sampling volume in different myocardial segments for on-line quantitative analysis. The extent and extent of segmental damage, the more myocardial segments involved in diastolic dysfunction, the greater the damage to the left ventricular global diastolic function. In addition, the load test can be used to improve patients with early diastolic dysfunction. Detection rates, such as grip force echocardiography, can be used for the diagnosis of potential diastolic dysfunction and myocardial ischemia in hypertensive patients. The results of echocardiography for left ventricular diastolic function are affected by many factors such as the volume of the sample volume, the speed of sound and blood. The angle of the flow direction, age, biochemical and metabolic factors (plasma brain natriuretic peptide, plasma atrial natriuretic peptide, etc.), drugs [such as angiotensin-converting enzyme (ACE) inhibitors], etc., must be combined with clinical, Comprehensive analysis of cardiac morphology and function data.

5. Radionuclide development

The main observations of peak filling rate (PFR) and peak filling time (TPFR), from the left ventricular time-radiation activity curve can be measured in patients with diastolic heart failure, left ventricular diastolic PFR decreased, TPFR prolonged, suggesting diastolic dysfunction, in addition The 1/3, 1/2, 2/3 filling fraction of diastolic dysfunction in patients with diastolic dysfunction (the ratio of filling to total filling in the first 1/3, 1/2, 2/3 filling time, respectively) decreased .

6. Cardiac catheterization

Patients with diastolic heart failure may have a significant decrease in left ventricular pressure drop rate (-dp/dt) and its maximum value (-dp/dtmax), a prolonged T value, and an increase in left ventricular stiffness dp/du, myocardial stiffness The constant KP, ie the slope of the relationship between ventricular stiffness and its pressure (dp/du-1), increases.

7. Exercise test

Early diastolic heart failure may have no clinical manifestations, but may have exercise tolerance, which is milder than systolic heart failure.

Diagnosis and differentiation of diastolic heart failure

diagnosis

The following criteria are available for reference: 1 clinical causes of left ventricular diastolic dysfunction, such as hypertension, coronary heart disease, diabetes, hypertrophic cardiomyopathy, aortic stenosis, endocardial fibroelastosis, etc., 2 patients have static Difficulty or labor dyspnea, 3 physical examination and X-ray examination showed pulmonary congestion and heart does not enlarge, 4 echocardiographic abnormalities, currently used E / A ratio greater than l to determine left ventricular diastolic dysfunction, but severe diastolic function can be There is a pseudo normalization of the E/A ratio. Other echocardiographic charts have left atrial enlargement and left ventricular hypertrophy, but the left ventricular internal diameter is not large, and the left ventricular systolic function is normal or near normal. 5 Excluding other can cause dyspnea (such as merger Mitral regurgitation), 6 if necessary for diagnostic treatment, such as traditional anti-heart failure treatment is not effective and use calcium antagonists or beta blockers effective, may further suggest simple diastolic heart failure .

Differential diagnosis

The disease should be differentiated from systolic heart failure and chronic lung disease.

1. systolic heart failure: there may be rest or exertional dyspnea, but it often has symptoms and signs of systemic congestion, the heart chamber cavity is enlarged, the heart wall is thinner, the ejection score is <50%, traditional Anti-heart failure treatment is effective.

2. Chronic lung disease: Chronic obstructive emphysema, diffuse pulmonary fibrosis, pneumoconiosis, etc. may have symptoms of dyspnea, but these diseases often have a history of respiratory diseases, and may have a right heart system change later, and left There are no abnormalities in the ventricles.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.