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Clinical Evaluation and Diagnosis of Rheumatic Heart Disease
Introduction
Until recently, the diagnosis and evaluation of rheumatic heart disease (RHD) was purely clinical in resource-poor settings where RHD has remained endemic. The advent of portable echocardiographic technology, however, now means that this valuable diagnostic tool is more widely available in resource-poor settings and in remote locations, thus transforming the diagnosis of both acute rheumatic fever (ARF) and RHD. In 2012, the first evidence-based echocardiographic guidelines were published to facilitate early diagnosis of mild RHD in individuals without a previous history of ARF. This was followed by revision of the Jones criteria in 2015 to include echocardiographic findings in the diagnosis of ARF. The most common manifestation of RHD in adults is multivalve and mixed valve disease. Current international guidelines focus on the evaluation of advanced single valve disease with either regurgitation or stenosis as the dominant pathology. A knowledge gap exists regarding the evaluation of multivalve and mixed valve diseases that characterize chronic RHD across the age spectrum.
A detailed review of the pathogenesis of ARF and RHD is presented in Chapter 2 . RHD is the only significant long-term sequela of ARF and predominantly affects the left-sided cardiac valves. Approximately 60% of patients who experience at least one episode of ARF will develop RHD. Although acute rheumatic valvulitis is often reversible, severe single or repeated episodes of ARF often lead to permanent scarring and chronic valvular dysfunction known as chronic RHD. Myocardial impairment and dilatation occur only in the setting of severe valve disease, and recovery can be expected if timely cardiosurgical correction of valvular dysfunction takes place. The initial or recurrent episode of ARF may lead to a prolonged phase of inflammation and requires a long period of rest and recovery. The pericardial effusion seen during the acute phase of ARF usually resolves with no long-term sequelae (see Chapter 3 for a more complete discussion of the clinical features of ARF).
Epidemiology of Rheumatic Heart Disease
In 2015, an estimated 33.4 million people worldwide had RHD, resulting in 319,400 deaths and 10.5 million disability-adjusted life-years lost per annum. Today, RHD predominantly affects those young people who live in marginalized communities or resource-poor settings. Many affected populations live in rural and remote regions, some distance from diagnostic and specialist services.
In childhood, by far the most common lesion in RHD is isolated mitral regurgitation ( Fig. 5.1 ). By adolescence and young adulthood, mixed multivalve disease involving both the aortic and mitral valves becomes the most common manifestation ( Fig. 5.1 ). Isolated aortic valve disease occurs in children but by adulthood it is rare, being more often associated with multivalve pathology ( Fig. 5.1 ). Pure mitral stenosis can occur as young as 10 years old but it is more common during the third and fourth decades of life. Chronic RHD is more common in women than men across all ages with unrecognized RHD affecting many women during their childbearing years leading to preventable morbidity and mortality for both mother and child ( Fig. 5.2 ).
Diagnostic Criteria for Rheumatic Heart Disease
The diagnosis of RHD often occurs late and usually because of complications of the illness, including heart failure (HF), infective endocarditis, arrhythmias, stroke, pregnancy-related complications, or sudden death. A long latent phase of asymptomatic valvular heart disease, often without any preceding history or symptoms of ARF, is the most common scenario. The Global Rheumatic Heart Disease Registry study (REMEDY) showed that the proportion of patients with RHD who had a previous history of ARF is 22.3% in low-income countries, 44.3% in lower-middle-income countries, and 59% of upper-middle-income countries. Low public awareness of ARF and limited access to primary healthcare and diagnostic modalities are likely reasons for this disparity. Additionally, the current diagnostic guidelines may not be sufficiently sensitive to detect ARF in some high-risk populations.
The 2012 World Heart Federation (WHF) diagnostic criteria were developed by multinational collaboration to allow for standardized diagnosis of RHD with a focus on mild RHD in high-risk populations in individuals without a prior history of ARF ( Table 5.1 ). See Chapter 13 for discussions on RHD screening. The WHF definitions for pathologic aortic and mitral regurgitation have been adopted by the Jones criteria writing group to diagnose acute valvulitis in the setting of ARF. The diagnosis of ARF is discussed in Chapter 3 . Patients who present with ARF may have acute or “acute-on-chronic” RHD. This chapter explores the diagnosis of established chronic RHD.
Table 5.1
2012 World Heart Federation Criteria for the Echocardiographic Diagnosis of Rheumatic Heart Disease.
Reproduced from Remenyi et al.
| Echocardiographic criteria for individuals aged ≤20 years | |
| Definite RHD (either A, B, C, or D): | |
| Borderline RHD (either A, B, or C): | |
|
|
| Echocardiographic criteria for individuals aged >20 years | |
| Definite RHD (either A, B, C, or D): | |
| Echocardiographic criteria for pathological regurgitation (all four Doppler criteria must be met) | |
| Pathological MR | Pathological AR |
|
|
| Morphological features of RHD | |
| Mitral Valve | Aortic Valve |
|
|
RHD, rheumatic heart disease; MV, mitral valve; AV, aortic valve; MR, mitral regurgitation; MS, mitral stenosis; AR, aortic regurgitation; AMVL, anterior mitral valve leaflet.
a Congenital MV anomalies must be excluded. Furthermore, inflow obstruction due to nonrheumatic mitral annular calcification must be excluded in adults.
b Bicuspid AV, dilated aortic root, and hypertension must be excluded.
c Combined AR and MR in high prevalence regions and in the absence of congenital heart disease is regarded as rheumatic.
d A regurgitant jet length should be measured from the vena contracta to the last pixel of regurgitant color (blue or red).
e AMVL thickness should be measured during diastole at full excursion. Measurement should be taken at the thickest portion of the leaflet, including focal thickening, beading, and nodularity. Measurement should be performed on a frame with maximal separation of chordae from the leaflet tissue. Valve thickness can only be assessed if the images were acquired at optimal gain settings without harmonics and with a frequency of >2.0 MHz.
f Abnormal thickening of the AMVL is age-specific and defined as follows: ≥3 mm for individuals aged ≤20 years; ≥4 mm for individuals aged 21-40 years; and ≥5 mm for individuals aged >40 years. Valve thickness measurements obtained using harmonic imaging should be cautiously interpreted and a thickness up to 4 mm should be considered normal in those aged ≤20 years.
g Restricted leaflet motion of either the anterior or the posterior MV leaflet is usually the result of chordal shortening or fusion, commissural fusion, or leaflet thickening.
h Excessive leaflet tip motion is the result of elongation of the primary chords and is defined as displacement of the tip or edge of an involved leaflet towards the left atrium, resulting in abnormal coaptation and regurgitation. Excessive leaflet tip motion does not need to meet the standard echocardiographic definition of MV prolapse disease, as that refers to a different disease process. This feature applies to only those <35 years of age. In the presence of a flail MV leaflet in the young (<20 years of age), this single morphologic feature is sufficient to meet the morphologic criteria for RHD (that is, where the criteria state “at least two morphologic features of RHD of the MV” a flail leaflet in a person <20 years of age is sufficient).
i In the parasternal short-axis view, the right and noncoronary aortic cusp closure line often appears echogenic (thickened) in healthy individuals and this should be considered as normal.
Diagnosis of Chronic Rheumatic Heart Disease in Individuals with a History of Acute Rheumatic Fever
In individuals with a confirmed diagnosis of ARF, and once acute inflammation has subsided after weeks to months, as determined by normalization of inflammatory markers, the persistence of pathologic regurgitation of the mitral and/or aortic valves on echocardiography (see Table 5.1 ) is pathognomonic for chronic RHD. In circumstances where echocardiography is not available, one must rely on clinical acumen and the persistence of a mitral and/or aortic regurgitant murmur to confirm the diagnosis of chronic RHD.
Diagnosis of Rheumatic Heart Disease in Individuals Without a History of Acute Rheumatic Fever
Even after screening questions on history, practice shows that most patients in the world are diagnosed with RHD without any previous history of ARF. Reasons for suspecting RHD and initiating a referral for clinical assessment and/or echocardiography may include the following: pathological murmur, exercise-induced chest pain, shortness of breath, HF, syncope, palpitations, atrial fibrillation, or stroke.
For the millions of young people in the world who already have established RHD, their best and most tangible hope for a longer and healthier life is to have their RHD detected at a stage when secondary prophylaxis has the greatest chance of modifying disease outcomes. The 2012 WHF standardized echocardiographic criteria were developed with the aim of achieving rapid and consistent differentiation of mild RHD from normal echocardiographic findings in individuals without a previous history of ARF. The minimum diagnostic criteria in this setting are detailed above in Table 5.1 . Echocardiographic criteria for RHD are based on modalities that are available on basic portable machines: 2D, continuous-wave, and color-Doppler. The 2012 WHF guidelines clearly define what findings are consistent with definite and borderline RHD and also what are considered to be normal echocardiographic findings in children and adults. The guidelines define the morphological features of RHD and also clearly state how to differentiate trivial or physiologic regurgitation from pathologic regurgitation. This differentiation is critically important in RHD where it can influence the decision to prescribe painful and long-term secondary antibiotic prophylaxis.
To diagnose definite RHD on echocardiography in individuals without a history of ARF, both morphologic features of RHD and functional aortic and/or mitral valvular regurgitation and/or stenosis must be present in the absence of congenital heart disease. The only exception to the rule is that in those aged ≤20 years, borderline RHD of both the aortic and mitral valves is classified as definite RHD.
The borderline category only applies to those aged 20 years or younger, and it overlaps with normal findings in school-aged children. The rationale for introducing a borderline category in this age group was to increase the sensitivity in those who live in endemic regions with a high pretest probability of disease. The absolute clinical significance of borderline RHD is yet to be determined, though it is clear that those with borderline RHD are at an increased risk of both disease progression and morbidity.
In those settings where echocardiography is not widely available, the diagnosis of RHD still relies on clinical auscultatory findings of valvular regurgitation or stenosis. Auscultatory findings do not address the etiology of disease and as such the pretest probability of RHD will determine diagnostic and management strategies.
Clinical Assessment and Findings
Mild-to-moderate RHD is almost always asymptomatic in children and young adults. In regions of the world where echocardiography is not widely available, diagnosis and referral to tertiary centers will be based on clinical assessments and findings. Each of the classical lesions is associated with a number of clinical features that help guide the assessment and give guidance regarding severity of disease. Clinical assessment needs to be supplemented with ECG, chest X-ray, and blood tests. Whenever available, echocardiography should be used to validate clinical findings and determine etiology and severity of valvular dysfunction.
Innocent Cardiac Murmurs
Innocent murmurs may complicate the clinical evaluation of high-risk children and adults when cardiac auscultation is used to diagnose RHD. Figs. 5.3 and 5.4 demonstrate comparative phonographs and location of various innocent and pathologic murmurs. Cardiac auscultation is a fundamental process that requires active thought and listening, practice, and ongoing reinforcement of skills.
Innocent murmurs in the pediatric population
In the pediatric population, innocent murmurs occur in up to 25% of school age children on any given day and may confuse the clinical picture ( Table 5.2 ). Patients with innocent murmurs may have RHD, those without murmurs may have RHD, and those with murmurs and congenital heart disease may still have RHD. An Australian study found that doctor identification of any murmur had 38.2% sensitivity, 75.1% specificity, and 5.1% positive predictive value and the corresponding values for pathological murmurs were 20.6%, 92.2%, and 8.3% in relation to RHD.
Table 5.2
Key Differentiating Features on Examination Between Innocent and Pathological Murmurs.
| Innocent | Pathological |
|---|---|
| Usually occur in systole | Can occur in systole, diastole, or both |
| Usually soft or vibratory | Harsh |
| Grade 1/6 or 2/6 only | Grade 1/6–6/6 |
| Normal S1 and S2 | Abnormal S2 |
| Localized and do not radiate | Often radiate |
| No associated clicks or gallops | May be associated with added sounds (e.g., click) |
| Normal apex beat | May be associated with displaced apex beat |
| No parasternal heave or thrill | May be associated with a parasternal heave or thrill |
| Varies with respiration and position, often disappears on standing | Specific variation with respiration and position according to impact of maneuver on lesion |
| Not associated with other signs of heart disease | Associated with other signs of heart disease |
Still's murmur is the most common innocent murmur. It has a low-pitched musical or vibratory quality, best heard at the mid-to-lower sternal border and toward the apex and is not associated with any added sounds. Pulmonary flow murmurs are harsher and high-pitched, heard at the left upper sternal border, are often flow-dependent and vary with position, and disappear with Valsalva maneuver. Venous hum and carotid bruit are also common, but they are more easily distinguished from the pathologic murmurs of RHD. Venous hum is a continuous murmur that is heard below the clavicle and disappears when the patient is positioned supine, while the carotid bruit is localized to the carotid artery with or without any radiation. Innocent murmurs are associated with normal ECG and chest X-ray findings.
Pathological Murmurs in the Pediatric Population
The differentiation of innocent from pathological murmurs comes with critical thinking and assessment. The subtle differences lie in quality, pitch, location and radiation, added sounds and clicks, whilst dynamic maneuvers and positioning may assist ( Table 5.2 ). In childhood, common congenital heart defects such as ventricular septal defects, atrial septal defects, pulmonary stenosis, and aortic stenosis (AS) are associated with pathological murmurs and require differentiation from RHD. Regurgitant lesions because of congenital mitral valve and aortic valve disease are less common, and echocardiography is usually required to differentiate congenital from rheumatic etiology.
Pathological Murmurs in the Adult Population
In the adult population, degenerative and acquired processes become the leading cause of pathological valvular disease. On clinical history and examination alone, it is often difficult to determine the etiology of valvular disease: consideration should be given to the age of the patient and to background prevalence of RHD, particularly when clinical decisions are made without the aid of echocardiography. Clinical findings in the diagnosis of RHD in regions without access to echocardiography remain critically important. The examination findings in severe RHD have been summarised in Table 5.3 .
Table 5.3
Clinical Features Suggestive of severe Valvular Lesions on Clinical Examination.
| Mitral | Aortic | |||
|---|---|---|---|---|
| Regurgitation a | Stenosis a | Regurgitation a | Stenosis a | |
| Apex | Thrusting ± thrill Inferolaterally displaced |
Tapping Undisplaced |
Thrusting Inferolaterally displaced |
Heaving Minimally displaced |
| Pulse | Normal or jerky Commonly atrial fibrillation |
Normal or low volume Often atrial fibrillation |
Collapsing (or “water-hammer”) See also box 5.1 |
Slow-rising |
| Heart sounds | Soft S1 Occasional S3 |
Loud S1 Short gap between S2 and the opening snap |
Normal/soft S2 Occasional S3 |
Quiet or absent S2 Reversed split S2 |
| Murmur | Does not correlate with severity | Long mid-diastolic murmur | Short early-diastolic murmur Austin Flint murmur |
Does not correlate with severity |
| Other features | Evidence of left heart failure Carey Coombs murmur Signs of pulmonary hypertension b |
Pulmonary congestion and right heart failure Signs of pulmonary hypertension b |
Evidence of left heart failure Wide pulse pressure |
Evidence of left heart failure |
a In mixed valve disease, the dominant lesion can be determined by assessing the impact of any lesion on the above parameters. In mixed mitral valve disease, the most discriminating factors are the apex beat and auscultatory findings; in mixed aortic valve disease, it is the apex beat, pulse character, and blood pressure. In multivalve disease involving mitral and aortic regurgitation, the key discriminating features are the pulse and blood pressure: sinus rhythm in the presence of a high systolic BP and wide pulse pressure suggests that aortic regurgitation is the dominant lesion. In those with significant mitral stenosis, clinical signs of aortic valve disease may be less evident. On the other hand, if there is evidence of a severe aortic valve lesion in the context of mitral stenosis, this suggests that the mitral stenosis is not severe.
b Right ventricular parasternal heave, loud pulmonary component of S2 (P2), palpable (P2), murmur of tricuspid regurgitation, right heart failure.
Mitral Regurgitation
Clinical symptoms
Mitral regurgitation (MR) is the most common manifestation of RHD. Symptoms develop as a result of increasing left atrial pressure, pulmonary venous hypertension and increased left ventricular (LV) end diastolic volumes and pressure. The acuity of the change in physiology often determines the severity of the symptoms and their recognition by patients and family members. Shortness of breath, especially during peak physical activity, may progress to shortness of breath at rest followed by clinical decompensation with HF and death. More rapid progression can occur in the setting of acute-on-chronic mitral valve disease or during significant intercurrent illnesses (see Chapter 16 ).
Clinical signs: mild-to-moderate mitral regurgitation
The hallmark of chronic MR is a harsh pansystolic murmur ( Fig. 5.5 ) heard best at the apex with radiation to the axilla. The direction of the regurgitant jet is usually posterolateral (hence the radiation to the axilla) due to the typical retraction of the posterior mitral valve leaflet and prolapse of the anterior leaflet. It is often high-pitched, and the intensity does not increase with inspiration, unlike the murmur of tricuspid regurgitation (TR). Less commonly, posterior mitral valve leaflet prolapse leads to an anteriorly-directed jet of MR with the pansystolic murmur heard medially at the lower left sternal edge. The LV apex will not be displaced in the setting of mild to moderate disease.
Clinical signs: moderate-to-severe mitral regurgitation
With progression of MR and ongoing ventricular dilatation, the apex beat becomes displaced laterally and inferiorly toward the axilla ( Table 5.3 ). An associated middiastolic murmur related to increased transmitral flow may develop. This is often called as a Carey-Coombs murmur. It is heard best with the bell of the stethoscope, while the patient is in the left lateral position and the breath held in end-expiration. In the setting of significant left atrial dilatation, atrial fibrillation may develop leading to an irregularly irregular heartbeat.
Electrocardiogram
If there is acute valvulitis, the ECG may reveal first-degree heart block with a prolonged PR interval and or higher degrees of AV block (refer to age-specific normal ranges - see Chapter 3 ). In chronic RHD, the ECG is normal with mild-to-moderate mitral regurgitation. Moderate-to-severe disease often leads to classic ECG findings of left atrial enlargement with upright P waves in lead I, a bifid P wave in leads V1–V6 that gives the “M” pattern of P-mitrale. LV dilatation and hypertrophy leads to increased LV voltages ( Fig. 5.6 ). Right axis deviation (negative QRS in lead I), positive QRS complexes (dominant R-waves) in V1-2 (suggesting right ventricular hypertrophy), ST depression and T wave inversion in V1-3 (suggesting right ventricular strain), and peaked P waves (P pulmonale, suggesting right atrial hypertrophy) may appear in the setting of severe pulmonary hypertension.
Chest X-ray
Chest X-ray (CXR) is normal in the setting of mild RHD, and it is helpful to exclude noncardiac pathologies that are common in resource-poor settings. As disease progresses, the CXR will demonstrate LV dilatation with cardiomegaly, left atrial enlargement with splaying of the carina, and pulmonary congestion with plethora if the MR is severe ( Fig. 5.7 ).
Mitral Stenosis
Clinical symptoms
Pure mitral stenosis (MS) is rare in the first decade of life; however, it becomes more common during childbearing years and has significant implications for pregnancy. The symptoms of pregnancy and MS overlap (see Chapter 9 ). Symptoms of MS develop as a result of progressive obstruction to LV inflow. The diastolic gradient between the left atrium and left ventricle is worsened with increased flow and heart rate, such as during illness, exercise or pregnancy, as well as in the presence of atrial fibrillation with a rapid ventricular rate. There is a clear correlation between the effective mitral valve orifice size and symptom onset and progression. Initial symptoms of progressive exertional dyspnoea usually develop with a mitral valve area <2 cm 2 , with the other symptoms of HF including orthopnoea and paroxysmal nocturnal dyspnoea manifesting as size decreases to <1.5 cm 2 . At advanced stages with massive left atrial enlargement, signs of cough, hemoptysis, chest pain, palpitations, and a hoarse voice (due to the left atrium mechanically compressing the left recurrent laryngeal nerve, known as Ortner's syndrome) begin to develop. Less commonly, patients present with symptoms related to arterial embolism from the left atrium, such as an ischemic stroke or peripheral arterial occlusion.
Clinical signs: mild to moderate
The clinical signs of MS include an opening snap followed immediately by a low-pitched, diastolic rumble or decrescendo murmur heard best at the apex with the patient in a left lateral position ( Fig. 5.8 ). It is again accentuated by increasing heart rate with mild exercise. The duration of the murmur correlates with the severity of the MS. The opening snap is produced as the valve opens under the high left atrial pressures. The second phase of the murmur is in late diastole, as a result of atrial contraction, occurring immediately before the S1 sound creating a late diastolic, crescendo murmur. In the presence of atrial fibrillation, the active LV filling phase does not take place and the latter part of the MS murmur disappears.
Clinical signs: moderate to severe
As MS worsens, left atrial pressure increases, forcing the mitral valve open earlier in diastole and the opening snap occurs earlier as does the initial decrescendo part of the murmur. Furthermore, as pulmonary hypertension increases, the pulse becomes small in volume and a right ventricular parasternal heave and loud or even palpable P2 become more prominent ( Table 5.3 ). Less commonly patients may have signs of systemic embolism from the left atrium, especially if they have previously had episodes of atrial fibrillation, which further increases stroke risk in MS.
Electrocardiogram
It is important to confirm the baseline rhythm, namely sinus rhythm or atrial fibrillation. Atrial fibrillation is rare under 20 years old even in the setting of severe MS. Voltage criteria for left atrial enlargement, P-mitrale, and right ventricular hypertrophy are markers of severe disease.
Chest X-ray
Chest X-ray will demonstrate left atrial enlargement with a bulge sitting above the heart border in the left mediastinum with a splaying of the carina. Upper lobe diversion of blood flow and/or pulmonary congestion occurs in the setting of worsening HF. Calcification of the mitral valve apparatus may be seen on lateral CXR, especially in older patients. In the setting of established pulmonary hypertension, the main and hilar pulmonary arteries become prominent and there is also right ventricular hypertrophy on CXR.
Mixed Mitral Valve Disease
Clinical symptoms
With progression of RHD, severe mixed MS and MR often develops. The symptoms are insidious but are consistent with chronic progressive shortness of breath at rest, which is worse with any exertion. Exercise tolerance is often limited, and individuals will often self-limit activity. If pulmonary hypertension is present, then it may be associated with perioral cyanosis with activity.
Clinical signs: moderate to severe
There is both a short harsh pansystolic murmur at the apex and a short decrescendo diastolic murmur ( Fig. 5.9 ). Signs of pulmonary hypertension are usually present. Particular attention to the apex beat and auscultatory findings can help to determine which lesion is dominant ( Table 5.3 ).
Electrocardiogram
Voltage criteria for left atrial enlargement and right ventricular hypertrophy are markers of severe disease together with right ventricular strain.
Chest X-ray
Chest X-ray will demonstrate left atrial enlargement with a bulge sitting above the heart border in the left mediastinum with a splaying of the carina, upper lobe diversion of blood flow, and/or pulmonary congestion in the setting of worsening HF. In the setting of established pulmonary hypertension, the main and hilar pulmonary arteries become prominent on CXR.
Aortic Regurgitation
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