Pulsus Bisferiens

Etiology

The most common causes of pulsus bisferiens are:

• Mixed aortic valve diseases, such as infective endocarditis, rheumatic heart disease, Marfan syndrome, and bicuspid aortic valve[4][5]
• Hypertrophic cardiomyopathy with obstruction (HOCM)

Other causes are:

• Severe aortic regurgitation[2]
• Large PDA (patent ductus arteriosus) or arteriovenous fistula[6]
• Significant mitral valve prolapse
• Rarely seen in normal people with the hyperdynamic circulatory state

Epidemiology

Pulsus bisferiens is commonly seen in mixed aortic disease with severe aortic regurgitation and hypertrophic cardiomyopathy.

• The incidence of aortic regurgitation is high in the fourth to sixth decade of life, increases with age, and is more common in the elderly. It is more common in men (13%) than women (8.5%). The Framingham study reported the prevalence of aortic regurgitation at 4.9% and severe aortic regurgitation at 0.5% in the US population.[7]
• Hypertrophic obstructive cardiomyopathy (HOCM) is the most common genetically inherited heart disease. Prevalence rates of HOCM vary across the globe. The prevalence in the US is 1 in 500 (0.2%), and in Germany is 1 in 1,372 (0.07%).[8][9] Males are affected more compared to females.
• Rheumatic heart disease and bacterial endocarditis are more common in developing countries (Asia, Africa). The incidence of aortic disease is 10 cases per 100,000 to as high as 374 cases per 100,000 in the Pacific and Australia.

Pathophysiology

The mechanism of pulsus bisferiens is not entirely understood. A normal central pulse has two waves; a percussion wave (larger) and a tidal wave (smaller). It is not easy to distinguish them clinically, as it happens in quick succession. But in some pathological conditions, these are exaggerated by a wider mid-systolic gap leading to two distinct waves.

It is postulated that a large, rapidly ejected left ventricular stroke volume is associated with left ventricular changes in pressure over time, resulting in percussion waves. The second wave (tidal wave) is caused by the backpressure exerted by the recoil of arterial musculature. Katz et al. (1927) also described the theory of a venturi effect caused by the high flow of blood in the ascending aorta. This theory has not received much attention from researchers.[2]

• Mixed Aortic Valve Disease: In patients with aortic regurgitation with aortic stenosis, a regurgitant stroke volume results in smaller peak waves (percussion wave), and aortic stenosis results in mid-systolic dip followed by a taller second wave (tidal wave) in systole.
• Hypertrophic Obstructive Cardiomyopathy (HOCM): Rapid ventricular ejection results in a larger percussion wave, whereas outflow obstruction leads to a mid-systolic gap followed by a second smaller tidal wave.[10]
• Patent Ductus Arteriosus (PDA): Newborns presenting with severe PDA (large left-to-right shunt), a large stroke volume results in a taller first wave (percussion wave), and large runoff resulting in a second smaller wave (tidal wave).

History and Physical

Age gives crucial clues to the diagnosis of the disease. The pediatric age group with a palpable pulse with two strokes should indicate PDA with a left to right shunt. The younger patient usually points towards a diagnosis of hypertrophic cardiomyopathy with an obstruction or bicuspid valve disease, whereas mixed aortic valve disease is more common in the elderly population. Pulsus bisferiens can be more pronounced by the Valsalva maneuver.

History

Common clinical presentations are syncope, dyspnea, chest pain, and palpitations. Long-standing problems can remain asymptomatic and present with signs of acute pulmonary edema and heart failure. HOCM can present with sudden cardiac death and life-threatening arrhythmias, especially in younger athletes.[8]

Physical Examination

On palpation of a peripheral pulse (radial artery), two upstrokes distinguished by a mid-systolic gap in the systole are characteristic of pulsus bisferiens.

• Wider pulse pressure is seen in aortic regurgitation.[11]
• Jugular venous pressure (JVP) examination may reveal a classical 'a' wave in HOCM.
• The apex beat is displaced in severe aortic regurgitation, whereas; in HOCM double beats can be felt at the apex.
• Auscultation: On careful cardiac evaluation, various murmurs can be heard during auscultation. The following murmurs can be observed along with pulsus bisferiens, which may clinch the clinical diagnosis. Ejection systolic murmur in the aortic area (aortic stenosis), early diastolic murmur on the left sternum (aortic regurgitation), mid-diastolic or early diastolic low-pitch rumble murmur at the apex (severe aortic regurgitation) which is also called as Austin Flint murmur, ejection systolic murmur along the left parasternal area (HOCM).[12]

Aortic regurgitation can also present with other clinical signs such as blanching and flushing of the forehead and face (lighthouse sign), bobbing of the head synchronous with the arterial pulse (de Musset sign), repeated flushing and blanching of the capillaries in the nail beds (Quincke sign), alternating systolic miosis and diastolic mydriasis in both pupils (Landolfi sign), pulsations of the retinal arteries on the fundoscopic examination (Becker sign), pulsations of the uvula (Muller sign), systolic pulsations of the liver (Rosenbach sign) and spleen (Gerhard sign), a pistol shot sound both during systole and during diastole on auscultation (Traube sign), diastolic-systolic murmur over the femoral arteries (Duroziez murmur).[13]

Evaluation

Serum Biomarkers: High sensitivity troponin T (Tn-T) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels are elevated in bicuspid aortic valve disease.[14]

Chest X-Ray: Chest X-ray can reveal LVH, left atrial enlargement, and heart failure (pulmonary edema).

ECG: Conduction abnormalities, atrial fibrillation (AF,) left ventricular hypertrophy, and left atrial hypertrophy are seen in both aortic valvular disease and HOCM.

2D-Echo: Echocardiography is the main diagnostic tool for diagnosing mixed aortic valve disease and HOCM. Assessment of valve morphology, determination of the aortic regurgitation jet, aortic regurgitation quantification, and measurement of the aortic root and ascending aorta can be done with 2D echocardiography. It helps in left ventricular assessment and measurement of its dimensions in valvular disease and hypertrophic cardiomyopathy. It also can be used to assess the morphology of the aorta and determine the feasibility of aortic surgery or valve repair.[12]

MRI: Cardiac magnetic resonance imaging is increasingly used to assess regurgitant lesion severity and ventricular function. Advances in noninvasive imaging help in objective measurements of valve disease severity, hemodynamic fluctuation, and structural complications. MRI is also used increasingly in accurately quantifying left ventricular (LV) remodeling. Cardiac MRI is the gold standard test in assessing patients with HOCM.[8][15]

CT: Cardiac and vascular CT has become an indispensable tool for the appropriate planning of transcatheter interventions. Useful in acquiring intracardiac and vascular access route dimensions with accuracy.[16]

Nuclear Imaging and Fluoroscopy: The extent of local infectious activity, metabolic activity, and the extent of calcium deposits can be evaluated with nuclear imaging and fluoroscopy.

Treatment / Management

Management of pulsus bisferiens is based on its etiology. Therefore, early diagnosis and referral to cardiologists are crucial to successful management, reducing mortality and morbidity. Mixed aortic valve disease and hypertrophic cardiomyopathy with obstruction are the most common causes of pulsus bisferiens.

Medical Management

• Mixed Aortic Valve Disease: Vasodilators may help symptomatic patients by reducing preload and increasing cardiac output. Rate control and blood pressure control with angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) might help. Beta-blockers may be less beneficial in treating patients with aortic regurgitation.[8]
• Hypertrophic Obstructive Cardiomyopathy (HOCM): β-blockers are the first line of medical management in HOCM. Calcium channel blockers verapamil and diltiazem are beneficial too and are used as second-line in the treatment.[17] ACE inhibitors and ARBs, because of their vasodilating properties, are better avoided. The use of vasodilators is contraindicated.
• Patent Ductus Arteriosus (PDA): Early use of indomethacin, ibuprofen, or acetaminophen to close a PDA soon after birth prevents further complications.[18] Diuretics can be used in treating acute pulmonary edema.

Surgical Management

• Mixed Aortic Valve Disease: Advances in surgical techniques, specifically those associated with valve repair; improved operative results; and enhanced perioperative management strategies, have contributed substantially to better patient outcomes. Valve-sparing surgical repair is becoming popular as a feasible alternative to routine surgeries. Transcatheter aortic valve replacement (TAVR) has revolutionized patients' treatment with symptomatic, severe aortic stenosis (AS) and now provides the least invasive treatment option for many patients.
• Hypertrophic Obstructive Cardiomyopathy (HOCM): Dual chamber pacemaker for severe HOCM and implantable cardioverter-defibrillator insertion may be indicated in the refractory ventricular arrhythmias. The surgical treatment for HOCM is myomectomy, which improves the outcome. Septal alcohol ablation may be effective in 90% of cases of severe HOCM.[19]
• Patent Ductus Arteriosus (PDA): Surgical ligation is indicated in a neonate with significant clinical PDA, but its role is controversial.[20]

Differential Diagnosis

An important differential diagnosis for a bisferiens pulse is a dicrotic pulse. It is always difficult to distinguish between these two clinically. In the dicrotic pulse, two peaks are palpable; one in systole and the other in diastole. Whereas in pulsus bisferiens, both peaks are seen in systole.[21] Dicrotic pulse is seen in cardiac failure and sepsis. Also, it is occasionally seen in normal individuals after exercise.

Prognosis

Mixed Aortic Valve Disease: The prognosis is generally good in patients with isolated severe aortic regurgitation (AR) who are asymptomatic and have a preserved LV function. Patients with moderate to severe AR have poor outcomes. Surgical intervention and aortic valve replacement (AVR) can improve the survival rate in symptomatic patients with LV dysfunction.

Hypertrophic Obstructive Cardiomyopathy (HOCM): The mortality rate is very low for patients with HOCM.[22] Generally, the long-term outcome is good. A small percentage of the population has a risk of sudden cardiac death.

Patent Ductus Arteriosus (PDA): PDA severity scores have been developed, which can be used to predict serious outcomes. Ductus closes spontaneously in most healthy newborns; only 3% of infants weighing more than 1,000 gms may require a PDA intervention.

Complications

Complications in patients who have pulsus bisferiens include:

• Heart failure
• Stroke
• Arrhythmias
• Infective endocarditis
• Sudden cardiac death