Heart Failure with Preserved Ejection Fraction
This patient has heart failure with preserved ejection fraction (HFpEF), answer (b). The combination of classic heart failure symptoms (dyspnea, orthopnea, paroxysmal nocturnal dyspnea), physical findings of congestion (basal crackles), a normal ejection fraction of 55%, left ventricular hypertrophy, and longstanding hypertension definitively establishes this diagnosis 1.
Clinical Reasoning
Why HFpEF is the Correct Diagnosis
Normal ejection fraction with heart failure symptoms: The patient has an EF of 55%, which is preserved (≥50%), yet presents with classic congestive symptoms including dyspnea, orthopnea, and paroxysmal nocturnal dyspnea 1, 2.
Left ventricular hypertrophy from hypertension: The echocardiogram shows LVH, and the patient has uncontrolled hypertension (170/100 mmHg). The vast majority of HFpEF patients have a history of hypertension with evidence of LVH on echocardiography 1.
S4 gallop indicates diastolic dysfunction: The S4 heart sound reflects atrial contraction against a stiff, non-compliant left ventricle—a hallmark of diastolic dysfunction that characterizes HFpEF 1.
Physical examination confirms volume overload: Basal lung crackles indicate pulmonary congestion from elevated left ventricular filling pressures 1.
Age and demographics fit the profile: At 68 years old, this patient fits the typical HFpEF demographic, which is most prevalent among elderly patients with hypertension 1, 2.
Why Other Options Are Incorrect
Heart failure with reduced ejection fraction (HFrEF) is excluded because the EF is 55%, which is normal. HFrEF requires an EF <50% by definition 1, 2.
Ischemic cardiomyopathy is ruled out by the absence of focal wall motion abnormalities on echocardiogram. Ischemic cardiomyopathy results from myocardial infarction and would show regional wall motion abnormalities (hypokinesis, akinesis, or dyskinesis) in the distribution of affected coronary arteries 1.
Cor pulmonale with right ventricular failure is not supported by the clinical picture. This patient has left-sided heart failure symptoms and findings (pulmonary congestion, S4 gallop, LVH). There is no mention of right ventricular dysfunction, elevated jugular venous pressure, peripheral edema, or primary pulmonary disease that would cause cor pulmonale 1.
Pathophysiology of HFpEF
Diastolic dysfunction is the primary mechanism: HFpEF is characterized by reduced ventricular compliance, prolonged isovolumetric LV relaxation, slow LV filling, and elevated LV end-diastolic pressure despite preserved systolic function 1, 3.
Hypertension drives structural remodeling: Chronic hypertension leads to LVH and increased myocardial stiffness due to fibrosis, which impairs diastolic relaxation and compliance 1, 4.
Multiple pathophysiologic contributors: Beyond myocardial stiffness, abnormal renal sodium handling and arterial stiffness play important roles in many patients 1.
Diagnostic Confirmation
The diagnosis is already established based on the clinical presentation and echocardiographic findings, but additional supportive features include:
Elevated natriuretic peptides: BNP or NT-proBNP would be elevated in this symptomatic patient 3, 5.
Diastolic dysfunction parameters on echocardiography: Abnormalities of mitral inflow pattern, tissue velocities (e'), or E/e' ratio would confirm elevated LV filling pressures 1.
Left atrial enlargement: LA volume index >34 mL/m² would indicate chronically elevated LV filling pressures 1.
Common Pitfalls to Avoid
Do not dismiss heart failure because EF is normal: Approximately 40-60% of all heart failure patients have preserved EF, and their prognosis is similar to those with reduced EF 1, 2, 3.
Do not confuse the ejection murmur with valvular disease: The echocardiogram shows no valvular abnormalities. The ejection murmur likely represents turbulent flow across the LV outflow tract in the setting of LVH 1.
Do not overlook the significance of S4: An S4 gallop is a specific finding for diastolic dysfunction and elevated LV end-diastolic pressure, particularly in the context of LVH 1.