Can Hypertension (HTN) cause cardiomyopathy?

Hypertension and Cardiomyopathy: Pathophysiological Connection

Yes, hypertension can cause cardiomyopathy through sustained pressure overload leading to pathological cardiac remodeling and eventual heart failure. 1

Pathophysiological Mechanism

Hypertension leads to cardiomyopathy through a progressive sequence of cardiac adaptations:

1. Initial Adaptive Response:

   • Concentric left ventricular hypertrophy (LVH) develops as an adaptive mechanism to normalize systolic wall stress in response to pressure overload 1, 2
   • This compensatory hypertrophy initially preserves cardiac function

2. Transition to Pathological Remodeling:

   • Sustained pressure overload causes structural modifications in cardiac muscle:
     • Alterations in gene expression
     • Loss of cardiomyocytes
     • Defective vascular development
     • Progressive myocardial fibrosis 1, 2

3. Progression to Heart Failure:

   • Diastolic dysfunction develops first, often with preserved ejection fraction (HFpEF)
   • With continued pressure overload, the compensatory response may transition to systolic dysfunction
   • End-stage hypertensive heart disease results in dilated cardiomyopathy with both diastolic dysfunction and reduced ejection fraction 1, 2

Clinical Manifestations of Hypertensive Cardiomyopathy

Hypertensive cardiomyopathy presents with distinct features:

• Left Ventricular Hypertrophy: Most patients with hypertensive LVH have maximal interventricular septal thickness <15mm (in Caucasians) or <20mm (in Black patients) 1
• ECG Changes: LVH by voltage criteria is seen in 10-20% of hypertensive patients with LVH, but marked repolarization abnormalities are unusual 1
• Arrhythmias: Both supraventricular and ventricular arrhythmias may occur, with atrial fibrillation being most common 1
• Progression Pattern: The "classic paradigm" involves concentric LVH that eventually progresses to chamber dilation and systolic dysfunction in what is described as a "burned out" left ventricle 1

Prognostic Implications

LVH from hypertension carries significant prognostic implications:

• LVH is considered evidence of target organ damage in hypertension 1
• For every 50 g/m² higher left ventricular mass index, there is a 1.73-fold increased risk of death, independent of blood pressure level 1
• In the MAVI study of patients with uncomplicated essential hypertension, there was a 40% higher risk of cardiovascular events for each 39 g/m² greater left ventricular mass index 1
• Hypertensive dilated cardiomyopathy has a 5-year mortality rate of approximately 26% 3

Differentiating Hypertensive Cardiomyopathy from Hypertrophic Cardiomyopathy

Key features favoring hypertensive heart disease over hypertrophic cardiomyopathy include:

• Normal ECG or isolated increased voltage without repolarization abnormality
• Regression of LVH over 6-12 months with tight systolic blood pressure control (<130 mm Hg)
• Absence of right ventricular hypertrophy
• Absence of late gadolinium enhancement at RV insertion points on CMR 1

Management Implications

Effective blood pressure control is crucial to prevent progression and potentially reverse hypertensive cardiomyopathy:

• Antihypertensive therapy can reduce left ventricular mass by 5-13% depending on drug class 1
• ACE inhibitors appear most effective (13.3% reduction in LV mass), followed by calcium channel blockers (9.3%), diuretics (6.8%), and beta-blockers (5.5%) 1
• Long-acting thiazide-like diuretics (chlorthalidone and indapamide) may have advantages over other antihypertensive drugs in preventing heart failure 2
• Target blood pressure should be <130/80 mmHg, but caution is advised in patients with wide pulse pressures to avoid very low diastolic pressures (<60 mmHg) 1

Clinical Pearls and Pitfalls

• Pitfall: "Decapitated hypertension" refers to the decrease in blood pressure resulting from reduced pump function in heart failure, which may mask the underlying hypertensive etiology 2
• Pitfall: Low-dose, once-daily hydrochlorothiazide should be avoided in patients with hypertensive cardiomyopathy 2
• Pearl: In patients with hypertensive cardiomyopathy, independent predictors of mortality include advanced age, lower body mass index, and severity of left ventricular systolic dysfunction 3