Fig. 11.16 Hypertensiveheartdisease.(A)Systemic(left-sided)hypertensiveheartdisease.Thereismarkedconcentricthickeningoftheleftventricularwallcausingreductioninlumensize.Theleftventricleandleftatriumareshownontheright inthisfour-chamberviewoftheheart.Apacemakerispresentincidentallyintherightventricle(arrow).Notealsotheleftatrialdilation(asterisk) duetostiffeningoftheleftventricleandimpaireddiastolicrelaxation,leadingtoatrialvolumeoverload.(B)Chroniccorpulmonale.Therightventricle(shown on the left) ismarkedlydilatedandhypertrophiedwithathickenedfreewallandhypertrophiedtrabeculae.Theshapeandvolumeoftheleftventriclehavebeendistortedbytheenlargedrightventricle.
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Compensated HHD typically is asymptomatic and is suspected only from discovery of elevated blood pressure on routine physical examination, or from ECG or echocardiographic findings of left ventricular hypertrophy. In some patients, the disease comes to attention with the onset of atrial fibrillation (secondary to left atrial enlargement) and/or CHF. The mechanisms by which hypertension leads to heart failure are incompletely understood; presumably the hypertrophic myocytes fail to contract efficiently, possibly due to structural abnormalities in newly assembled sarcomeres and because the vascular supply is inadequate to meet the demands of the increased muscle mass. Depending on the severity and duration of the condition, the underlying cause of hypertension, and the adequacy of therapeutic control, patients can (1) enjoy normal longevity and die of unrelated causes, (2) develop IHD owing to the effects of hypertension in potentiating coronary atherosclerosis, (3) suffer renal damage or cerebrovascular stroke, or (4) experience congestive heart failure. The risk for SCD also is increased. Effective hypertension control can prevent or lead to the regression of cardiac hypertrophy and its attendant risks.
Cor pulmonale consists of right ventricular hypertrophy and dilation—frequently accompanied by right-sided heart failure—caused by pulmonary hypertension attributable to primary disorders of the lung parenchyma or pulmonary vasculature (
Table 11.3 ). Right ventricular dilation and hypertrophy caused by left ventricular failure (or by congenital heart disease) is substantially more common but is excluded by this definition.
Cor pulmonale can be acute in onset, as with pulmonary embolism, or can have a slow and insidious onset when due to prolonged pressure overload in the setting of chronic lung and pulmonary vascular disease (see
Table 11.3
MORPHOLOGYInacute cor pulmonale, therightventricleusuallyshowsonlydilation;ifanembolismcausessuddendeath,theheartmayevenbeofnormalsize.Chronic cor pulmonale ischaracterizedbyrightventricular(andoftenrightatrial)hypertrophy.Inextremecases,thethicknessoftherightventricularwallmaybecomparabletoorevenexceedthatoftheleftventricle(
Fig.11.16B ).Whenventricularfailuredevelops,therightventricleandatriumoftenaredilated.Becausechroniccorpulmonaleoccursinthesettingofpulmonaryhypertension,thepulmonaryarteriesoftencontainatheromatousplaquesandotherlesions,reflectinglongstandingpressureelevations.
Valvular disease may result in stenosis, insufficiency (regurgitation or incompetence), or both.
• Stenosis is the failure of a valve to open completely, obstructing forward flow. Valvular stenosis is almost
Table 11.3 Disorders Predisposing to Cor Pulmonale
Extensivepulmonaryarteritis(e.g.,Granulomatosiswithpolyangiitis)