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Toronto Notes 2019 Myocardial Disease
• non-obstructiveHCM:noLVOTobstruction
• manypatientshavediastolicdysfunction(impairedventricularfillingsecondarytoLVhypertrophy
which decreases compliance)
Signs and Symptoms
• clinicalmanifestations:asymptomatic(common,thereforescreeningisimportant),SOBonexertion, angina, presyncope/syncope (due to LV outflow obstruction or arrhythmia), CHF, arrhythmias, SCD
• pulses:rapidupstroke,“spikeanddome”patternincarotidpulse(inHCMwithoutflowtractobstruction)
• precordialpalpation:PMIlocalized,sustained,doubleimpulse,‘tripleripple’(tripleapicalimpulsein
HOCM), LV lift
• precordialauscultation:normalorparadoxicallysplitS2,S4,harshsystolicdiamond-shapedmurmurat
LLSB or apex, enhanced by squat to standing or Valsalva (murmur secondary to LVOT obstruction as compared to AS); often with pansystolic murmur due to mitral regurgitation
Investigations
• ECG/Holtermonitor:LVH,highvoltagesacrossprecordium,prominentQwaves(leadI,aVL,V5,V6), tall R wave in V1, P wave abnormalities
• transthoracicechocardiographyandecho-Dopplerstudy:asymmetricseptalhypertrophy(lesscommonly apical), systolic anterior motion (SAM) of mitral valve and MR; LVOT gradient can be estimated by Doppler measurement
• geneticstudies(±magneticresonanceimaging)canbehelpfulwhenechocardiographyisinconclusive for diagnosis
• cardiaccatheterization(onlywhenpatientbeingconsideredforinvasivetherapy)
Management
• avoidfactorswhichincreaseobstruction(e.g.volumedepletion) ■ avoidance of all competitive sports
• treatmentofobstructiveHCM
■ medical agents: β-blockers, disopyramide, verapamil (started only in monitored setting),
phenylephrine (in setting of cardiogenic shock)
■ avoid nitrates, diuretics, and ACEI as they increase LVOT gradient and worsen symptoms
• patientswithobstructiveHCManddrug-refractorysymptoms
■ surgical myectomy
■ alcohol septal ablation - percutaneous intervention that ablates the hypertrophic septum with 100%
ethanol via the septal artery
■ dual chamber pacing (rarely done)
• treatmentofpatientsathighriskofsuddendeath:ICD
• first-degreerelatives(children,siblings,parents)ofpatientswithHCMshouldbescreened(physical,
ECG, 2D echo) every 12-18 mo during adolescence, then serially every 5 yr during adulthood
Prognosis
• potentialcomplications:AFib,VT,CHF,suddencardiacdeath(1%risk/yr;mostcommoncauseofSCD in young athletes)
■ major risk factors for sudden death (consider ICD placement)
■ history of survived cardiac arrest/sustained VT
■ family history of multiple premature sudden deaths
■ other factors associated with increased risk of sudden cardiac death
◆ syncope (presumed to be arrhythmic in origin)
◆ non-sustained VT on ambulatory monitoring
◆ marked ventricular hypertrophy (maximum wall thickness ≥30 mm)
◆ abnormal BP in response to exercise (in patients <40 yr old with HCM)
Restrictive Cardiomyopathy
Definition
• impairedventricularfillingwithpreservedsystolicfunctioninanon-dilated,non-hypertrophied ventricle secondary to factors that decrease myocardial compliance (fibrosis and/or infiltration)
Etiology
• infiltrative: amyloidosis, sarcoidosis
• non-infiltrative:scleroderma,idiopathicmyocardialfibrosis
• storagediseases:hemochromatosis,Fabry’sdisease,Gaucher’sdisease,glycogenstoragediseases • endomyocardial
■ endomyocardial fibrosis, Loeffler’s endocarditis, or eosinophilic endomyocardial disease
■ radiation heart disease
■ carcinoid syndrome (may have associated tricuspid valve or pulmonary valve dysfunction)
Clinical Manifestations
• CHF(usuallywithpreservedLVsystolicfunction),arrhythmias • elevatedJVPwithprominentxandydescents,Kussmaul’ssign • S3,S4,MR,TR
• thromboembolicevents
Cardiology and Cardiac Surgery C41
RCM vs. Constrictive Pericarditis (CP)
Present similarly but CP is treatable with surgery
Key Investigations
• Echo: may show respiratory variation in blood flow in CP
• CT: may show very thickened pericardium and calcification in CP
• MRI: best modality to directly visualize pericardium and myocardium