Estratificação de risco para morte súbita na cardiomiopatia hipertrófica: bases genéticas e clínicas

O diagnóstico da obstrução da via de saída do ventrículo esquerdo na cardiomiopatia hipertrófica

“…Physical exercise produces increase of contractility and heart rate, effects which, along with the decrease of peripheral vascular resistance, trigger or determine worsening of obstruction and increase in LV filling pressure 26,27 . Syncope or presyncope may be the consequence of arrhythmias or autonomic disorder [28][29][30] , but would derive from outflow tract obstruction when related to larger exertion or to swiftly assuming standing position 31 .…”

Avaliação diagnóstica da cardiomiopatia hipertrófica em fase clínica e pré-clínica

“…The annual incidence of HCM is approximately 1% in adults 18 and 4% in children 19 . Cellular disarray and reparative fibrosis, together with LV outflow tract obstruction, microcirculatory disease, and physical exercise, produce electrophysiological instability and favor the genesis of fatal arrhythmias, either as a primary disorder or secondary to myocardial ischemia 2,14,20 . In young people and in cardiac troponin T gene mutations, with greater predisposition to premature sudden death, cell disarray and myocardial ischemia are regarded as determinants in the development of fatal arrhythmias 10 .…”

“…Although some relationship has been demonstrated between inducibility and prognosis, its predictive accuracy is debatable 2,14,20 . It may be helpful in patients with unexplained syncope 2 .…”

“…It may be helpful in patients with unexplained syncope 2 . High resolution ECG has low predictive accuracy as well 20 . T-wave alternans is regarded as predictive of ventricular arrhythmias and sudden death.…”

“…More recent studies provided new data on HCM clinical and genetic profile, revealing less specific phenotypes and lower prevalence of malignant mutations 31,70,71 . For the purpose of prognostic evaluation, it is necessary to expand the analysis of genotype-phenotype relationships, including larger, unrelated families with a higher number of affected members 7,20 . As molecular genetic diagnosis is expensive and timeconsuming, it has been limited to research centers.…”