Painful and painless myocardial ischemia detected by elevated level of high-sensitive troponin in patients with hypertrophic cardiomyopathy

Introduction

High-sensitivity troponin I (hs-TnI), an extra-precise biomarker for the detection of even small myocardial injury caused by ischemia, has been successfully used in patients with hypertrophic cardiomyopathy (HCM) [1, 2]. In the most recent studies [3, 4], measurements of hs-TnI levels were synchronized with a noninvasive assessment of hemodynamic parameters in the following way: first, resting echocardiography (including a provocative maneuver to induce a left ventricular outflow tract (LVOT) gradient) was performed, followed by ambulatory electrocardiography (ECG) Holter monitoring with devices which allow potential episodes of angina pectoris to be marked by the patients. After the 24-hour ECG Holter monitoring in conditions of typical everyday physical activity, the measurement of hs-TnI level was immediately performed. Interestingly, the biomarker level had a close time relationship with findings on Holter monitoring [3] and echocardiography [4].
High-sensitivity troponin I levels were associated with both an increased heart rate during Holter monitoring [3] and a provoked LVOT gradient [4] (stimuli provoking myocardial ischemia). These findings are corroborated by previous studies in invasive and nonphysiological, atrial pacing stressors [5–7].
From the technical point of view, in patients with HCM, verification of angina pectoris by resting or exercise ECG is practically impossible because of common abnormalities visible on resting ECG (with ischemic-like changes or significant deformation of the QT complex).

Aim

Nowadays, hs-Tn level measurement seems to be ideal for precise verification of myocardial injury due to the occurrence of ischemia in patients with HCM. The aim of this study was to collect information about episodes of angina pectoris occurring in the 24-hour period preceding the hs-TnI level measurement, both in outpatients from a clinic and patients hospitalized due to cardiac signs and symptoms.

Material and methods

A group of 100 consecutive patients with HCM, both from ambulatory care and admitted to the clinic due to cardiac signs and symptoms (pooled group), were recruited to the study. Patients from our previous ambulatory studies were included in the current study; however, the present investigation is different from the previous one [3, 4] and is based on the history of angina pectoris within 24 h before the hs-TnI measurement. We attempted to investigate a full spectrum...


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