thallium-201 and Cardiomyopathy--Hypertrophic

Hypertrophic cardiomyopathy (HCM) is an often under-diagnosed cause of left ventricular hypertrophy (LVH). It affects 1/500 of the population, is the most commonly inherited cardiovascular disorder, and can present in apical, concentric, or septal forms. Although most patients are asymptomatic, sudden cardiac death can be the initial presentation of HCM. By retrospectively enrolling patients suspected of having three different types of HCM in the absence of epicardial coronary stenosis, we aimed to examine systolic and diastolic dysfunction and perfusion abnormalities using both Doppler echocardiography and state-of-the-art gated single-photon emission computerized tomography (SPECT) myocardial perfusion imaging (MPI) with a cadmium-zinc-telluride camera and thallium-201. Both regional perfusion and gated SPECT parameters were collected in addition to diastolic parameters from Doppler echocardiography. The results showed that mild ischemia was common in patients suspected of having HCM, with a mean summed stress score of 4.7 ± 4.9 (score 0-4 in 17-segment model). The patients with HCM were associated with discernible left ventricular mechanical dyssynchrony, especially those with the apical form. In addition, diastolic dysfunction was prevalent and early to late ventricular filling velocity ratios were significantly different between groups. By combining gated-MPI and Doppler data, the trivial functional changes in HCM may be identified.

Topics: Aged; Cardiomyopathy, Hypertrophic; Correlation of Data; Echocardiography, Doppler; Female; Humans; Hypertrophy, Left Ventricular; Male; Middle Aged; Myocardial Perfusion Imaging; Pilot Projects; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

This study aimed to evaluate the changes in left ventricular remodelling with time in patients with hypertrophic cardiomyopathy (HCM) using thallium-201 myocardial scintigraphy.. Forty-eight patients with HCM participated in the study. The extent score (ES) and a newly devised index termed the 'mean count change' (MCC) were used to evaluate the myocardial perfusion defects. Using the amount of thallium-201 uptake (TU), MCC (%) was calculated using the following formula: (last TU - initial TU)∕initial TU × 100. To confirm the site of the lesion, the left ventricle was divided into five segments: anterior, septal, inferior, lateral, and apex. Cardiovascular complications and deaths were recorded. The mean follow-up period was 8.6 ± 2.0 years. ES increased from 17.4 ± 13.7% to 44.0 ± 22.3% (P < 0.0001). MCC increased from 0% to 12.0 ± 9.0% (P < 0.0001). The apex was the most frequent site of lesion. Twenty-seven patients (56.3%) had experienced left ventricular heart failure (LVHF). Both ES and MCC were greater in patients with LVHF than in those without LVHF. An overlap between the two groups was greater in ES than in MCC. Patients with LVHF had a higher incidence of atrial fibrillation and apoplexy. Nineteen patients (39.6%) died during the study period; 14 died from LVHF, 3 from sudden cardiac death, and 2 from cancer.. Thallium-201 myocardial scintigraphy is useful for detecting the severity of myocardial damage and for confirming the lesion site in patients with HCM. MCC may be superior to ES in the evaluation of these changes with time.

Topics: Cardiomyopathy, Hypertrophic; Heart; Humans; Myocardial Perfusion Imaging; Thallium Radioisotopes