Left ventricular rotational mechanics in patients with coronary artery disease: differences in subendocardial and subepicardial layers. Issue 21 (18th October 2010) - Bertini, Matteo
Abstract : Objective: Subendocardial and subepicardial layers have opposite orientation of the myofibres and they are differently affected by coronary artery disease. This study investigated the differences in subendocardial and subepicardial left ventricular (LV) twist in patients with coronary artery disease. Methods: 214 patients were included in the study: 60 with first ST elevation myocardial infarction (STEMI), 111 with chronic ischaemic heart failure (HF) and 43 normal subjects. Real-time three-dimensional echocardiography provided LV volumes and function. Two-dimensional speckle tracking echocardiography differentiating the subendocardial and subepicardial layers was used for the assessment of LV twist. Patients with STEMI were divided into two groups (small and large STEMI). Results: Compared with normal subjects, peak subendocardial LV twist was significantly impaired in patients with STEMI (11.2±6.0° vs 15.3±2.7°, p<0.001). In patients with chronic HF, peak subendocardial LV twist was even more impaired (4.6±3.4°, p<0.001 vs normal subjects and patients with STEMI). Conversely, peak subepicardial LV twist was not statistically different between normal subjects and patients with STEMI (8.9±1.9° vs 8.4±4.4°, p=0.98), whereas it was significantly impaired in patients with chronic HF (2.6±2.5°, p<0.001 vs normal subjects and patients with STEMI). Peak subendocardial LV twist was not statistically different between large and small STEMI, whereas peak subepicardial LV twist was significantly lower in large STEMI than in small STEMI (7.1±4.8° vs 9.6±3.6°, p=0.025). Conclusions: Subendocardial LV twist is reduced in patients with STEMI and chronic ischaemic HF whereas subepicardial LV twist is reduced only in chronic ischaemic HF. When STEMI are divided into large and small infarctions, it becomes evident that subepicardial LV twist is only reduced in large infarctions.