Analysis of electrocardiographic signs in hypertrophic cardiomyopathy before and after septal myectomy. New criterion for proximal left bundle branch block

Aim. To analyze 20 electrocardiographic (ECG) signs of left bundle branch block (LBBB) before and after septal myectomy in patients with hypertrophic cardio myopathy (HCM) and develop a criterion for proximal LBBB based on the selected signs.Material and methods. This retrospective non-randomized study included 50 patients with obstructive HCM who underwent septal myectomy. There were following inclusion criteria: QRS width <120 ms before surgery, transaortic access during septal myectomy, and QRS width ≥120 ms in the early postoperative period. For each patient, ECGs were analyzed before septal myectomy and in the first week after surgery. At the same time, 20 ECG signs proposed earlier in the LBBB criteria were independently assessed.Results. Exsection of a small myocardial area of the basal interventricular septal parts, weighing an average of 4,9±2 grams, led to a significant increase in the QRS width (by 61±14,6 ms) and the prevalence of almost all ECG signs of LBBB. In 100% of cases (n=50), the following signs demonstrated significant dynamics after surgery: (1) midQRS notching or slurring in ≥2 contiguous leads (I, aVL, V1-V2, V5-V6); (2) absence of q wave in V5-V6 and (3) discordant T wave in at least two leads (I, aVL, V5, V6). Based on the design of the study, (4) QRS width ≥120 ms was additionally included. These ECG characteristics were combined into a new criterion for proximal LBBBConclusion. A new criterion for proximal LBBB was developed using the pathophysiological model of iatrogenic conduction block of left bundle branch. Further estimation of this criterion on a set of candidates for CRT with heterogeneous level of LBBB is necessary

Morphological study of telocytes in the left atrium in patients with long-term persistent atrial fibrillation

The telocytes were found in the human atria in 2005. Atrial fibrillation (AF) is the most common heart rhythm disorder, accompanied by inflammation and fibrosis, however, the morphological analysis of telocytes in this pathology has not yet been performed.Aim. To make morphological analysis of left atrial telocytes in patients with longterm persistent AF.Material and methods. The study was based on the left atrial (LA) wall of 10 patients with AF, 10 without AF (autopsy material) and LP fragments of 2 patients with AF (surgical material). A histological, immunohistochemical, and ultrastructural study, telocyte culture isolation, and confocal laser microscopy were performed.Results. The presence of telocytes in the LA was confirmed. Morphometric analysis revealed that the average number of telocytes in the LP was significantly less by 3 times in patients with AF than without it (2,7±1,1 vs 8,2±3,0 with x400). Correlation analysis revealed significant negative associations of the number of telocytes with AF, fibrosis, lipomatosis, and inflammation.Conclusion. The development of inflammation and fibrosis in AF is accompanied by the loss of telocytes

The way to control the interventricular septum thickness during septal myectomy. An experimental study

Background: At present, there are no methods for intraoperative monitoring of the interventricular septum (IVS) thickness in a stopped and empty heart. This might be an obvious reason for unsatisfactory results after a number of septal myectomies.Aim: To provide an experimental background for the method to control the IVS thickness (that we had proposed) during septal myectomy.Materials and methods: The proposed technique is based on the transillumination method. The experimental models were cadaveric porcine hearts, as well as fragments of the human myocardium removed during septal myectomies. The thickness of the translucent myocardium was estimated depending on the local illumination value at the entrance to the myocardium and the external illumination of the surgical field. We compared the results of 67 septal myectomies performed in the clinic of the Almazov National Medical Research Centre with the results of 35 similar experimental procedures with cadaveric porcine hearts using the proposed way of measurement.Results: A graph of the illumination at the entrance to the myocardium against the thickness of the translucent myocardium was constructed. After conventionally performed septal myectomies the median variation of the myocardial thickness was 4 [3; 6] mm. In the experiment using the proposed control method, the median variation was 1 [1; 2] mm, i.e. significantly less than with the conventional approach (p = 3 x 10-10).Conclusion: The method to control the IVS thickness when performing septal myectomy makes it possible to achieve the required myocardial thickness the resection area with much greater accuracy than with the conventional one