Light and electron microscopic features of surgically excised left atrial appendage in rheumatic heart disease patients with atrial fibrillation and sinus rhythm

IntroductionThere are few studies comparing the pathology of the remodeled substrate in patients of rheumatic heart disease with atrial fibrillation (AF) and normal sinus rhythm (NSR).MethodsThe study group comprised 30 patients with rheumatic heart disease undergoing mitral valve replacement. Excised left atrial appendages of these patients [17 with persistent AF and 13 NSR (control group)] were subjected to light and electron microscopic examination.ResultsThe histopathological findings of the myocardium were characterized by cardiomyocyte hypertrophy (CH), nuclear enlargement (NE), perinuclear clearing (PC), sarcoplasmic vacuolation (SV), fibrosis, and inflammation in the patients with AF and NSR. NE (17/17 vs. 4/13; P= .004), PC (17/17 vs. 4/13; P= .004), SV (17/17 vs. 9/13; P= .06), and fibrosis (15/17 vs. 3/13; P= .001) were all significantly more common in patients with AF. Inflammatory cells were observed in 9/17 patients of AF as compared to 1 in NSR patients (9/17 vs. 1/13; P= .02). CH was common in the patients with AF as compared with those in NSR (17/17 vs. 10/13; P= .103).In AF patients, electron microscopy revealed cardiomyocytes with depletion of the contractile elements (Z-bands), glycogen particle accumulation, and an increase in mitochondria. Cells severely affected by AF showed loss of contractile elements with extensive areas of SV, presence of myelin figures, and mitochondrial aggregates. Majority of AF cases showed extensive fibrosis in the form of collagen bundles in the interstitium.ConclusionThe left atrial substrate in AF as compared with NSR, in rheumatic heart disease patients, is associated with significant degenerative remodeling and ongoing inflammation that is associated with extensive fibrosis.     

Periodic respiration in patients with heart failure

Summary Patients with heart failure are known to demonstrate periodic respiration (PR) during sleep. The factors causing PR are not well known. We therefore studied 20 patients (aged 18–66 years) with idiopathic dilated cardiomyopathy. Full-night polysomnography and evaluation of respiration and transcutaneous oxygen saturation were performed. Hypercapnic ventilatory response (HCVR) was evaluated during daytime. The patients showed PR for 25 ± 26% (mean ± standard deviation) of total sleep time. During PR, oxygen desaturated 7.1±4.6%. Sleep was impaired. HCVR was normal. Oxygen desaturation during PR was predicted by HCVR (r=0.47, P<0.05) and left atrial diameter (r=0.60, P<0.05). The time period of PR expressed as a fraction of total sleep time was correlated with HCVR (r=0.45, P<0.05) and left atrial diameter (r=0.51, P<0.05). In conclusion, PR with oxygen desaturation, arousals, and impaired sleep was observed in stable heart failure. HCVR and left heart dimensions were related to PR. These findings confirm the concept of a feedback loop describing respiratory control in PR.Abbreviations PR periodic respiration - HCVR hypercapnic ventilatory response - LA left atrial diameter - LVED left ventricular end-diastolic diameter - REM rapid eye movement     

Significance of statistical characteristics of the sinus rhythm of the heart

A statistical analysis was made of long continuous records of RB intervals of the ECG of 64 patients with pyogenic surgical infections. The following indices were examined: the mean RR interval , standard deviation (), range of variation (V), first and third correlation coefficients, excess, asymmetry, ratio, and the form of the autoregression cluster. In three groups of patients differing in the severity of their condition, the values of , , and V were found to differ statistically significantly. These differences were clearly reflected in the size and shape of the autoregression cluster. The results suggest that the statistical chracteristics of long records of the cardiac rhythm can be used for the objective assessment of the severity of the patient's condition and the efficacy of his treatment.A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR M. I. Kuzin). Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 84, No. 11, pp. 628–630, November, 1977.