Characteristics of Pulmonary Vein Enlargement in Non-Valvular Atrial Fibrillation Patients with Stroke

PURPOSE: The association between pulmonary vein (PV) dilatation and stroke in non-valvular atrial fibrillation (AF) patients remains unknown. MATERIALS AND METHODS: We examined the left atrium (LA) and PV in control (n=138) and non-valvular AF patients without (AF group, n=138) and with non-hemorrhagic stroke (AF with stroke group, n=138) using computed tomography. RESULTS: The LA, LA appendage (LAA), and all PVs were larger in the AF than control patients. The orifice areas of the LAA (5.6+/-2.2 cm2 vs. 4.7+/-1.7 cm2, p<0.001), left superior PV (3.8+/-1.5 cm2 vs. 3.4+/-1.2 cm2, p=0.019), and inferior PV (2.3+/-1.0 cm2 vs. 1.8+/-0.7 cm2, p<0.001) were larger in the AF with stroke than in the AF only group. However, right PVs were not different between the two groups. In a multivariate analysis, the orifice areas of the left superior PV [odds ratio (OR) 1.25, 95% confidence interval (CI) 1.03-1.51, p=0.02], left inferior PV (OR 1.97, 95% CI 1.41-2.75, p<0.001), and LAA (OR 1.30, 95% CI 1.13-1.50, p<0.001) were independent predictors of stroke. CONCLUSION: Compared to the right PVs, the left PVs and LAA exhibited more significant enlargement in patients with AF and stroke than in patients with AF only. This finding suggests that the remodeling of left-sided LA structures might be related to stroke.

Análise comparativa entre a vascularização ventricular e do nó sinoatrial em gatos / Comparative analysis between ventricular and sinoatrial node vascularization in cats

A possível existência de interdependência na nutrição de territórios atriais e ventriculares tem sido objeto de preocupação por partes dos cardiologistas, especialmente no que tange a vascularização do nó sinoatrial e sua dependência apenas de uma artéria coronária ou de ambas e de sua relação com o predomínio destes vasos na vascularização ventricular. Assim, este estudo objetiva avaliar a relação da irrigação do nó sinoatrial e a origem e a predominância das artérias coronárias na vascularização dos ventrículos, para tanto utilizou-se 30 corações de gatos sem raça definida adultos, machos e fêmeas, sem sinais de afecção cardíaca. Os corações foram injetados pela aorta torácica com Neoprene Latex 450, corados com pigmento vermelho e dissecados posteriormente. Verificou-se que quando ocorria predomínio da vascularização ventricular do tipo esquerda (63,34 por cento) a irrigação do nó sinoatrial ficou predominantemente na dependência do ramo proximal atrial direito (78,9 por cento) ou com menor freqüência pelo ramo proximal atrial esquerdo (21,1 por cento). Na vascularização ventricular do tipo equilibrada (33,34 por cento), a irrigação do sinoatrial ficou na dependência mais freqüentemente do ramo proximal atrial direito (80 por cento), ou com menor freqüência a nutrição do nó se deu pelo ramo proximal atrial esquerdo (20 por cento). Em um caso isolado, ocorreu a vascularização ventricular do tipo direita (3,34 por cento), a nutrição do sinoatrial, ficou na dependência exclusiva do ramo intermédio atrial direito. Estes resultados indicam que nesta espécie não existe relação entre a irrigação do nó sinoatrial e o tipo de vascularização ventricular, independentemente do sexo.

The possible existence of interdependence in the blood nutrition of both atrial and ventricular territories has been a subject of concern to cardiologists, mainly related to vascularization of the sinoatrial node and its dependence on just one coronary artery or both, and its relation with the predominance of these vessels in the ventricular vascularization. Therefore, this research aimed evaluated the relation of blood irrigation of the sinoatrial node in relation to the coronary artery predominance in the ventricle vascularization. In doing so, we analyzed 30 hearts of cats without pedigree, males and females, adults of several ages. They were not carrying any heart problems. The hearts were injected by the thoracic aorta with Neoprene Latex 450, stained with red pigment, and then they were dissected. It was found that when there was a prevalence of ventricular vascularization of the left type (63.34 percent) the sinoatrial node irrigation was predominantly in the dependency of the Ramus proximalis atrii dextri (78.9 percent) or with less frequency by Ramus proximalis atrii sinister (21.1 percent). In the ventricular vascularization of the balanced type (33.34 percent), the pacemaker irrigation was in dependence more often of Ramus proximalis atrii dextri (80 percent) or with less frequency the nutrition of the sinoatrial node occurred by Ramus proximalis atril sinister (20 percent). In a single-case, we observed the ventricular vascularization of the right type (3.34 percent), the pacemaker nutrition was in an exclusive dependence of the Ramus intermedius atril dextri. These results suggest in this species there is no relationship between both the sinoatrial node irrigation and the type of ventricular vascularization, regardless of gender.

Effect of acute haemodilution on right atrial type-A receptor activity and right atrial pressure in anaesthetized cats.

To determine the effects of acute haemodilution on right atrial pressure and right atrial type-A receptor activity, experiments were conducted in nine anaesthetized cats. Haemodilution was induced by replacement of blood by same volume of dextran (molecular weight-150000). Arterial blood pressure, right atrial pressure and right atrial type-A receptor activity were recorded. Hematocrit, arterial blood pO2, pCO2, and pH were measured. Mean arterial blood pressure, pO2, pCO2, and pH were not altered by haemodilution which extended to a hematocrit level of about 13%. Mean right atrial pressure, 'a' wave pressure showed significant changes after 2nd and 3rd exchange. Heart rate and 'a' wave amplitude changed significantly (P < 0.05) after 3rd exchange. The amplitude of the 'a' wave was increased from 3.57 +/- 0.93 to 5.79 +/- 1.46 cm H2O, heart rate was increased from 163.89 +/- 5.36 to 169.22 +/- 4.84 beats/min, mean right atrial pressure was increased from 2.85 +/- 0.31 to 4.61 +/- 0.27 cm H2O, initial 'a' wave pressure was increased from 1.78 +/- 0.09 to 5.06 +/- 0.44 cm H2O. The data indicate that under present experimental conditions, the activity of the type-A receptor did not show any significant change (P > 0.05) on acute haemodilution. Significant increase (P < 0.05) in the amplitude of 'a' wave, mean right atrial pressure and initial 'a' wave pressure could be attributed to increased myocardial contractility.

Value of haemodynamic studies during pericardiocentesis in a cardiac catheterisation laboratory.

Pericardiocentesis was performed in 20 patients using a 7F diagnostic catheter in a cardiac catheterisation laboratory under fluoroscopic control, with haemodynamic and electrocardiographic monitoring. This technique offers several advantages over the bedside technique which utilises a sharp needle. The technique utilised for percutaneous aspiration is safe and simple and allows complete drainage of fluid. The haemodynamic monitoring before and after drainage aids in detecting cases of effusive constriction.

Electrocardiographic features of atrial depolarization during pacing of right atrial appendage.

Identification of atrial capture during pacing from right atrial appendage is frequently difficult. Electrocardiograms of forty five patients implanted with AAI/DDD pacemakers (thirty unipolar, fifteen bipolar) were analysed to characterize the specific morphology of paced P waves. Compared to sinus P waves, atrial pacing resulted in atrial depolarization of lower amplitude (0.16 +/- 0.05 mv vs 0.11 +/- 0.032 mv, P less than 0.005) but increased duration (0.07 +/- 0.009 sec vs 0.08 +/- 0.017 sec, P less than 0.005). P wave morphology was similar in unipolar and bipolar pacing units. It was positive in lead I (80%), II (71.11%), III (80%) and aVF (75.55%). In lead aVL, paced P waves were usually diphasic with an initial negative deflection (35.55%). Precordial leads showed paced atrial depolarization of small amplitude and did not help in identification of atrial capture. In unipolar pacing P waves were best seen in lead III because of small pacing spike in this lead. Lead II was suitable for identification of paced P waves in bipolar pacing. Thus careful examination of standard ECG leads for paced P waves of low amplitude, prolonged duration and specific morphology can help in confirming atrial capture following pacing stimulus from right atrial appendage.