Savvas T. Toumanidis

Atrial Pressure and Experimental Atrial Fibrillation

SIDERIS, D.A., et al.: Atrial Pressure and Experimental Atrial Fibrillation. A possible profibrillatory effect on the atria of an elevated atrial pressure and the site of atrial stimulation was examined. In 15 anesthetized dogs, right or left atrial or biatrial pacing was applied at a high rate (300–600/min) for 5 seconds at double threshold intensity under a wide range of atrial pressures achieved by venous or arterial transfusion or bleeding. Induction of atrial fibrillation in 236 of 1,971 pacing runs was associated with a significantly higher (P < 0.001) atrial pressure (21.6 ± 12.2 mmHg, mean ± SD) than maintenance of sinus rhythm (16.8 ± 11.1 mmHg in 1,735 of 1,971 pacing runs). Stimulation of the right atrium resulted in atrial fibrillation more frequently than left atrial or biatrial stimulation, with biatrial stimulation less frequent than right or left atrial stimulation. The induction of atrial fibrillation was related to the atrial pressure and to the site of stimulation but not to the pacing rate or the prepacing heart rate. The prepacing heart rate, associated with failure to induce sustained atrial fibrillation, was higher than that associated with atrial fibrillation in 12 of 15 experiments (significantly in 6) and not significantly lower in 3 of 15. Atrial fibrillation lasting 1 minute or more was more frequently associated with simultaneous stimulation of both atria than of either atrium alone. Thus, an elevated atrial pressure may facilitate the induction of atrial fibrillation. The site of stimulation also plays an important role for both the induction and maintenance of atrial fibrillation in this model.

24 h blood pressure profile affects the left ventricle independently of the pressure level. A study in untreated essential hypertension diagnosed by office blood pressure readings.

This work examines whether the 24 h blood pressure (BP) pattern per se might affect the left ventricular structure independently of the pressure level. One hundred subjects with abnormally high office BP readings who had never received any antihypertensive treatment were submitted to 24 h ambulatory BP monitoring and left ventricular echocardiographic assessment. They were classified into two groups, as follows: dippers (group 1), consisting of 46 subjects whose mean nighttime systolic BP was reduced by at least 10% in comparison to the corresponding daytime value, and nondippers (group 2), consisting of 54 subjects whose nighttime BP did not drop or was reduced by < 10%. Left ventricular mass and end-diastolic volume values, both normalized for body surface area, were significantly higher in nondippers (r = 3.12, P < .003, and r = 7.46, P < .001, respectively). The two groups did not differ in diastolic thickness of either intraventricular septum or left ventricular posterior wall (both values normalized for body surface area), in mean 24 h systolic or diastolic or average blood pressure, or in age. In conclusion, in untreated essential hypertension diagnosed on the basis of abnormal office BP readings, the higher incidence of left ventricular mass increase in subjects unable to reduce their blood pressure during the night was more due to left ventricular dilatation than to myocardial wall thickening. The effect of the 24 h BP profile on left ventricular volume appears to be independent of both the BP level and age.

A self-learning approach to history-taking.

Summary. The present study examines the effectiveness of self‐learning in interviewing skills training. Self‐learning was carried out by self‐evaluation of ones interviews by the use of an audiotape. Fifteen doctors specializing in internal medicine listened to their interviews and evaluated themselves against the suggested performance included in a rating scale. This procedure was repeated twice and composed the educational programme. Three main aspects of history‐taking were involved: (1) eliciting patient information; (2) interviewing technique and (3) attitudes toward the patient. Comparison of performance at the first and third interview revealed significant improvement in all three aspects. Doctor‐patient communication and written history performance were involved indirectly in the study but no significant improvement was revealed. The educational approach appeared simple and effective to the doctors. It is suggested that a brief programme of self‐learning with feedback from audiotapes is both convenient and effective, improving essential aspects of history‐taking performance.

Ability of Ambulatory Blood Pressure Monitoring and Myocardial/Carotid Ultrasound to Predict the Location and the Severity of Coronary Artery Lesions in Normotensive Patients: A Clinical Study

Pulse pressure has been recognized as a marker of cardiovascular disease in normotensives. Moreover, internal carotid artery intima-media thickness (IMT) has been proposed to reflect coronary artery lesions. The aim of the present study was to evaluate the predictive value of other parameters derived from ambulatory blood pressure monitoring (ABPM), myocardial ultrasound, and carotid ultrasound to predict the location and the severity of coronary artery disease in normotensives. One hundred and thirteen patients with suspected coronary artery disease underwent coronary angiography, 24-h ABPM and myocardial/carotid ultrasound. Multivariate analysis was applied and equations were extrapolated based on independent variables derived from ABPM and ultrasound. The Gensini score was independently correlated with male gender, pulse pressure, average heart rate for both 24-h (p=0.001) and night (p=0.006) values, as well as percentage of high systolic blood pressure (BP), average diastolic BP, average mean BP, and heart rate concerning daily mesurements (p=0.001). Moreover, the Gensini score was independently correlated with end-systolic volume, posterior wall thickness during systole and intraventricular septum thickness during diastole, along with male gender and age (p=0.001), as well as mean internal and right common carotid artery IMT (p=0.002). Similar mathematical formulas have been calculated separately for the coronary arteries and their main branches. In conclusion, the location and the severity of coronary disease can be effectively evaluated by ABPM and myocardial/carotid ultrasound in normotensives. This approach could be useful for determining atypical patients at risk and/or for treating patients with suspected coronary disease who refuse coronary angiography.

Effect of Acute Ventricular Pressure Changes on QRS Duration

The effect of acute changes in ventricular pressure is examined on the QRS duration to clarify the mechanism of ventricular pressure-related arrhythmogenesis. Ventricular pressure was changed acutely by arterial transfusion-bleeding into an open-air ventricular pressure reservoir that was either off or on a metaraminol intravenous drip. While maintaining ventricular pressure at several levels, the QRS duration was measured at 200 mm/s paper speed. The QRS duration correlated significantly with the left ventricular pressure in all 14 dogs examined. An average change in ventricular by 100 mmHg was associated with a change of about 18% in the QRS duration. An acute ventricular pressure elevation impairs the ventricular conduction, which may contribute to ventricular pressure-related arrhythmogenicity.

Anatomical origin of pressure-related ventricular ectopic rhythms

In order to determine the origin of pressure-related ectopic rhythms, the main arteries were clamped in 11 anesthetized dogs, or the arteries or veins were transfused, while on or off metaraminol. The epicardial right atrial electrogram, the intracavity electrograms and the pressure of the two ventricles were recorded. Sinus rhythm was associated with 64/64 (100%) of the control periods off metaraminol, but only 19/50 (38%) of the clamping of the main arteries (P << 0.0005). In 14/27 aortic clampings ectopic beats appeared from the left ventricle and in 13/27 from the right one. In 4/23 clampings of the pulmonary artery ectopic beats appeared from the left ventricle and in 15/23 from the right one (P < 0.05). Sinus rhythm was associated with significantly lower left ventricular systolic pressure than any ventricular arrhythmia. The left ventricular systolic pressure associated with ectopic rhythms from the left ventricle was significantly (P < 0.005) higher than that associated with those from the right ventricle. The right ventricular systolic pressure during sinus rhythm was significantly (P < 0.005) lower than that during ectopic rhythm from any ventricle. It is concluded that a rise in the pressure of one ventricle tends to cause ventricular ectopic rhythms originating predominantly, but not exclusively, from this ventricle. The origin of ventricular ectopic rhythms from the right ventricle does not preclude that the arrhythmia may respond favorably to lowering of the systemic pressure.