The effects of simulated akinetic and dyskinetic aneurysms on left ventricular systolic function: clinical implications.

OBJECTIVE: Scant attention has been directed towards quantifying the degree of mechanical disadvantage produced by akinetic and dyskinetic aneurysms. The purpose of this study was to evaluate the mechanical disadvantages of simulated akinetic and dyskinetic aneurysms on left ventricular function. METHODS: An elaborate experimental apparatus consisting of a computer-controlled water pressure chamber in which is suspended a model rubber ventricle was developed. The system has been shown to reproduce accurately the ventricular and aortic pressures found in vivo. In this study, a procedure was designed to simulate akinetic and dyskinetic aneurysms of various sizes on ventricular function. RESULTS: The results indicated that an akinetic aneurysm produces little or no mechanical disadvantage with respect to ventricular pressure since systolic paradox is minimal. However, a dyskinetic aneurysm, irrespective of size, will usually compromise ventricular function due to paradoxical systolic expansion in the bulging aneurysmic sac. In vivo, other factors, such as blood coagulation and rhythm disturbances, may influence these results. CONCLUSIONS: An akinetic aneurysm causes little or no mechanical disadvantage while the dyskinetic aneurysm, irrespective of size. will restrict ventricular function. The experimental simulation system, notwithstanding its limitations, thus provides a unique procedure to quantify akinetic and dyskinetic aneurysms.

[Four-week training of patients with large anterior wall infarct: comparison with a randomized untrained control group]. / Vierwöchiges Training bei Patienten mit grossem Vorderwandinfarkt: Vergleich zu einer randomisierten nichttrainierenden Kontrollgruppe.

Thirty-nine male patients (average age 50.8 years +/- 8.4 years) with a large anterior myocardial infarction (average 45.6 days +/- 10.5 days ago) and with moderate to severe left-ventricular dysfunction (RNVA EF less than 50%) participated in the study. The patients were randomly assigned to either a training group or to a control group. They were also subdivided into training/control groups (EF less than 30% and EF = 30-50%). The training program consisted of three to four sessions per day, 5 days a week, at an intensity of up to 1 W/kg body wt. (approximately 4-5 METS). The following evaluations were recorded prior to and following the 4-week training program: relative heart volume (x-ray), echocardiographic data (enddiastolic diameter, ES-distance, and shortening fraction), and exercise stress test (work capacity, heart rate). Filling pressures, cardiac outpout, and stroke volume index were calculated from right-heart catheterization (Swan-Ganz) at rest and during exercise. Results indicate that there were no significant changes in relative heart volume, end-diastolic volume, ES-distance, resting heart rate, PCP at rest, and ejection fraction during exercise as a result of the training program. Shortening fraction showed a tendency to improve (not significant). Work capacity increased by 15 W (p less than 0.05) in the training group and by 28 W (1.5 METS, p less than 0.05) in the EF less than 30% training-group as compared with the control group. Cardiac output at rest decreased by 10% (p less than 0.05). Stroke-volume index increased in the EF greater than 30% training-group, while heart rate was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

[Technical and methodologic aspects of ambulatory long-term blood pressure monitoring systems]. / Technische und methodische Aspekte der tragbaren Blutdruck-Langzeit-Messsysteme.

The development of noninvasive, portable blood pressure measuring units began in 1962 with semi-automatic devices and cassette recorders, followed by the first automatic unit in 1968 and the introduction of digital storage system in 1978. Systems in common use today consist of a portable, battery-driven blood pressure monitor and a print-out unit. In the following, the System 5200 from SpaceLabs, which has been in use for three years in our clinic, will be described. TECHNICAL ASPECTS: In a monitor unit, amplication and filtering of analogue data measured and differentiation between signal and noise is carried out. An A/D converter digitalizes the analogue data. An integrated microprocessor analyses measured data, regulates inflation and deflation of the cuff pressure, out-put of measured and calculated values on an LCD display and storage of data. Data from 200 measurements is stored in a 2K byte RAM CMOS system. A personal computer serves for programming the monitor and evaluation of the stored data. Blood pressure measurement is carried out auscultatory with a microphone or oscillometrically if Korotkoff sounds are not detected. If the signal is disturbed, measurement is repeated within two minutes. Blood pressure measurements are performed at freely-programmable intervals from six to 60 minutes; varying time intervals can also be chosen. AUSCULTATORY BLOOD PRESSURE MEASUREMENT: A miniature pump integrated in the monitor inflates the cuff within a few seconds to a pressure of 160 mmHg or, on subsequent measurements, to 25 mmHg above the last recorded systolic value. On registration of Korotkoff sounds, the cuff pressure is increased in steps of 25 mmHg until the sounds disappear and then deflated in steps of 3 to 5 mmHg. On detection of the first Korotkoff sound, the instantaneous cuff pressure (which is converted to an electric signal by a transducer) is stored as the systolic value. Further deflation then occurs rapidly to 90 mmHg or 10 mmHg above the last measured diastolic value. With higher diastolic values, again, there is an increase in cuff pressure in steps of 25 mmHg until the onset of Korotkoff sounds and then renewed deflation in steps of 3 to 5 mmHg. On disappearance of the Korotkoff sounds, the prevailing cuff pressure is recorded and stored as the diastolic value (Figure 1). To register the Korotkoff sounds optimally, the microphone is positioned above the brachial artery.(ABSTRACT TRUNCATED AT 400 WORDS)