Dangerous versus useful hypertension (a holistic view of hypertension).

The authors aim to offer a holistic view on hypertension and its treatment. Their approach is fairly confrontational, particularly by suggesting that hypertension may play a role in optimizing the blood flow and enhancing oxygen delivery. An increase in blood pressure brings about a threat of catastrophes. Therefore hypertension might be considered as either a subsequent complication, or an inevitable adaptation. When changes of many complicated and complex mechanisms result in retention of sodium and water, then the treatment of this condition is so far the most logical conclusion, and possibly beneficial to the patient. This can be done by influencing the peripheral resistance or the load of vascular bed. However, in some cases a moderate overfilling of the system with no increase in heart rate could be interpreted as an optimal solution for organism that does not necessarily need to be medically treated. This may apply especially to young hypertensive patients, and in cases when no catastrophe is assumed to take place. Lowering the blood pressure to average population levels in each case, especially by means of aggressive therapy may not necessarily lead to improved tissue perfusion. A decrease in blood pressure reduces the risk of catastrophes. However, on the other hand, it can deteriorate the tissue perfusion and cause unfavorable long-term consequences.

[Essential hypertension--syndrome, or compensatory mechanism]. / Esenciálna hypertenzia ako syndróm alebo kompenzacný mechanizmus?

Diagnosis of essential hypertension is created per exclusionem--with exclusion of all, so called secondary hypertensions (nephrogenic, endocrine conditioned etc). Idea and the name-essential hypertension are unclear. We have a lot of hypotheses about mechanisms of hypertension but no one is explaining satisfactorily the "fixation" of hypertension. From this point of view essential hypertension looks more like a syndrome than disease sui generis. Authors analyzed all possible pathways of hypertension origin as well as compensatory mechanisms in peripheral circulation in effort to reach relevant tissue perfusion. If these mechanisms lead to salt and water retention the best mode of the treatment would be to influence volume and blood vessels lumen. It is clear that optimization of blood pressure is advantageous for prevention of vascular catastrophes (myocardial and cerebral infarction). Nevertheless inadequate lowering of the peripheral tissue perfusion (kidney, CNS) can lead to degenerative changes in tissues and to disturbances in centrally regulated processes of blood pressure.

Remodeling in myocardial infarction and body surface potential maps.

This study deals with the capabilities of body surface integral and departure maps to evaluate the chronic stage of myocardial infarction based on dividing the left ventricle into 12 segments. The effects of ventricular remodeling on electrocardiographic potential distributions are considered. A 61-year-old male patient was examined five times by body surface potential mapping during a period of 9 months after acute myocardial infarction. Integral maps were calculated for 60 ms after QRS onset and compared with mean data from a control group using departure maps. Integral maps showed a continual reduction of negative potentials in the lower half of the torso with time. The negative area covered the lower torso in the departure maps during the whole study, but its form and value changed. According to the location of the departure area, the surface projection of the scar moved from a position corresponding to inferior segments to a position corresponding to posterior segments. Its size also decreased. Echocardiographic examinations showed progressive enlargement of both ventricles with time. Therefore, the authors postulate that the changing pattern of body surface potential maps was mainly influenced by ventricular remodeling after myocardial infarction.

Body surface isochrone maps of peak R in normal adolescent girls.

The aim of our study was to evaluate the adequacy of a new mapping device for obtaining a reliable set of normal maps characteristic for this approach. We studied body surface isochrone maps of peak R in four healthy adolescent girls using the mapping system CARDIAG 128.1 with 80 unipolar leads placed in a regular grid. The constructed maps were compared with published data using 10 criteria. None of the maps obtained could be regarded as normal. After evaluating the reasons for the "abnormality", we assume that they could be caused mostly by the processing of signals. This fact can be eliminated by improving the existing software.

[Modification of the composition of the hypertrophic myocardium by beta adrenergic blockade]. / Modifikácia zlozenia hypertrofovaného myokardu betaadrenergickou blokádou.

Adaptation of the rabbit heart to volume load of the left ventricle is characterized by hypertrophic growth. This process involves an increase in the mass and changes in the composition of the myocardium. In the fifth week after perforation of the aortic valve an increase in phospholipid content and in mitochondria and a decrease in protein content was observed in the myocardium. These changes precondition a transient hyperfunction of the cardiomyocytes, but they presumably lead also to the eventual loss of contractile capacity. When the hypertrophic process occurs under conditions of nonspecific beta-adrenergic blockade, the required increase in left ventricular mass is achieved yet the content of phospholipids, proteins and mitochondria remains unchanged. Long-term blockade of beta-adrenergic receptors may be one of the modes of affecting the expression of cardiac genes in such a way that the hypertrophic myocardium does not develop conditions resulting in heart failure.

[The effect of long-term administration of metipranolol on passive diastolic properties of the hypertrophic ventricle]. / Vplyv dlhodobého podávania metipranololu na pasívne diastolické vlastnosti hypertrofovanej komory.

In the course of adaptation of the rabbit heart to volume load passive diastolic properties of the hypertrophic ventricle and myocardium were changing significantly. On day 30 following perforation of the aortic valve stiffness of the ventricle was reduced, yet normalized ventricular stiffness and myocardial stiffness were increased. These changes were prevented by beta adrenergic blockade during development of adaptation of the heart to volume load. Although ventricular stiffness was reduced, normalized ventricular stiffness and myocardial stiffness remained at the level of control values. The demonstrated effect of beta adrenergic blockade on passive diastolic properties of the ventricle and myocardium may be of value in preventing heart failure due to chronic hemodynamic load. (Tab.3,Ref.15.).