Noninvasive assessment of diabetic cardiovascular autonomic neuropathy (AN): Cardiac and vascular dysfunctions resulting from AN are complications of diabetes, often undiagnosed. Our objectives were to: 1) determine sympathetic and parasympathetic components of compromised blood pressure regulation in patients with polyneuropathy, and 2) rank noninvasive indexes for their sensitivity in diagnosing AN. Continuous 12-lead electrocardiography (ECG), blood pressure (BP), respiration, regional blood flow and bio-impedance were recorded from 12 able-bodied subjects (AB), 7 diabetics without (D0), 7 with possible (D1) and 8 with definite polyneuropathy (D2), during 10 minutes supine control, 30 minutes 70-degree head-up tilt and 5 minutes supine recovery. During the first 3 minutes of tilt, systolic BP decreased in D2 while increased in AB. Parasympathetic control of heart rate, baroreflex sensitivity, and baroreflex effectiveness and sympathetic control of heart rate and vasomotion were reduced in D2, compared with AB. Baroreflex effectiveness index was identified as the most sensitive index to discriminate diabetic AN. Four-dimensional multiscale modeling of ECG indexes of diabetic autonomic neuropathy: QT interval prolongation which predicts long-term mortality in diabetics with AN, is well known. The mechanism of QT interval prolongation is still unknown, but correlation of regional sympathetic denervation of the heart (revealed by cardiac imaging) with QT interval in 12-lead ECG has been proposed. The goal of this study is to 1) reproduce QT interval prolongation seen in diabetics, and 2) develop a computer model to link QT interval prolongation to regional cardiac sympathetic denervation at the cellular level. From the 12-lead ECG acquired in the study above, heart rate-corrected QT interval (QTc) was computed and a reduced ionic whole heart mathematical model was constructed. Twelve-lead ECG was produced as a forward solution from an equivalent cardiac source. Different patterns of regional denervation in cardiac images of diabetic patients guided the simulation of pathological changes. Minimum QTc interval of lateral leads tended to be longer in D2 than in AB. Prolonging action potential duration in the basal septal region in the model produced ECG and QT interval similar to that of D2 subjects, suggesting sympathetic denervation in this region in patients with definite neuropathy.

Die mittlere Höhe des arteriellen Blutdruckes (AP) ist von zentraler Bedeutung für das kardiovaskuläre Risiko Hochdruckkranker. Zusätzlich zeigen neuere Untersuchungen, daß Änderungen der Blutdruckdynamik eine wichtige Rolle in der Entwicklung hypertonieassoziierten Endorganschäden zukommt. Die Blutdruckvariabilität scheint in diesem Zusammenhang sogar einen eigenständigen Risikofaktor zu bilden. Der Einfluß kurzfristiger Blutdruckschwankungen auf zentrale Mechanismen der Langzeitblutdruckregulation, wie beispielsweise die renale Elimination von Natrium und Wasser, ist weitgehend unbekannt. Unsere Untersuchungen zeigen, daß schnelle Blutdruckschwankungen (BPO) kaum von der renalen Autoregulation der Durchblutung (RBF) unterdrückt werden können und zu Oszillation im Harnzeitvolumen führen. Es ist daher wahrscheinlich, daß BPO intrarenale System der Blutdruckregulation (wie beispielsweise das Renin-Angiotensin-System oder die schubspannungsabhängige Freisetzung von Stickoxid) modulieren können. Um diese Hypothese zu testen wurde der Einfluß von 0,1Hz BPO auf die Entwicklung eines renovaskulären Hypertonus untersucht. BPO um 85mmHg senkten signifikant die Plasmareninaktivität, erhöhten die tägliche Ausscheidung von Wasser, Natrium und Kalium und induzierten einen transienten Anstieg der Nitratspiegel im Urin wobei eine deutliche Senkung des arteriellen Blutdruckes beobachtet wurde. / The average level of arterial blood pressure (AP) is a major determinant of future cardiovascular complications in hypertension. In addition, recent investigations demonstrate that the dynamic properties of BP are of significant importance for the development of hypertension - related end organ damage in patients. Thus, hypertension - related changes in blood pressure dynamics seem to establish an independent risk factor for cardiovascular complications. Little is known regarding the influence of such short - term changes in AP on kidney function, a crucial control element for long - term AP regulation. Our investigations show that fast blood pressure oscillations (BPO) are not effectively buffered by renal blood flow autoregulation and induce oscillations in urine flow. It seems, therefore, likely that AP fluctuations can modulate intrarenally located systems involved in blood pressure regulation (e.g., renin release or shear stress dependent release of endothelium derived nitric oxide). To test this hypothesis we investigated the impact of induced BPO with a frequency of 0.1Hz on the onset of renovascular hypertension. BPO around 85mmHg significantly decreased plasma renin activity, enhanced 24h fluid, sodium and potassium excretion, and induced a transient increase in urinary nitrate excretion, thereby, attenuating renovascular hypertension.

Abstract not available

The purpose of this project was to evaluate the effectiveness of an educational lifestyle modification (LM) intervention on blood pressure (BP) among adults with prehypertension. Prehypertension is a precursor to hypertension (HTN) and is a public epidemic in the United States. Approximately 68 million (31%) U.S. adult’s aged ≥18 years have hypertension. Hypertension can cause significant target organ damage, lead to coronary heart disease, heart failure, stroke, and kidney failure. Early identification and the primary treatment of persons with prehypertension with LM have the potential to minimize the progression and delay the onset of comorbidities associated with hypertension. This quality improvement project retrospectively reviewed changes in blood pressure for a small sample (n=5) of patients diagnosed with prehypertension who received education about modifying lifestyle behaviors according to nationally accepted clinical practice guidelines. Blood pressure measurements were extracted from the medical record beginning at the time of the education through a three month period. Descriptive data indicates that all five patients had a decrease in systolic and diastolic blood pressure. The median systolic blood pressure at baseline was 129 mmHg decreasing to 121 mmHg at end of study period. The median diastolic blood pressure was 86 mmHg decreasing to 76 mmHg. Integration of lifestyle modification education and subsequent blood pressure monitoring during a routine primary care visit is feasible and may help motivate patients to implement changes and subsequently reduce blood pressure. Future studies should include identifying strategies for improving patient participation.