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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertension is a powerful predisposing risk factor for cardiovascular disease at all ages and in both sexes. Epidemiological assessment indicates the largest risk ratios for stroke and congestive heart failure (CHF), but coronary heart disease (CHD) is the most common and most lethal sequela of hypertension. Examination of the risk of cardiovascular sequelae in the hypertensive population indicates that this is not uniform and varies over a 10-fold range, depending on the associated risk factors. Systolic pressure merits greater consideration than the diastole pressure because isolated systolic hypertension is a powerful cardiovascular risk at all ages. Furthermore, recent trials have indicated the benefit of therapy for systolic-based hypertension in the elderly, even using a diuretic, for coronary disease as well as stroke. Persons with hypertension have a high prevalence of associated cardiovascular risk factors, including elevated cholesterol, reduced HDL-C, diabetes, left ventricular hypertrophy (LVH), and obesity. About 9% under the age of 65 years have an associated overt cardiovascular disease; above age 65 about 30% are so afflicted. Each of these risk factors can double the risk associated with hypertension. Because they are so common, a large fraction of the disease sequelae of hypertension is attributable to these associated risk factors. The high risk of coronary disease in hypertensive patients is concentrated in those with a high total/HDL-cholesterol ratio, impaired glucose tolerance, high fibrinogen, ECG abnormalities, and cigarette smokers. Stroke risk in hypertensive persons is concentrated in those with cardiovascular disease, diabetes, atrial fibrillation, LVH and cigarette smoking.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Potency of vascular risk factors as the basis for antihypertensive therapy. 148 3

Cigarette smoking is the most preventable cause of cardiovascular morbidity and mortality. Smoking has been associated with a two-to fourfold increased risk of coronary heart disease, a greater than 70% excess rate of death from coronary heart disease, and an elevated risk of sudden death. These risks are compounded in the presence of hypertension, hypercholesterolemia, glucose intolerance, and diabetes, all of which exhibit a synergistic effect with smoking. The relationship between smoking and the risk of peripheral vascular disease has also been well documented. Smokers account for approximately 70% of patients with atherosclerosis obliterans and virtually all those with thromboangiitis obliterans. An association between smoking and cerebrovascular disease remains a matter of debate, although a higher risk of stoke and stroke-related mortality has been observed in smokers than in nonsmokers. Smoking has also been implicated in the development of cor pulmonale, but a direct association with congestive heart failure has not been established. Nicotine and carbon monoxide appear to play major roles in the cardiovascular effects of smoking. Both components adversely alter the myocardial oxygen supply/demand ratio and have been shown to produce endothelial injury, leading to the development of atherosclerotic plaque. Adverse effects on the lipid profile have been noted as well, but the relationship between these changes and the risk of cardiovascular disease remains to be confirmed. Notably, smoking cessation results in a dramatic reduction in the risk of mortality from both coronary heart disease and stroke. In light of the fact that the incidence of smoking has declined primarily among educated sectors of the U.S. population, future efforts must focus on providing effective education, including smoking cessation techniques, to the less-educated groups.
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PMID:Smoking and cardiovascular disease. 149 5

The long-term results of patients undergoing myotomy/myectomy of the ventricular septum for obstructive hypertrophic cardiomyopathy are documented in 31 patients (15 women, 16 men, age range 21 to 80 years [mean 55]) with mean New York Heart Association functional class III to IV congestive heart failure, who underwent radical myotomy/myectomy at the Brigham and Women's Hospital from 1972 to 1991. Preoperative gradients by catheterization or echocardiography ranged from 26 to 240 mm Hg (average 96). There were no operative deaths. Two patients developed early postoperative complete heart block requiring a transvenous pacemaker. Clinical follow-up was 1 to 14 years (mean 6.5). All surviving patients were restudied by echocardiography and clinical examination. The mean postoperative functional class was II. Postoperative gradients ranged from 0 to 30 mm Hg (mean 4.5) (p less than 0.001 compared with preoperative values). There were 5 late deaths (low cardiac output in 2, stroke in 2, and acute respiratory failure in 1); 4 of 5 deaths occurred in patients with concomitant coronary artery disease. Survival at 10 years was 86 +/- 9%. There were no reoperations for subaortic obstruction.
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PMID:Long-term follow-up of patients undergoing myotomy/myectomy for obstructive hypertrophic cardiomyopathy. 151 16

A left ventricular assist device was used to produce a 90% reduction in peak systolic left ventricular pressure in pigs with congestive heart failure, and the resultant effects on right ventricular function were determined. Initially, eight farm pigs underwent rapid ventricular pacing at 230 beats/min for 7 days to produce congestive heart failure. When compared with an independent series of normal pigs, cardiac output in the paced animals was 33.3% less (2.2 +/- 0.2 versus 3.3 +/- 0.5 L/min; p less than 0.05), left ventricular end-diastolic pressure was elevated (13.8 +/- 3.5 versus 6.6 +/- 1.8 mm Hg; p less than 0.05), and the slope of the right ventricular global stroke work curve was significantly depressed (0.004 +/- 0.001 versus 0.033 +/- 0.003 joules/mm Hg; p less than 0.05). Next, the left ventricular assist device was connected between left ventricular apex and ascending aorta and left ventricular pressure was reduced from 92.0 +/- 3.8 to 10.5 +/- 2.2 mm Hg, while systemic arterial pressure was maintained constant. This led to a further impairment in cardiac output (-14%), mean arterial pressure (-15%), and the slope of the right ventricular global stroke work curve (-50%). Under each condition, right ventricular preload recruitable stroke work and end-systolic pressure-dimension relationships were studied in three different regions on the right ventricle during both steady-state and transient inferior vena caval occlusion. In the right ventricular septal-free wall dimension, left ventricular pressure unloading resulted in a 47.5% +/- 5.4% (p less than 0.05) reduction in the slope and 20.1% +/- 4.8% (p less than 0.05) increase in the dimension intercept of the preload recruitable stroke work relationship. There was also a 44.6% +/- 4.8% (p less than 0.05) reduction in the slope and 15.6% +/- 2.8% (p less than 0.05) increase in the dimension intercept of the end-systolic pressure-dimension relation. These slope changes plus reductions in cardiac output and in global stroke work, which are indicative of impaired right ventricular function during left ventricular pressure unloading in the congestive heart failure pigs, are not seen in normal hearts, whereas the intercept changes associated with leftward septal shift are present in both. These results suggest that anatomic ventricular interactions have a more significant role in heart failure than in the normal heart in determining overall right ventricular function during left ventricular assist device support.
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PMID:Right heart function during prosthetic left ventricular assistance in a porcine model of congestive heart failure. 151 47

Phosphodiesterase III inhibitors have been established in recent years in the therapy of congestive heart failure. Many disadvantages, such as extensive vasodilation and the lack of proven positive inotropic properties combined with thrombepenia and elevation of transaminases, have complicated the handling of the drug in clinical practice. Enoximone, an imidazole derivative, has been demonstrated to be more cardioselective and vasodilation has been found to be less pronounced than with amrinone. As a consequence, research was performed to enhance the cardioselectivity of phosphodiesterase III inhibitors by reduction of non-specific cross-reactivity with other phosphodiesterases, and R80122 (Janssen Pharmaceutics, Belgium) was introduced into clinical practice. R80122 ((E)-Ncyclohexal-N-methyl-2[[[phenyl (1,2,3,5-tetrahydro-2 oxoimidazo [2,1b]-quinazolin-7-yl)methylene] amino] oxy] acetamide) is a selective inhibitor of phosphodiesterase (PDE) IIIc, which is localized in the myocardium. Thus, its inhibition leads to a positive inotropic effect, whereas phosphodiesterase IIIRo is found in the vessel wall and causes vasodilation. This study was performed to investigate the hemodynamic profile of R80122 under clinical conditions. Additionally, the intestinal hemodynamics were recorded and changes in intestinal perfusion compared with changes in global hemodynamics. METHODS. The study was thoroughly discussed and approved by the local ethics committee; all patients gave written informed consent. The investigation was performed on ten male patients who were about to undergo elective coronary artery bypass surgery. History, physical examination and laboratory results were within the normal limits and revealed no evidence of liver disease. The usual medication was continued until the day before the operation. Premedication consisted of 2 mg flunitrazepam p.o. in the evening before the operation and 1.5 h before induction of anaesthesia. The determination of hepatic plasma flow was performed by the indocyanine green (ICG) infusion extraction technique using liver vein catheterization. After induction of anaesthesia (MP1), after application of a bolus dose of R80122 (0.3 mg/kg BW) (MP2) and at sternotomy (MP3), hemodynamic data (heart rate, arterial pressure, cardiac output) were recorded and blood samples for the determination of hepatic plasma flow by the concentration of ICG were collected. Anaesthesia was induced with a bolus dose of 0.2 mg/kg BW etomidate, 7 micrograms/kgBW fentanyl and 0.1 mg/kgBW pancuronium and maintained with a continuous infusion of 20 micrograms/min fentanyl, 300 micrograms/min midazolam and mechanical ventilation with O2/N2O at an FiO2 of 0.5. Statistical analysis was performed using the Wilcoxon-Mann-Whitney U test comparing the results after induction of anesthesia (MPI) with those after application of R80122 (MPII) and the results of MPII with those at sternotomy (MPIII). Statistical significance was assumed at P less than 0.05. RESULTS. After the induction of anaesthesia, the median heart rate (HR) was 56/min and did not change after administration of R80122. During sternotomy there was a significant increase in the HR from 64 to 78/min (P less than 0.05). Median arterial blood pressure (MAP) tended to decreased from 91 mm Hg after induction of 77 mm Hg after administration of R80122, although there was no statistical significance because of interindividual differences in the tendencies. At sternotomy, MAP remained unchanged. Cardiac output (CO) increased by 60% after administration of R80122 (P less than 0.01) and did not change during sternotomy. As a consequence of the changes in HR and CO, stroke volume (SV) increased by 22% after administration of R80122 (P less than 0.025) and decreased to control values during sternotomy.
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PMID:[Effects of R80122. The influence of a new phosphodiesterase inhibitor on global and intestinal hemodynamics in coronary surgery patients]. 152 59

We retrospectively reviewed the records of 88 patients who underwent a total of 95 in-situ bypass operations. Seventy-eight percent were diabetics, 56% hypertensives, 23% had a history of a myocardial infarction, 18% a previous stroke or transient ischemic attack, and 19% a renal transplant. Eighty-eight percent had general anesthesia. Eighty-four percent of the operations extended distal to the popliteal trifurcation, with an average operating time of 5.12 +/- 1.25 hours and blood loss of 354 +/- 239 ml. The overall mortality was 4.2%, with two deaths due to wound sepsis and two deaths due to congestive heart failure. The perioperative myocardial infarction rate was 6.3%. The average age of the patients who died was significantly greater than the age of those who survived (78.2 +/- 17.7 years vs. 59.9 +/- 14.8 years, p less than 0.05). The Goldman risk index was not helpful in predicting cardiac complications. The results show that patients undergoing in-situ bypass operations are at high risk for cardiovascular complications. Aggressive perioperative evaluation and management similar to that shown to reduce such complications in abdominal aortic aneurysm surgery should be helpful.
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PMID:Complications and mortality of the in-situ saphenous vein bypass for lower extremity ischemia. 153 65

Our review of the current literature and experience in caring for pacemaker patients suggests that a consideration of hemodynamics is a logical way to approach pacemaker selection and programming. Multiple clinical factors enter into the selection of a pacemaker or pacemaker programming settings in each case. It appears that in patients with sinus node disease, atrial-inhibited or dual-chamber pacing provides the best chance for preventing the development of chronic atrial fibrillation with its attendant risks of embolism and stroke. It is clear that AV synchrony has beneficial hemodynamic effects at rest in most patients. The results of Labovitz would suggest that in patients with marked left atrial enlargement, this may be less so. The results of Stewart et al would further suggest that in patients with retrograde VA conduction, dual-chamber pacing is preferable. Retrograde VA conduction can be intermittent and this makes it difficult to use its absence on a single test to decide on the type of pacemaker to use. It appears that baseline left ventricular function does not determine the relative improvement in cardiac output observed with AV synchrony or rate-adaptive pacing. However, in patients with severe congestive heart failure even a small improvement in cardiac output may result in significant clinical improvement. Studies have shown that in any given patient, there may be an optimal AV interval at rest. In general, this ranges from 100 to 150 milliseconds. In normal individuals the optimal AV interval shortens with increased heart rate during exercise in a predictable and linear fashion. The hemodynamic benefits of a shortened AV interval with faster heart rates in pacemaker patients have not yet been shown. Intuitively, however, this would appear to be a desirable approach and will probably be added to the design of future generations of dual-chamber pacemakers. Studies of the effect of different pacing modes on secretion of atrial natriuretic factor are intriguing and may contribute more to our understanding of pacing hemodynamics in the future. During exercise, heart rate increase is more important than AV synchrony and this has been shown by several studies. Thus, in active patients with chronotropic incompetence due to sick sinus syndrome, the addition of rate-adaptive pacing is important. Because single-chamber rate-adaptive atrial pacing leaves the patient exposed to the risk of future development of AV block and DDD pacing does not provide chronotropic support, it is likely that the new rate-adaptive dual-chamber (DDDR) devices will be used in a significant number of these patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pacemaker hemodynamics: clinical implications. 154 30

In a randomized, placebo-controlled, double-blind study, 12 patients with congestive heart failure (New York Heart Association class II) were successively treated for 1 week each with placebo, 40 mg famotidine, and 1000 mg quinidine. On the seventh treatment day, heart rate, blood pressure, systolic time intervals, impedance cardiography, and Doppler ultrasound were measured. Heart rate and blood pressure were not markedly altered by either drug. By contrast, quinidine and famotidine significantly decreased stroke volume and cardiac output in impedance cardiography and Doppler ultrasound (p less than 0.05). A high correlation between both noninvasive methods was found for cardiac output and stroke volume (r = 0.93 and r = 0.97 for stroke volume 1 1/2 hours after quinidine and placebo administration, respectively). In addition, the mechanocardiographic ratio of the preejection period to the left ventricular ejection time in systolic time intervals increased significantly 1 1/2 and 3 hours after administration of quinidine and famotidine (p less than 0.05). In conclusion, both quinidine and famotidine exert similar negative effects on cardiac performance, with no significant differences in hemodynamic parameters emerging between the antiarrhythmic agent and the H2-receptor antagonist.
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PMID:Hemodynamic effects of quinidine and famotidine in patients with congestive heart failure. 154 89

Despite multiple, interdisciplinary group recommendations, we are still on uncertain ground when it comes to treatment of most aspects of hypertension. Seven major areas of controversy include mild hypertension, the relevance of hypertension and lipids, hypertensive agents and electrolyte imbalance, treatment and regression of left ventricular hypertrophy, isolated systolic hypertension, ambulatory blood pressure monitoring and overtreatment of hypertension--the "j shaped curve." Although our knowledge of these aspects has advanced tremendously, significant doubts exist as to our present approach. Key publications are reviewed to evaluate our present knowledge and recommendations are made. The 1988 recommendations of the Joint National Committee on Detection, Evaluation and Treatment of Hypertension both answered and raised some questions regarding treatment of high blood pressure. We lack information on the treatment outcomes and many of us remain unconvinced that our present approach is the best we can do. Many other questions abound. Should the treatment of mild hypertension be as aggressive as it is at present or should systolic hypertension in the elderly be treated at all? There are striking variations and recommendations of other groups outside the United States which reaffirm our lack of evidence. Ideally, we ought to be able to reduce or abolish the recognized poor outcomes of treated hypertension: heart attack, heart failure, stroke, renal failure and retinopathy. Adequate control of blood pressure has gone a long way towards preventing stroke, accelerated hypertension and hypertensive encephalopathy. Congestive heart failure has also been reduced. There is a singular lack of evidence of the influence on either total mortality or morbidity from coronary events.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:New controversies in hypertension: questions answered, answers questioned. 154 98

We present a surgical technique that we believe provides superior cerebral protection for simultaneous correction of carotid and cardiac pathology with low operative mortality and stroke rate. Our study population consists of 23 consecutive patients undergoing cardiac operation between August 1989 and April 1991 who also had associated critical (greater than 85%) carotid artery stenosis. Using 20 degrees C systemic hypothermia for cerebral protection, we performed simultaneous correction of both lesions during the aortic cross-clamp period, using continuous retrograde blood cardioplegia for myocardial protection. Mean patient age was 69.4 years; 83% were 65 years or older. Eighty-seven percent had angina, 35% had recent myocardial infarctions (within 30 days), and 52% had congestive heart failure. Asymptomatic bruit was found in 39%, and 61% had previous strokes, neurologic symptoms, or both. All had 85% or greater luminal narrowing on cerebral angiography, with 65% having severe or critical contralateral disease as well. Sixty-one percent had associated other vascular pathology, including peripheral vascular occlusive disease, renal artery stenosis, or abdominal aortic aneurysm. There were no postoperative strokes or neurologic events. One early vein graft occlusion resulted in postoperative myocardial infarction and subsequent death (4.3%).
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PMID:Combined cardiac operation and carotid endarterectomy during aortic cross-clamping. 843 Oct 83


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