Pathophysiology of cardiogenic shock. Quantification of myocardial necrosis, clinical, pathologic and electrocardiographic correlations

Clinical and pathologic data were correlated in 22 patients with cardiogenic shock and 10 "control" patients who died suddenly after infarction without shock. A pathologic technique of ventricular mapping allowed quantification of recent as well as old infarction. Total left ventricular (LV) damage averaged 51% (range 35-68%) in the shock patients and 23% (range 14-31%) in the control group. Shock was associated with recent infarction (all 22 patients), old infarction (21 patients) and extension of infarction (18 patients). Extension, often in a subepicardial manner, averaged 6% of LV mass (range 3-10%) in 18 patients with shock; it preceded shock in four, coincided with the onset of shock in six, and followed shock in seven patients with shock. In contrast, small extensions averaging 2% of LV mass were found in three, and multiple recent infarctions in two control patients. Although progressive myocardial damage was a common pathologic finding, it was infrequently recognized clinically. The electrocardiogram reflected evidence of recent infarction in 56%, old infarction in 31%, and extension in only 30% of patients. These data suggest that appropriate early therapeutic intervention might limit myocardial damage by preventing extension or reinfarction. Since shock was best correlated with total LV damage, such limitation of infarction might reduce the incidence and mortality of cardiogenic shock.

Heart failure complicating acute myocardial infarction

Congestive heart failure (CHF) occurs in about one half of all patients with acute myocardial infarction and is a manifestation of acute alterations in left ventricular function. In the present study CHF is defined on clinical grounds, according to the presence and extent of bilateral pulmonary rales. An accompanying S 3 ventricular gallop was heard in 58% of our patients with heart failure initially, but it disappeared eventually in the majority. Dilatation of pulmonary veins and blurring of pulmonary vascular markings are useful roentgenographic signs which reflect elevations in left heart filling pressure. At times the earliest indicators of heart failure, these findings appear in general to be less sensitive than the physical examination in diagnosing CHF. Although stroke volume is decreased with CHF, cardiac index is generally maintained by increased heart rate. Left ventricular minute work and stroke work are significantly decreased, while left ventricular end-diastolic pressure is significantly increased, in patients with CHF complicating acute myocardial infarction. Arterial hypoxemia is common and the degree of arteriovenous shunting is roughly proportional to the elevation of left ventricular filling pressure. The mortality of patients with CHF is approximately three times that of patients with acute myocardial infarction and no complications. Diuretic therapy is safe and effective. Attention is called to the probability that the use of digitalis preparations in the early hours following myocardial infarction is hazardous. Furthermore, hemodynamic benefit from digitalization in the early postinfarction period remains unproven.

History of drugs for thrombotic disease. Discovery, development, and directions for the future

The history of the antithrombotic agents--aspirin, heparin, warfarin, and the thrombolytics--is a rich and lively odyssey of serendipity, perseverance, vision, and conflict involving a number of striking personalities. The history of aspirin spans ages and continents from Hippocrates' analgesic for women in labor to the rediscovery of the white willow bark by English country scholar Reverend Edward Stone. Bayer chemist Felix Hoffmann reinvented aspirin for his ailing father; suburban physician L.L. Craven pioneered the prophylactic antithrombotic uses of aspirin; and Sir John Vane elucidated aspirin's mechanism of action as the inhibition of prostaglandin synthetase. Heparin was discovered by McLean, working as a medical student in 1915 in search of a pure procoagulant in dog liver. His original impure material differed somewhat from today's heparin, but purified heparin was rapidly accepted for a myriad of clinical uses; to this day, diverse new properties of this complex glycosaminoglycan continue to be elucidated. The oral anticoagulants emerged from veterinary research in the 1920s on a hemorrhagic disorder afflicting cattle that consumed spoiled sweet clover hay. Several chance encounters led Karl Link and his University of Wisconsin team to the identification of dicumarol as the offending agent in 1939 and its widespread therapeutic use by Wright and others in the 1940s. Link later developed warfarin as a rodenticide, but its use in humans soon followed in the 1950s. Vitamin K was discovered in the 1930s; its involvement in the mechanism of the anticoagulant agents was not delineated until the 1970s. The intrinsic ability of clotted blood to liquify and the fibrinolytic properties of normal urine were noted in the 1800s. Tillett and Sherry's group stumbled on the fibrinolytic properties of streptokinase in the 1930s and pioneered the therapeutic use of streptokinase in the 1940s and of urokinase in the 1960s. Several teams found tissue-type plasminogen activator in various body sites beginning in the 1940s, leading to its cloning and widespread use in the 1980s; anisoylated plasminogen-streptokinase activator complex is an example of rational drug design. The discoverers of these diverse agents have not only provided physicians with a potent armamentarium of antithrombotic drugs but also helped elucidate much basic science and vividly demonstrated the merits of perseverance, independent thought, and adherance to the scientific method.

Myoglobinemia following acute myocardial infarction

Myoglobin was identified in the serum of 11 of 21 patients after myocardial infarction by a sensitive specific complement fixation technic. This method allowed detection of as little as 0.03 mug of myoglobin. The assay tended to underestimate small concentrations of myoglobin due to serum interference. Myoglobinuria occurred with myoglobinemia but did not reflect the level of myoglobinemia or the duration of elevated serum levels. Larger amounts of myoglobin, 0.4 mug/ml or greater, were found in patients with severe infarctions, three of four of whom died as a result of this illness.

Serum myoglobin in myocardial infarction: the "staccato phenomenon." Is acute myocardial infarction in man an intermittent event?

When serum was sampled frequently and soon after acute myocardial infarction, myoglobinemia was extremely common, occurring in 12 of 13 selected patients. Myoglobin first appeared in the serum within a few hours after infarction, but not consistently earlier than creatine phosphokinase. The peak level of serum myoglobin was reached appreciably earlier than the peak values of serum creatine phosphokinase activity. Time of earliest myoglobin appearance in the serum, peak level of myoglobin measured, and duration of detectable myoglobin release all correlated poorly with clinical and biochemical estimates of severity of myocardial infarction. There was no correlation between myoglobin levels and infarct size as estimated from creatine phosphokinase kinetics. Myoglobin appeared in the serum in multiple short "staccato" bursts, or episodes, often lasting only one to two hours. The hypothesis is suggested that the pattern of myoglobin appearance is a reflection of the episodic nature of acute myocardial infarction. Although isolated myoglobin determination may not be useful at present, for quantification of total myocardial damage, its pattern of release may be a sensitive marker for studying the time course of infarction, and may be useful to evaluate therapeutic interventions designed to interrupt an ongoing syndrome of myocardial necrosis.

Aspirin therapy in angina pectoris: effects on platelet aggregation, exercise tolerance, and electrocardiographic manifestations of ischemia

If altered platelet function contributes to poorly perfused zones of myocardium in patients with angina pectoris, then specific antiplatelet therapy might improve cardiovascular function and exercise performance. Exercise tolerance on a bicycle ergometer, heart rate-blood pressure product, and ischemic ECG changes at exercise end-point were compared before and during oral aspirin therapy (2.4 Gm. per day for 2 weeks) in 11 normal subjecs and in 11 patients with stable angina pectoris. Platelet aggregation threshold in response to ADP and epinephrine was measured. Untreated patients had increased platelet aggregability when compared to normal subjects...

Long-term effectiveness of verapamil in stable and unstable angina pectoris. One-year follow-up of patients treated in placebo-controlled double-blind randomized clinical trials

The clinical responses to 12 months' treatment with verapamil were evaluated in 63 patients with stable and unstable angina pectoris in whom the effectiveness of verapamil had been established in short-term double-blind placebo-controlled randomized clinical trials. In 41 patients with effort-related angina, long-term responses were sustained for periods exceeding 1 year. Twenty patients were evaluated by clinical history and showed a sustained reduction in frequency of anginal attacks and consumption of nitroglycerin with verapamil compared with the initial placebo control periods; the magnitude of this benefit was similar to that observed during double-blind treatment with the drug. Twenty-one patients were evaluated by serial treadmill exercise testing and showed a sustained improvement in exercise duration after 4, 8, 16, 24, and 52 weeks of verapamil treatment; withdrawal of the drug resulted in a deterioration of exercise performance to levels similar to those seen before initiation of therapy. In 22 patients with unstable angina at rest, verapamil produced an amelioration of anginal symptoms that was sustained in most patients for longer than 1 year. However, these patients continued to have a high incidence of death and myocardial infarction in a frequency similar to that previously reported in large clinical studies using either combinations of verapamil and nitrates, nifedipine and propranolol, or propranolol and nitrates. Calcium-channel antagonists may decrease the number of patients requiring coronary artery bypass surgery for relief of refractory angina, but they do not appear to alter the natural history of the disease.

Objective haemodynamic assessment after acute myocardial infarction

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Efficacy and safety of nicardipine for chronic, stable angina pectoris: a multicenter randomized trial

Nicardipine, a new calcium channel blocking drug of the dihydropyridine family, was administered to 63 patients at a dose of 30 or 40 mg 3 times daily in a multicenter, randomized, double-blind, placebo-controlled, crossover trial. Nicardipine midly increased heart rate (HR) at rest and midly decreased the blood pressure (BP) at rest. When generally similar responses to the 30- and 40-mg doses were averaged, nicardipine produced a 7% increase in peak exercise HR, which was balanced by a 6% decrease in peak exercise BP. Thus, no change occurred in the exercise HR-BP product. With nicardipine, treadmill exercise duration increased 9%, time to angina increased 15%, time to 1-mm ST-segment depression increased 16%, and oxygen consumption at peak exercise increased 13%. Mean anginal frequency declined, as did mean weekly sublingual nitroglycerin consumption, but not significantly. There were more cardiovascular side effects with nicardipine than with placebo, with at least 3 patients having increased angina judged by investigators as probably related to the drug. Vasodilatory side effects were also more frequent with nicardipine, but were generally mild and well tolerated; the drug had to be discontinued in only 1 patient, because of vasodilatory effects. Nicardipine is effective and generally well tolerated in patients with chronic stable angina.

Nicardipine for stable angina pectoris

Nicardipine, 30 and 40 mg thrice daily, was administered to 66 patients with stable angina pectoris in a multicentre, randomised, double-blind, cross-over trial. With nicardipine therapy, duration of exercise and cumulative oxygen consumption increased, while times to onset of angina and 1 mm ST segment depression were prolonged. Anginal frequency and nitroglycerin consumption declined with use of nicardipine, but this did not reach statistical significance. Resting heart rate increased slightly and resting blood pressure decreased. Two patients on nicardipine and one on placebo sustained acute infarction. Otherwise, side effects were generally mild and transient.

Group psychotherapy for patients with coronary heart disease

Group therapy with cardiac patients is a relatively new specialty. The field is supported by a substantial epidemiological and experimental literature demonstrating links between heart and mind. There are several clinical trials that have demonstrated less morbidity, improved quality of life, and, to some extent, lower mortality for patients who have received psychosocial intervention, generally group therapy, compared to control patients. Different theoretical orientations and a small number of clinical techniques have been developed to help cardiac patients make an adjustment to heart-healthy living. This article provides a brief review of the literature in cardiac psychology, suggestions for developing a psychotherapy practice specialty with cardiac patients, techniques for treating these patients, and conclusions by a psychologist-cardiologist team that has been active in this area for more than a decade.

When does intraoperative 3D-imaging play a role in transpedicular C2 screw placement?

INTRODUCTION

The stabilization of an atlantoaxial (C1-C2) instability is demanding due to a complex atlantoaxial anatomy with proximity to the spinal cord, a variable run of the vertebral artery (VA) and narrow C2 pedicles. We perfomed the Goel & Harms fusion in combination with an intraoperative 3D imaging to ensure correct screw placement in the C2 pedicle. We hypothesized, that narrow C2 pedicles lead to a higher malposition rate of screws by perforation of the pedicle wall. The purpose of this study was to describe a certain pedicle size, under which the perforation rate rises.

PATIENTS AND METHODS

In this retrospective study, all patients (n=30) were operated in the Goel & Harms technique. The isthmus height and pedicle diameter of C2 were measured. The achieved screw position in C2 was evaluated according to Gertzbein & Robbin classification (GRGr).

RESULTS

A statistically significant correlation was found between the pedicles size (isthmus height/pedicle diameter) and the achieved GRGr for the right (p=0.002/p=0.03) and left side (p=0.018/p=0.008). The ROC analysis yielded a Cut Off value for the pedicle size to distinguish between an intact or perforated pedicle wall (GRGr 1 or ≥2). The Cut-Off value was identified for the isthmus height (right 6.1mm, left 5.4mm) and for the pedicle diameter (6.6mm both sides).

CONCLUSION

The hypothesis, that narrow pedicles lead to a higher perforation rate of the pedicle wall, can be accepted. Pedicles of <6.6mm turned out to be a risk factor for a perforation of the pedicle wall (GRGr 2 or higher). Intraoperative 3D imaging is a feasible tool to confirm optimal screw position, which becomes even more important in cases with thin pedicles. The rising risk of VA injury in these cases support the additional use of navigation.

Lactate metabolism after aorto-coronary artery vein bypass grafts

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Ischemic heart disease: a patient-specific therapeutic approach with emphasis on quality of life considerations

Advantages and disadvantages of the various therapies for stable angina are considered with particular attention to quality of life. Advantages of coronary artery bypass surgery (CABS), apart from the question of survival, include less angina, less activity limitation, and less need for drugs than with medical treatment. However, data from the Coronary Artery Surgery Study (CASS) and others show that there is no difference between medical and surgical therapy in return to work and in need for subsequent hospitalization. In CABS patients, there is also predictable return of angina, substantial late vein graft occlusion, and possibly increased progression of native coronary artery disease in grafted vessels. Percutaneous transluminal coronary angioplasty (PTCA) has advantages similar to those of CABS, with very low initial mortality and major complication rates, minimal discomfort, very short disability period, and moderate cost. Its major disadvantages are a high short-term reocclusion rate and uncertain long-term outcome. Beta blockers provide good control of angina, have additional antihypertensive and antiarrhythmic effects, and may be beneficial in preventing sudden cardiac (arrhythmic) death and limiting myocardial infarct size, should these events supervene in the patient with angina. Disadvantages of beta blockers involve the occasional major side effects, including potential exacerbation of bronchospasm, peripheral vascular disease (PVD), diabetes, congestive heart failure and bradyarrhythmia, and frequent "nuisance" side effects. Calcium blockers control both exercise and rest angina and pose no problem in patients with bronchoconstriction, PVD, or diabetes. Disadvantages include need for frequent dosage, cost, and side effects. Long-acting nitrates have few major side effects and usually transient minor side effects, with little effect on quality of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Systematic Reviews and Meta-analyses

The rising number of medical publications makes it difficult to keep up-to-date on scientific knowledge. In recent years, reviews in the form of narrative or systematic publications and meta-analyses have increased. These can only be interpreted and evaluated if the reader understands the techniques used. This review article describes the differences between narrative and systematic reviews, together with the characteristics of meta-analysis, and discusses their interpretation. The concept of systematic reviews and meta-analysis includes a systematic literature search and summary, together with an appraisal of the quality of the publications. Systematic reviews are often considered to be original studies due to their structure and ability to reduce bias.

Changing mortality from coronary heart disease among smokers and nonsmokers over a 20-year interval

A comparison of coronary heart disease (CHD) mortality in two large American Cancer Society studies, Cancer Prevention Study (CPS) I (1959-1965) and CPS-II (1962-1968) suggests that surprisingly large declines occurred in two groups so defined to minimize the influence of change of smoking status. CHD mortality fell essentially in half when comparing nearly 300,000 persons who were actively smoking cigarettes at entry into CPS-I with about 228,000 persons who were similarly actively smoking at entry into CPS-II, about 20 years later. CHD mortality also declined by more than 50% among nearly half a million lifelong nonsmokers recruited for CPS-I in the early 1960s and for CPS-II in the mid-1980s. Possible explanations for these large declines include unmeasured decreases in smoking related to trial design, errors in ascertainment of causes of death, greater improvement among smokers of other risk factors for CHD, and changes in cigarettes or the pattern of smoking that have been salutary for CHD, but not for lung disease or lung cancer; none of these putative explanations can be supported by data from these studies. CHD mortality, much lower in absolute terms in recent years, is still much higher among smokers vs nonsmokers, so that the beneficial trends observed from CPS-I to CPS-II should stimulate further exploration of how CHD is related to smoking, and not serve as an excuse to ignore continued smoking.