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Goldman Cardiac Risk factors Nine independent risk factors are evaluated on a point scale : Third heart sound (S3); 11 Elevated jugulovenous pressure; 11 Myocardial infarction in past 6 months; 10 ECG: premature arterial contractions or any rhythm other than sinus; 7 ECG shows > 5 premature ventricular contractions per minute; 7 Age more than 70 years; 5 Emergency procedure; 4 Intra-thoracic, intra-abdominal or aortic surgery; 3 Poor general status, metabolic or bedridden; 3 Patients with scores >25 had a 56% incidence of death, with a 22% incidence of severe cardiovascular complications. Patients with scores <26 had a 4% incidence of death, with a 17% incidence of severe cardiovascular complications. Patients with scores <6 had a 0.2% incidence of death, with a 0.7% incidence of severe cardiovascular complications.

Heart Structure and Blood Supply It seems odd that the tissues making up the heart must have their own separate blood supply. You might think that the torrent of blood rushing through the heart every minute would more than adequately meet the needs of the organ. The walls of the heart, however, consist of layers of specialized muscle. These walls are quite thick—the wall of the left ventricle is often over 1 inch thick. Since the lining of the heart is watertight, the blood cannot seep through the layers of muscle to provide the nourishment essential to these constantly working masses. Blood is carried through the muscle layers that form the heart wall by means of the two coronary arteries. These two small vessels branch off the aorta just after it leaves the heart and curl back across the surface of the chambers, sending twigs through the walls (Fig. 4-1). The coronary arteries are so named because of the supposed resemblance to a crown or “corona” of the little arteries as they...

Blood Flow Through the Heart Blood is pumped through the chambers of the heart and out through the great vessels by a simple squeezing action of the heart chambers. You have probably seen a bulb syringe with a glass nozzle like the one pictured in Figure 3-1. Suppose it is full of water. If you squeeze forcefully, expelling the water, you would be imitating the contraction of a heart chamber. This is called systole (sis-toe-lee). After the syringe had been emptied, imagine that you placed the nozzle in a container of water and let the bulb expand so that it filled. This is what a heart chamber does when it relaxes and fills with blood. The movement is called diastole (die-as-toe-lee). You can picture the process by holding your left hand over your right, fists clenched. If your left hand represents the atria, your right hand will represent the ventricles. Now clench your left fist (the atria) while opening your right fist (the ventricles). This is what happens during atrial systole whe...

Valve Structure and Function Like any pump, the heart has valves to keep the blood flowing in the right direction. Proper function of these small flaps of tissue spells the difference between good health and sickness, and often between life and death. Almost everyone is familiar with the word valve. Very few people, however, really know what a valve is or what it does. Imagine pumping water through a pipe with a farm pump. To keep the water from flowing back toward the pump between strokes, you could place a valve in the pipe leading out of the pump. The simplest kind of valve would consist of two semicircular flaps hinged to open only one way—forward with the flow of water. These flaps would close the pipe completely when they swung shut. When the water flowed forward from the pump, the flaps of the valve would swing open allowing the water to pass. Between strokes the valves would snap shut if any water attempted to flow back toward the pump (Fig. 2-1). Note: The heart is equipped ...

Before you begin to learn about heart disease, you must learn how the normal heart is constructed and how it functions. This is easier than you might think, because the heart is a surprisingly simple organ. An hour's easy reading will give you all the information you need to begin. The Chambers of the Heart and their Connections The heart is a hollow organ divided into four chambers, two on the top and two on the bottom (Fig. 1-1). Study this simple diagram until you know it as well as your own name: it's basic to everything else in the book. The top two chambers are thin-walled structures that act primarily as holding chambers for the blood. They are called atria. This is the plural of the Latin word atrium, meaning “anteroom” or “porch,” and, in fact, these chambers do act as entryways to the great chambers below. The ventricles are large, thick-walled chambers that do the real work of pumping the blood. (This name comes from the Latin ventriculum, meaning a “cavity...

All patients with mechanical valves require warfarin therapy. The risk of embolism is greater with a valve in the mitral position (mechanical or biological) than in the aortic position. With either type of prosthesis or valve location, the risk of emboli is higher in the first few days and months after valve insertion. Low-dose aspirin is recommended for all patients with prosthetic valves (see Table 1. For patients with mechanical valves, the addition of low-dose aspirin (80 to 100 mg/d) to warfarin therapy (INR 2.0 to 3.5) not only further decreases the risk thromboembolism but also decreases mortality due to other cardiovascular diseases. A slight increase in risk of bleeding with this combination should be kept in mind. Recommendations for Antithrombotic Therapy in Patients With Prosthetic Heart Valves Class I 1.First 3 months after valve replacement: Warfarin- INR 2.5 to 3.5 2.3 or more months after valve replacement: A. Mechanical valve AVR and no risk factor*: Bileaflet valve or...

Treatment Because myocardial damage progresses rapidly during the early hours, efforts during this critical period must be directed toward reducing myocardial oxygen demand and improving coronary blood supply to diminish the extent of myocardial damage. To be maximally effective, these interventions must be initiated as soon as possible: The reduction in benefit is very time-dependent, and patients who are treated within an hour fare significantly better than those treated later. Thus, prompt reperfusion therapy via primary angioplasty or thrombolytic therapy should be initiated in the absence of contraindications as early as possible in patients with ST elevation acute infarctions. It is now becoming clear that urgent treatment also reduces the morbidity associated with non-Q wave infarctions as well, especially if followed by definitive intervention on the infarct related artery. A. EMERGENCY CARE AND PROTOCOLS More than 85% of patients who present with ST elevation within 4 h of the...

Clinical Findings The clinical presentations of patients with AMI vary. Although most patients have had chest discomfort prior to the onset of infarction, 20% or more have infarction as a first manifestation of ischemic heart disease; in 20–30% of patients, infarction may go unrecognized. Nonetheless, symptoms are generally present. A. SYMPTOMS AND SIGNS The most common and best symptom on which to base a consideration of MI is chest discomfort, usually described as “pressure,” “dull,” “squeezing,” “aching,” or “oppressive,” although it may be described differently because of individual variability, differences in articulation or verbal abilities, or concomitant disease processes. The discomfort is usually in the center of the chest and may radiate to the left arm or the neck. In general, patients with ischemic chest pain tend to be still, but patients with infarction can be restless as well. The nature of the pain may lead patients to place a hand over the sternum (Levine’s sign)...

It is generally accepted that a prolonged imbalance between myocardial oxygen supply and demand leads to the death of myocardial tissue. Coronary atherosclerosis is an essential part of the process in most patients. Ischemic heart disease seems to progress through a process of plaque rupture that transiently increases the amount of luminal impingement by the stenotic lesion. Infarction may occur when the plaque ruptures and leads to thrombosis, erosion of the plaque causes thrombosis, or when cardiac work exceeds the ability of the narrowed coronary artery to supply nutritive perfusion. Recent work suggests that inflammation may play a pivotal role in the genesis of plaque rupture. Greater numbers of acute infarctions occur during the early morning hours (from 6:00 AM to 12:00 noon) than any other time of the day, suggesting that perhaps the increased catecholamine secretion associated with awakening or circadian changes in coagulation common in the early morning (eg, increases in type...

A. GENERAL APPROACH Because myocardial ischemia is produced by an imbalance between myocardial oxygen supply and demand, in general, treatment consists of increasing supply or reducing demand—or both. Heart rate is a major determinant of myocardial oxygen demand, and attention to its control is imperative. Any treatment that accelerates heart rate is generally not going to be efficacious in preventing myocardial ischemia. Therefore, care must be taken with potent vasodilator drugs, which may lower blood pressure and induce reflex tachycardia. Furthermore, because most coronary blood flow occurs during diastole, the longer the diastole, the greater the coronary blood flow; and the faster the heart rate, the shorter the diastole. Blood pressure is another important factor: Increases in blood pressure raise myocardial oxygen demand by elevating left ventricular wall tension, and blood pressure is the driving pressure for coronary perfusion. A critical blood pressure is required that does ...