Multisite ventricular pacing

Many patients with advanced IDC have abnormal left ventricular activation that in turn results in prolonged and incoordinate ventricular relaxation. In some patients ventricular conduction delay is also associated with prolongation of atrioventricular conduction, resulting in a loss of atrioventricular synchrony and a predisposition to prolonged functional mitral regurgitation. Dual chamber pacing has been advocated as a method for restoring AV synchrony and improving left ventricular...

Pulmonary artery stenoses

Pulmonary artery stenosis occurs most frequently in patients with tetralogy of Fallot. It may be present before surgery or may appear early or late after surgical repair (fig 28.1). It may be easily missed, particularly in adults and particularly when it is unilateral. Surgical repair of pulmonary artery stenosis may be technically difficult and narrowing may recur because of patch scarring and shrinkage, so when stenosis of a major branch occurs after surgery most centres would try...

Pathology of outofhospital death

What proportion of out-of-hospital deaths are caused by developing infarction, and what proportion are caused by a re-entrant arrhythmia Sudden unexpected death in England must be reported to a coroner unless the victim was known to have coronary disease and had been seen by a doctor within the last two weeks. Depending on the practice of individual coroners, the proportion of unexpected deaths coming to necropsy is high. However, developing infarction cannot be recognised in most cases of...

Iaortopulmonary collaterals

Obstruction to flow in the superior caval vein rarely occurs de novo. It is usually a consequence of scarring related to surgery, to the presence of venous catheters or pacemaker electrodes, or external compression by tumour. When obstruction occurs insidiously there may be no symptoms and no indication to intervene, but with rapid onset obstruction, when collateral veins have not had time to develop and enlarge, venous hypertension in the head and neck will prompt treatment (fig 29.1)....

Idiopathic right ventricular outflow tract tachycardia

The most common idiopathic VT originates from a focus in the outflow tract of the right ventricle (fig 25.1).12 The mechanism is most likely triggered automaticity.4 VT has a left bundle branch block configuration in ECG lead V1 with a frontal plane axis that is directed inferiorly or inferiorly and to the right. Premature ventricular contractions with an identical morphology are often present during sinus rhythm. Tachycardia may occur in repetitive bursts (referred to as repetitive monomorphic...

Arrhythmogenic right ventricular dysplasia

Arrhythmogenic right ventricular dysplasia is associated with fibrous and fatty scar tissue in the right and often the left ventricles. VT typically has a left bundle branch block-like configuration in V1, consistent with a right ventricular origin. When right ventricular involvement is extensive, the success of ablation is variable.11 Individual VTs can be ablated, but others may develop later possibly related to progression of the disease process. Ablation is reserved as a palliative...

Coronary revascularisation in heart failure patients

*For all patients with viable myocardium the three year mortality rate was 8 (80 had CABG). For patients with only fixed scar > 23 mortality rate was 50 (p 0.018). Only 40 had CABG with no difference in mortality with or without CABG. EF, ejection fraction. High risk coronary bypass is the most frequent conventional operation in heart failure patients. Incomplete myocardial infarction leaves viable but ischaemic myocardium within involved segments (flow metabolism mismatch). Hibernating...

Current clinical application

Catheter ablation is a useful treatment for selected patients with VT. It should be considered for patients with recurrent, symptomatic idiopathic VT and is the first line treatment for bundle branch re-entry VT. Catheter ablation offers improved arrhythmia control in two thirds of patients who have a mappable scar related VT (table 25.1). It can be lifesaving for patients with incessant VT, and can decrease frequent episodes of VT causing therapies from an implanted defibrilla-tor. Before...

Unstable monomorphic VT

Two approaches are being evaluated for ablation of scar related VT that is difficult to map with a roving catheter because of haemo-dynamic instability or instability of the re-entry circuit. One approach involves defining the area of scar from its low amplitude sinus rhythm electrograms (fig 25.2, top panels) then selecting portions of the scar likely to contain a part of the re-entry circuit based on the VT QRS morphology or pace mapping and then placing a series of anatomically guided...

Valve replacement for symptomatic aortic stenosis

Aortic valve replacement remains the definitive treatment for symptomatic aortic stenosis. In recent surgical series, operative mortality averages 2-9 with long term survival rate of 80 at three years (table 16.1). Aortic stenosis in adults is rarely amenable to repair although commissurotomy may be an option in carefully selected young adults with non-calcified valves. Alternative procedures, such as balloon aortic valvuloplasty and surgical or ultrasonic valve debridement have not been...

Frailty of the elderly

Elderly patients with valve disease present with associated comorbidities (table 17.1) as well as reduced defence and adaptation capabilities. The aging process and atherosclerosis have undermined the reserve of many organs that are bound for postoperative dysfunction, or have already induced altered function. Furthermore, atherosclerosis frequently involves the aorta. Any manipulation of the aorta (cannula-tion for arterial inflow during cardiopulmonary bypass, cross clamping, and placement of...

Mild to moderate aortic stenosis in patients undergoing coronary artery bypass surgery

Recent prospective studies have demonstrated that about 75 of patients with initially asymptomatic aortic stenosis develop symptoms requiring valve replacement within the next five years. This observation has led to the suggestion that valve replacement be performed at the time of coronary artery bypass surgery when mild to moderate stenosis is present to preclude the need for repeat surgery in the next few years. Surgical mortality rates for repeat surgery for aortic valve replacement are high...

Aortic valve stenosis

Calcific aortic stenosis is the most common valve disorder encountered in octogenarians, and accounts for 60-70 of the valve surgery caseload.4 5 In a population based study, significant aortic stenosis was found in 2.9 of randomly selected people aged 75-86 years, half of whom had symptoms. This figure predicts a yearly potential need for 3500 aortic valve replacements in octogenarians in a country like England. Replacement of a stenotic aortic valve (and myocardial revascularisation limited...

Rationale for surgery before symptom onset

There clearly are a few situations in which aortic valve replacement is appropriate in asymptomatic patients. Examples include patients with evidence of left ventricular systolic dysfunction caused by aortic stenosis, young women with severe stenosis who desire pregnancy, patients with asymptomatic severe disease who plan activities that involve severe exertion or who live in areas remote from medical care, and adults with very severe Figure 16.3. Cox regression analysis showing event free...

Overall outcome in unstable anginanonST elevation myocardial infarction

Based upon prospective international registry data among 8000 patients in six countries, the risk of death or myocardial infarction is approximately 10 at six months and almost a quarter of patients sustain these events or acute refractory angina within six months of initial presentation (OASIS registry).2 Overall, half of these events occur within the first seven days of presentation. Based on those included Table 3.2 Braunwald classification of unstable angina I New onset, severe or...

Management of unstable angina and minimal myocardial injury

Presentation and general measures Patients with an acute coronary syndrome may present de novo with new onset angina CCS (Canadian Cardiovascular Society) class III or IV, or following abrupt deterioration of previously stable angina with more severe and prolonged symptoms and diminished responsiveness to glyceryl trinitrate. The Predicting adverse risk in unstable angina and minimal myocardial injury (summary) - prior myocardial infarction or heart failure - comorbidity diabetes, hypertension...

Practical recommendations

In patients with acute coronary syndromes, management should be risk based from the time of arrival in the emergency room (fig 4.5). An ECG and troponin assay should be obtained immediately with repeat troponin assay at 12 hours.15 Patients with regional ST change (elevation or depression) or left bundle branch block are a high risk group requiring admission to the coronary care unit and appropriate antithrombotic treatment. Patients with an ECG that is normal, or shows non-diagnostic T wave...

Adenosine diphosphate antagonists

The platelet adenosine diphosphate inhibitor clopidogrel has been employed as an adjunctive antiplatelet agent during coronary stenting. It appears to offer similar benefits to those of ticlopidine but with a more favourable safety profile (severe neutropenia as infrequent as that of aspirin 0.04 clopidogrel v 0.02 aspirin). Chronic treatment with clopidogrel offers approximately a 9 risk reduction compared with aspirin treatment and it is specifically indicated in those with aspirin...

Indications for PCI in chronic coronary artery disease

The indications for PCI have expanded during the past two decades, and no absolute contraindications remain (table 8.3). Single vessel coronary artery disease (CAD) remains the principal indication for PCI, with over 80 w74 of procedures performed in Europe and over 90 in the USA. This exponential growth of PCI has been largely at the expense of medical treatment rather than surgical revascularisa-tion. Beside clinical and angiographic factors, operator volume has been recognised as a major...

The declining mortality from coronary heart disease

There is no doubt that mortality from coronary heart disease is falling. Figure 6.410 shows that age specific mortality for males aged 35-44 years during 1997 was about one third, and of those aged 65-74 years about two thirds of the figures for 1968 when the coronary epidemic was at its height. Age groups 45-54 and 55-64 showed intermediate changes and the picture was similar in women. Data in fig 4 stop at age 75, however. If evidence from death certificates is to be believed, more than 60 of...

Evidence for an association between childhood factors and heart disease risk

Heart disease morbidity and mortality The first studies reporting an association between birth weight and CHD came from Hertfordshire and Sheffield study populations.4 8 Both in men and women even though the relation was weaker in women9 CHD mortality decreased progressively with increasing birth weight. Since then there have been several, mainly retrospective cohort studies which have replicated these observations and also demonstrated the association between size at birth and non-fatal...

Antithrombin treatment

Unfractionated heparin is widely used in the management of patients with unstable angina or minimal myocardial injury, although the evidence supporting its use in the absence of aspirin treatment is less robust than in the presence of aspirin. Maintaining accurate anti-thrombin control with unfractionated heparin is unpredictable because of plasma proteins binding, including that induced by acute phase proteins. There is reduced effectiveness in the presence of platelet rich and clot bound...

Therapeutic implications of plaque biology

Angiographic studies have shown that effective lipid lowering with statins reduces the incidence of new lesion formation and produces a significant, but haemodynamically unimportant (0.04-0.07 mm), improvement in established stenoses.15 Importantly, however, they also reduce the rate of progression of preexisting lesions and the number of new vessel occlusions. Both of these beneficial effects are likely to be due to prevention of plaque rupture since, as discussed above, lesions grow by...

Frequency of coronary artery disease in patients with calcified aortic stenosis

The frequency of coronary artery disease in patients with calcified aortic stenosis can be correctly assessed only in studies comprising systematic coronary angiography, regardless of the symptoms. The frequency of associated coronary disease varies according to the characteristics of the population involved, in particular age and, to a lesser degree, the geographic origin. Series of patients with calcific aortic stenosis whose mean age is between 60 and 70 years reported 30-50 of associated...

Effect of drugs on long term arrhythmia mortality

Showed trends to increased mortality. In CAST-II, moricizine was found to increase mortality notably in the two weeks following the institution of treatment, although the effect long term was less striking than with flecainide and encai-nide. A meta-analysis10 and a non-randomised post-hoc analysis11 suggested that quinidine or procainamide treatment in patients with atrial fibrillation was associated with a higher mortality than among patients not receiving these agents. The role of...

Risk stratification in the acute phase of coronary syndromes

Ventricular fibrillation, the major determinant of risk in the acute phase, requires immediate electrical cardioversion to avoid death. Because it is largely unpredictable, electrocardiographic monitoring and ready access to a defibrillator are the most important management strategies for saving lives in acute coronary syndromes. Also important is antithrombotic treatment which should be given to all patients acutely, with daily aspirin continuing thereafter. In other respects, management in...

Suggested biologicalenvironmental mechanisms underlying the evolution of heart disease risk

Intake, suggested that women who have a high intake of carbohydrates in early pregnancy and a low intake of dairy protein in late pregnancy tend to have infants who are thin at birth.w40 w41 Other indicators of possible disturbed fetal nutrition not directly related to maternal nutrition (for example, pregnancy induced hypertension, pre-eclampsia)w33 w42 have rarely been studied in relation to adult disease risk in humans. Evidence that hypertension during pregnancy in humans affects adult CVD...

Early life factors and intermediate heart disease risk factorsconditions

The associations between markers of fetal growth and intermediate risk factors are less consistent than evidence for morbidity and mortality. These include birth measures in relation to plasma concentrations of cholesterol, apolipoprotein B,w14 and fibrinogen,11 blood pressure,1213 and liability to impaired glucose tolerance and diabetes.14-16 Blood pressure has been suggested as one link between the intrauterine environment and the risk of CVD. Baker and colleagues studied Table 27.2 Summary...

Vascular smooth muscle cells

The necessary matrix proteins, in particular collagens and elastin, to repair the vessel. Indeed, expression of this repertoire of genes is essential for the formation of a fibrous cap over the lipid core of an atherosclerotic plaque. Since the fibrous cap separates the highly thrombogenic lipid rich core from circulating platelets and proteins of the coagulation cascade and confers structural stability to an atherosclerotic lesion, and since the VSMC is the only cell capable of synthesising...

Plaque disruption the healing process

The great majority of episodes of plaque disruption do not cause a major event such as infarction or death. Minor episodes of erosion or disruption are often clinically silent but do contribute to the episodic progression of coronary artery disease seen on sequential angiography. Thrombus will be removed by natural lysis to some extent and is also associated with passi- Plaques at risk of future thrombotic events are characterised by Large lipid cores (> 50 overall plaque volume) High...

Emerging valve disease

During the last 20 years, the medical community has witnessed the appearance of new forms of cardiac valve disease. There are three main sources of these modern types of valve involvement (a) new infectious diseases such as AIDS (b) drug related diseases resulting from the overuse of drugs that, in many cases, are specifically linked to problems only found in developed countries (for example, appetite suppressant drugs) and (c) new types of Figure 15.2. Evolution of different types of valve...

Glycoprotein IlbIIIa inhibitors

Despite the undoubted benefits of aspirin, patients with acute coronary syndromes nevertheless suffer important risks of subsequent cardiac events. In the presence of a potent thrombogenic stimulus, like that which follows rupture of an atheromatous plaque, the effects of aspirin may be overcome and platelet aggregation ensues. Cross linking of platelets occurs via the glycoprotein IIb IIIa receptor, with fibrinogen acting as the bridge.10 Large scale clinical trials have been conducted with...

Calcium entry blockers

Calcium antagonists act by inhibiting the slow inward current induced by the entry of extracellular calcium through the cell membrane. They lower myocardial oxygen demand and reduce arterial pressure and contractility. Some agents induce a reflex tachycardia and these are best administered in combination with a P adrenoceptor antagonist. In contrast, diltiazem and verapamil are suitable for patients who cannot tolerate a P blocker because they slow conduction through the atrioventricular node...

Ablation of VT after myocardial infarction

Most reported series included patients who had at least one mappable VT. Gonska and colleagues selected 72 patients who had a single clinical VT. RF ablation abolished the clinical VT in 74 of patients 60 of the total group remained free of spontaneous VT recurrences during follow up.6 Stevenson,7 Roth-man,8 and Strickberger9 and associates targeted multiple VTs for ablation in 108 patients with recurrent VT. An average of 3.6-4.7 different VTs were inducible per patient. All inducible...

Definition of the syndrome

Based upon trial data and prospective registries the following features define patients with an acute coronary syndrome Ischaemic chest pain (discomfort) at rest or on minimal exertion or emotion (2 x 5 minute episodes or 1 episode > 10 minutes). and Evidence of underlying coronary artery disease (at least one of the following) - ECG ST segment depression, T wave inversion or transient ST elevation - Enzyme elevation troponin I or T, creatine kinase (CK) or CK-MB - Evidence of coronary artery...

VT caused by nonischaemic cardiomyopathy

The mechanisms of sustained monomorphic VT in non-ischaemic cardiomyopathies (including idiopathic cardiomyopathy and valvar heart disease) are diverse. In a series of 26 patients with monomorphic VT the causes were scar related re-entry circuits in 62 of patients, an ectopic focus in 27 , and bundle branch re-entry in 19 .12 Ablation was successful for 60 of the scar related VTs and 86 of the VTs caused by focal automaticity. The difficulties in ablation of scar related VT are similar to those...

The sequence of thrombotic events

The thrombi which occur either in disruption or erosion circumstances are dynamic and evolve in stages. In disruption the initial stage occurs within the lipid core itself and is predominantly formed of platelets. As thrombus begins to protrude into the lumen the fibrin component increases, but any surface exposed to the blood in the lumen will be covered by activated platelets. While antegrade flow continues over this exposed thrombus, clumps of activated platelets are swept down into the...

Investigations

The ECG may show sinus tachycardia, focal or generalised abnormality, ST segment elevation, fascicular blocks or atrioventricular conduction disturbances. Although the ECG abnormalities are non-specific, the ECG has the virtue of drawing attention to the heart and leading to echocardiographic and other investigations. Echocardiography may reveal segmental or generalised wall motion abnormalities or a pericardial effusion. Echocardiography allows other causes of heart failure to be excluded but...

Biochemical factors

Enzymes released from cardiac myocytes have long been used as markers of injury to confirm myocardial infarction in patients presenting with acute coronary syndromes (fig 4.3). Creatine kinase and its more specific MB fraction remain widely used, but in recent years a number of novel biochemical markers (my-oglobin, troponin I and T) have been developed that are more sensitive and appear in the blood earlier after the onset of symptoms. Almost regardless of which biochemical marker is used,...

Left ventricular function

Left ventricular function is one of the major determinants of long term risk. There is now clear evidence that specific treatment with angiotensin converting enzyme (ACE) inhibitors (probably also P blockers) can reduce that risk, and coronary bypass surgery may be particularly beneficial when left ventricular dysfunction is associated with multivessel coronary artery disease. For many patients clinical criteria are sufficient to exclude significant left ventricular dysfunction, and an analysis...

Hormonal evidence related to fetal growth and later heart disease risk

Fetal growth is also affected by several hormones, growth factors, and genetic factors (fig 27.1). A recently proposed underlying mechanism, based mainly on animal studies, suggests that increased blood pressure in adult life is caused by increased exposure to corticosteroids during fetal life. This might result from reduced placental 11 P-hydroxysteroid dehydrogenase (11P-OHSD) activity or increased corticosteroid release secondary to disturbed nutrition.w9 w49-51 Increased exposure in turn...

The failing Fontan circulation and end stage pulmonary hypertension in older patients

When the chronically elevated systemic venous pressure associated with the Fontan operation (direct anastomosis of the right atrium to the pulmonary trunk) is poorly tolerated, creation of a small atrial septal defect may relieve the symptoms of high systemic venous pressure (albeit at the price of some degree of desaturation caused by right to left atrial shunting). Similarly, creation of a small atrial septal defect may reduce right atrial pressure and increase cardiac output in advanced...

Identification of high risk and low risk patients

There are two main components to the risk carried by an individual patient prior risk and acute ischaemic risk. Prior risk is determined by systemic risk factors such as age, diabetes, hypertension, smoking, heart failure, and previous infarction. Such factors influence the extent of underlying coronary artery disease and left ventricular dysfunction, and their impact may be revealed by echocardiography, stress testing, perfusion scanning or coronary angiography. Acute ischaemic risk is...

Applications of PET to cardiology

There has been much discussion about the dual roles of research and clinical PET. A number of centres have installed PET systems purely for clinical diagnosis, mainly in the determination of myocardial viability, but also for applications in oncology and neurology. Diagnostic testing of this kind is clearly derived from original work carried out at research establishments. The terms research and clinical should, therefore, be regarded as complementary. In the author's institution the balance...

Drug related diseases

Ergot alkaloid heart disease Methysergide and ergotamine are two classical drugs that are used in the prophylaxis and treatment of migraine headaches. Ergotamine is believed to relieve migraine by inducing vasoconstriction of the cerebrovascular bed, while methysergide achieves a similar eVect by its antiserotoninergic properties. They are ergot alkaloid derivatives, and both share a common chemical structure to the neurohormone serotonin. Serotonin is the agent responsible for valve disease in...

Acute coronary syndromes presentationclinical spectrum and management

Acute coronary syndromes define a spectrum of clinical manifestations of acute coronary artery disease. These extend from acute myocardial infarction through minimal myocardial injury to unstable angina. This spectrum shares common underlying patho-physiological mechanisms. The central features consist of fissuring or erosion of atheromatous plaque with superimposed platelet aggregation and thrombosis. This is complicated by microfragmentation and distal embolisation with alterations in...

Cardiac valve disease associated with the antiphospholipid syndrome

The antiphospholipid (aPL) syndrome is an entity characterised by vascular thrombosis with frequent heart involvement, particularly valvar lesions.19 The syndrome is caused by the appearance of circulating aPL antibodies, which are spontaneously acquired circulating immunoglobulins directed against negatively charged phospholipids. aPL antibodies were initially found in sera of patients with systemic lupus erythematosus. They have since been found occasionally in other connective tissue...

Ischaemic heart disease

Overt hypothyroidism is associated with hyper-lipidaemia and coronary artery disease. Approximately 3 of patients with longstanding hypothyroidism report angina, and a similar proportion report it during treatment with thy-roxine. In most patients the angina does not change, diminishes or disappears when thyrox-ine is introduced however, it may worsen and up to 40 of those patients who present with hypothyroidism and angina cannot tolerate full replacement treatment. Moreover, myocardial...

Dilated cardiomyopathy

The pathophysiological entity dilated cardiomyopathy (DCM) is heterogeneous with regard both to its pathogenesis and its morphology. Common to the whole group is a poorly contracting dilated left ventricle with a normal or reduced left ventricular wall thickness. The lack of an increase in left ventricular wall thickness tends to mask a significant increase in left ventricular mass. In the terminal stages thrombus may develop in the apices of both ventricles. The histological changes within the...

Which type of hyperthyroidism

Although there are features which help to distinguish between the two types of hyperthy-roidism (table 35.1), the differentiation may be diYcult and in some patients both mechanisms may be operating. In such circumstances it is sensible to institute a trial of carbimazole and to withdraw the drug after 3-4 months. If the patient remains euthyroid or becomes hypothyroid the diagnosis is likely to be type II hyperthyroidism evidence of persistent hyperthyroidism suggests a diagnosis of type I...

Amiodarone induced hypothyroidism

Amiodarone may cause hypothyroidism in patients with pre-existing Hashimoto's thyroiditis. However, the presence of a raised serum TSH concentration before or during treatment is not a contraindication to the use of amiodarone as the thyroid failure is readily treated with thyroxine. Amiodarone will induce hyper- or hypothyroidism in up to 20 of subjects, and thyroid dysfunction may persist for several months or develop for the first time after the drug has been stopped. Thyroid status should...

Proarrhythmia sodium channel block

The first drugs used to suppress cardiac arrhythmias were quinidine, procainamide, and lidocaine, which share the common property of sodium channel block. Modifications in these chemical structures led to compounds with more potent sodium channel blocking capability. Indeed agents with this property (flecainide, propafenone) are very effective in suppressing isolated ectopic beats and are among the drugs of choice for treatment of re-entrant supraventricular tachycardia in patients with no...

Myocardial infarction outside hospital

In the most recent study performed in the UK,1, 74 of 1589 deaths from acute coronary heart attacks in people under 75 years of age occurred outside hospital the proportion of out-of-hospital to total deaths varied inversely with age from 91 at age < 55 years to 67 at age 70-74 years (fig 6.1). Had the lives of 5 of potential victims of out-of-hospital sudden death not been saved by advanced life support given by ambulance staff, the proportion of out-of-hospital deaths to total deaths would...

Other possible models in the evolution of heart diseases and limitations of the studies

In Europe there are more than 20 large longitudinal studies in which the main focus has been or is to study prenatal or early life factors in relation to adult disease risk. Many of them are historical cohort studies, or data collection has started after birth retrospectively at various points of life. The most important historical cohort studies, from the point of view of the fetal origin hypothesis, are the Hertfordshire,4 14 Preston,12 21 and Sheffield8 studies, as well as the Helsinki27 and...

Biological programming a new theoretical model about the aetiology of heart disease

The dawn of modern epidemiology came after the second world war, first with ecological studies comparing CVD incidence and mortality, and subsequently multicentre cross sectional and follow up studies on CVD.w3 The studies showed that populations with high CVD mortality have high cholesterol and high blood pressure, and that smoking and obesity are common among these populations.4 This led to the lifestyle model in understanding the aetiology of chronic diseases, where the key issues are health...

Risk stratification

SPECT perfusion imaging is also useful for the purpose of non-invasive risk stratification to identify patients who have the greatest risk for subsequent death and myocardial infarction. High risk (> 3 annual mortality) features on stress SPECT perfusion imaging Post-stress ejection fraction < 35 (technetium-99m) Stress induced large perfusion defect Stress induced multiple perfusion defects of moderate size Large, fixed perfusion defect with left ventricular dilatation or increased lung...

Acute myocardial infarction

It is difficult now to perceive why coronary thrombosis was regarded 25 years ago as an inconstant and irrelevant consequence of acute infarction rather than its prime cause. Once angiography was carried out soon after the onset of infarction, and it was realised that the subtending artery was totally blocked but spontaneously reopened with time in many cases (and that this reopening was accelerated by fibrinolytic treatment), thrombosis was seen as a major causal factor in occlusion. Suddenly...

Over replacement with thyroxine

Central Hypothyroidism

There is some concern that administering thy-roxine in a dose which suppresses serum TSH may provoke significant cardiovascular problems, including abnormal ventricular diastolic relaxation, a reduced exercise capacity, an that a suppressed serum TSH concentration in a patient taking thyroxine in whom serum T3 is unequivocally normal is a risk factor for atrial fibrillation. Figure 35.3. Sequential chest x rays from a patient with longstanding hypothyroidism that was complicated by congestive...

Degenerative valve disease

Although there has been a dramatic reduction in rheumatic valve disease in the industrialised countries over the past 30 years, there has not been a similar reduction in valve surgery. This is because the types of patients being referred for surgery have changed. The significant increase in life expectancy in developed countries partly accounts for this change in aetiology, especially in aortic valve disease. In one surgical series over a five year period (from 1981 to 1985), it was found that...

Left ventricular restoration

Patients with large left ventricular aneurysms gain symptomatic relief from simple linear aneurysmectomy. So called ventricular restoration has recently extended from scarred paradoxical segments to akinetic areas which were not previously thought suitable for surgery.13 The goal of surgical reversal of remodelling is to exclude the infarcted septum and free wall and reshape the left ventricle from globular to elliptical without critically reducing Table 11.3 Decision making in the surgery of...

The atherosclerotic plaque

Atherosclerosis begins as a subendothelial accumulation of lipid laden, monocyte derived foam cells and associated T cells which form a non-stenotic fatty streak. With progression, the lesions take the form of an acellular core of cholesterol esters bounded by an endothelial-ised fibrous cap containing vascular smooth muscle cells (VSMC) and inflammatory cells, predominantly macrophages with some T cells and mast cells, which tend to accumulate at the shoulder regions of the plaque. Also...

Transvenous endocardial pacing

There are arguments in favour of and against all the major venous access sites (internal and external jugular, subclavian, brachial, femoral) each is associated with particular problems including lead stability, infection, haemorrhage, pneumothorax, patient discomfort, etc. As this procedure is often performed in emergency acute situations by relatively junior staff, the choice of route is often dictated by individual experience. Other considerations should include length of time that the...

VT related to regions of scar

The majority of sustained monomorphic VTs are caused by re-entry involving a region of ventricular scar. The scar is most commonly caused by an old myocardial infarction, but arrhythmogenic right ventricular dysplasia, sarcoidosis, Chagas' disease, other non-ischaemic cardiomyopathies and surgical ventricular incisions for repair of tetralogy of Fallot, other congenital heart diseases, or ventricular volume reduction surgery (Batista procedure) can also cause scar related re-entry. Dense...

Other causes of acute myocarditis

Lyme disease caused by Borrelia burgdorferi, a tick borne organism carried by deer, may cause an acute myocarditis, typically with a long PR interval as occurs with acute rheumatic fever. Left ventricular dysfunction is usually transient but the organism has been cultured from endomyocardial biopsy material in a patient with a dilated cardiomyopathy. Chagas' disease, common in rural parts of Central and South America, results from infection by Trypanosoma cruzi. Although best known as a cause...

Acute myocardial infarction in hospital

Course no attempt at distinction between infarction and electrical death is possible in purely epidemiological studies. Yet another problem in identification of the natural history of acute myocardial infarction is that fully 25 of non-fatal infarctions are silent.8 Silent infarction can be detected only when a subject is seen more than once at annual intervals or longer, and an ECG performed on the second occasion shows new pathological Q waves. Most clinicians can remember such cases, but an...

The balance of atherosclerosis

Atherosclerosis is a dynamic balance between the destructive influence of inflammatory cells and the reactive, stabilising effects of VSMCs. The balance is biased in favour of plaque rupture by factors such as high low density lipoprotein LDL cholesterol, lipid peroxidation and, probably, genetic variability in the inflammatory molecules involved. For example, there is a correlation between plaque progression and a polymorphism in the stromelysin-1 gene promoter. Also, it is entirely plausible...