Cardiology Opinion Research Articles

Primary Prevention of Sudden Cardiac Death

The trouble with sudden cardiac death (SCD) is just that—it is sudden and individually unpredictable. Recent data from the Centers for Disease Control showed that SCD accounted for >460 000 deaths, or about 63% of deaths due to cardiac disease, in 1999.1 Typically, a cardiac arrest results from sustained ventricular tachycardia (VT) or ventricular fibrillation that progresses to death if effective resuscitative efforts are not started within several minutes of the arrest.2 It is not surprising that the overall survival rate of patients with out-of-hospital cardiac arrest in the United States is low, estimated to be <5%.3 Although more widespread use of automated external defibrillators could lead to a reduction in SCD,3 it is unrealistic to expect too much from this technology, especially because most cardiac arrests either are unwitnessed or occur in a location without ready access to an automated external defibrillator. The epidemic proportions of SCD have led to decades of research and randomized clinical trials designed to predict which individuals are at risk of SCD and to determine what methods prevent it. See p 1082 Coronary artery disease (CAD) causes ≈70% of SCD,1 and most clinical trials have evaluated this patient population. The emphasis of this Focused Perspective is on antiarrhythmic drug and device trials, but the reader should remember that selective use of β-adrenergic–blockers and angiotensin-converting enzyme inhibitors has reduced SCD.2,4,5 It has been known for decades that patients at highest risk for SCD after myocardial infarction (MI) have substantial left ventricular dysfunction, frequent premature ventricular complexes (PVCs) or nonsustained VT, or both conditions.2 Early efforts to prevent SCD employed the PVC suppression method. The Cardiac Arrhythmia Suppression Trial (CAST) was a randomized, placebo-controlled study that tested the hypothesis that PVC suppression after MI would reduce arrhythmic death.6 …

Preoperative cardiac assessment for patients with infrarenal abdominal aortic aneurysms: a survey of current practice by vascular surgeons in New South Wales and Australian Capital Territory.

The reported mortality rate following open elective repair of abdominal aortic aneurysm (AAA) varies between 0 and 12%. Much of the mortality and major morbidity is caused by cardiac events. The evidence regarding best practice for cardiac assessment and optimization of this patient group is unclear. The aim of the present study was to evaluate current practice of cardiac risk factor assessment by vascular surgeons in New South Wales (NSW) and Australian Capital Territory (ACT) for patients undergoing open elective repair of infrarenal AAA. A postal questionnaire was sent to 46 surgeons in NSW and ACT identified as expressing a principal or major interest in vascular surgery. If no response was received within 3 weeks, a second questionnaire was sent and if no response was received after the second mailing, a telephone survey of non-responders was conducted. Data were collated regarding the importance of risk factors elicited by clinical history, preoperative investigation, referral for cardiological opinion, use of perioperative beta-blockade and the timing of aortic surgery in relation to coronary artery revascularization and acute myocardial infarction. The overall response rate was 87% (40/46) and the median (range) response time was 14 (4-109) days. Only 22 of 40 and 23 of 40 surgeons consider diabetes mellitus or renal impairment, respectively, to be important when assessing cardiac risk and 34 of 40 surgeons do not employ a validated risk index in preoperative assessment. Sixteen of 40 surgeons refer all patients needing AAA repair to a cardiologist, while 24 of 40 would initiate cardiac investigations themselves (either stress electrocardiography, scintigraphy or echocardiography). Seventeen surgeons always or usually commenced perioperative beta-blockade with wide variations in the commencement (1 to > 28 days preoperatively) and duration (< 1 week to > 28 days postoperatively) of treatment. The timing of AAA repair following coronary revascularization ranged from < 1 week to 6 months and delay in surgical repair of AAA following myocardial infarction ranged from < 1 week to > 6 months. Preoperative assessment of cardiac risk in patients for repair of AAA lacks consensus among vascular surgeons in NSW and ACT. The diversity of clinical practice may rest with the paucity of prospective trials published in the medical literature or the influence of local institutional facilities.

ApoA-II Versus ApoA-I

Apolipoprotein A-I (apoA-I), the major protein of HDL, is probably among the most intensively studied of all proteins. It functions in HDL assembly, in the removal of excess cholesterol from cells, and in the transport of cholesterol from peripheral tissues to the liver, a process known as “reverse cholesterol transport.” It is a cofactor for lecithin:cholesterol acyl transferase (LCAT), the enzyme responsible for cholesterol esterification in HDL, and it stabilizes certain antioxidant enzymes, such as serum paraoxonase, that are carried on HDL.1,2 Rare null mutations of apoA-I in human populations are associated with early coronary heart disease,3 and overexpression of apoA-I in transgenic mice protects against atherogenesis.4 An exciting recent development was the 4-angstrom-resolution x-ray structure for the helical part of apoA-I, encompassing residues 44 to 243 (reviewed by Segrest et al5). See page 1977 In contrast, apolipoprotein A-II (apoA-II), the second most abundant protein of HDL, has no known function, and it has been the subject of few detailed studies. Its presence in HDL has been reported to decrease,6 or have no influence on, cholesterol efflux from cells,7,8 nor is it a cofactor for any known enzyme. Rare individuals lacking apoA-II appear to have normal plasma lipids.9 In fact, all of the known effects of apoA-II are deleterious. In studies with mice and humans, apoA-II levels have been associated with increased susceptibility to atherosclerosis,10–13 increased free fatty acid levels,14,15 increased body fat,15,16 and increased insulin resistance.15,17 Undoubtedly, apoA-II has some unknown beneficial functions, possibly related to fatty acid metabolism or host defense. In this issue of Arteriosclerosis, Thrombosis, and Vascular Biology , …

Atrophy of Myocardium and Its Myocytes by Left Ventricular Assist Device

To the Editor: Dipla and coworkers1 believe that their data support the notion that a temporary left ventricular assist device (LVAD) obviates the need of cardiac transplantation of the failing heart. Barry2 supports this notion. The LVAD is a double-edged sword. The beneficial effects of this device are well known. Its action ensures sufficient nutrition to the peripheral tissues so that they can recover from starvation and also eliminates or decreases the harmful effects of the increased catabolic products produced by the starved tissues. Harmful effects of the LVAD are due to the rapid, profound decrease of cardiac work (contraction) that leads to atrophy of the myocardium and its myocytes. An excellent description of the morphological changes that occur in myocardial atrophy is present in Bargmann and Doerr’s textbook.3 Modern textbooks of medicine and cardiology ignore this subject, with the exception of Braunwald’s,4 which devotes a single sentence published in fine print to it. This is as …

Bibliography Current World Literature

This Bibliography is Produced in Association with Current Opinion in Cardiology (Rapid Science Publishers, USA). This issue consists of literature scanned during June, July, August and September 1997

Current Opinion in Cardiology

Current Opinion in Cardiology

Current Opinion in Cardiology

Current Opinion in Cardiology

Minimally invasive heart surgery. Executive Committee of the Council on Cardio-Thoracic and Vascular Surgery.

Limited access or minimally invasive coronary artery surgery is being evaluated in numerous North American medical centers. The purposes of this report are to (1) describe the techniques, (2) examine progress in this new field, (3) comment on the potential of these approaches, and (4) put into perspective the expected goals of minimally invasive coronary surgery, given the proven long-term results achieved with traditional techniques (sternotomy and cardiopulmonary bypass). Minimally invasive coronary artery bypass is performed using one of two approaches: (1) a series of small holes or “ports” in the chest (referred to as PACAB, PortCAB, or port-access coronary artery bypass) or (2) a combination of ports and a small incision directly over the coronary artery to be bypassed (referred to as MIDCAB or minimally invasive coronary artery bypass). As in standard coronary artery bypass graft surgery (CABG), anesthesia is required. PACAB is currently used only by investigators at a few university centers. In this method, cardiopulmonary bypass is performed using the femoral vessels. The heart is stopped and the bypasses are performed using instruments passed through the ports, with or without a small additional chest incision. As with abdominal laparoscopic surgery, the cardiac …

Recent progress in digital image formatting and current trends in computers: their role in digital image storage and telemedicine. Commentary.

This section of Current Opinion in Cardiology is dedicated to recent progress in imaging and echocardiography. Two trends apparent from the five articles in this symposium are the increasing importance of quantitation in cardiovascular imaging and the emergence of new modalities for assessing cardiac structure and function. The exploding volume of imaging data available to the practicing cardiologist has made it increasingly difficult to organize and manage this information in order to obtain an integrated picture of the patient's clinical status. Fortunately, we are also in the midst of a revolution in digital image storage and transmission, which will ease the task of organizing multimodal clinical images and avoiding unnecessary duplication of tests. This commentary reviews important progress in the past year in the development of standardized image formats as well as trends in better computer performance. In echocardiography, ultrasound loops can be stored with calibration data (spatial, temporal, and velocity) to facilitate automated application of some of the new quantitative algorithms outlined by Frank Flachskampf in his article (pp 634-639) [2]. Spatial localizing information can also be stored with the echocardiographic images to facilitate three- and four-dimensional reconstruction of these data. In cineangiography, the DICOM standard codifies methods for storing view orientation, interventional device identification, and the details of contrast administration, facilitating the threedimensional reconstruction and physiological analysis of catheterization data [3]. Finally, in the nuclear cardiology standard, entire protocols involving multiple radioisotopes may be encoded within a single digital study, facilitating the automated display and analysis, for instance, of such data as positron-emission tomography perfusion and metabolic imaging.

Current Opinion in CARDIOLOGY

Current Opinion in CARDIOLOGY

Editorial overview

Alton Ochsner Medical Foundation, New Orleans, Louisiana, USA Current Opinion in Cardiology 1995,10:443–444 Edward D. Frohlich, MD, Vice President for Academic Affairs, Alton Ochsner Medical Foundation, 1516 Jefferson Highway, New Orleans, LA 70121, USA.

Recent advances in the understanding and management of stable and unstable angina pectoris and asymptomatic myocardial ischemia

Angina continues to be a leading cause of morbidity and mortality in the Western world. While the clinical identification of angina occurred over two centuries ago, our understanding of the pathophysiology of the anginal syndromes continues to increase rapidly, as does our understanding of the triggers of angina and its prognosis. These insights have allowed us to tailor therapy and diagnostic strategy more accurately to reverse the pathophysiological defect. As our understanding grows, our ability to prevent the deleterious outcomes associated with angina will increase.

New technologies in interventional cardiology.

The limitations of balloon angioplasty have led to the introduction of new devices designed to improve the short- and long-term efficacy of percutaneous revascularization techniques. Preliminary single-operator experience and registry data have suggested that these devices may be useful in particular anatomical situations. Last year saw the beginning of the next phase of device assessment, the randomized study, directly comparing the new devices with coronary angioplasty either in the total angioplasty patient population or in selected subgroups. Two major randomized studies, the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) and the Canadian Coronary Atherectomy Trial (CCAT), directly compared directional coronary atherectomy with balloon angioplasty and suggested that coronary atherectomy offers no particular advantage over balloon angioplasty. This year will see the publication of the Belgium Netherlands Stent (BENESTENT) and Stent Restenosis Study (STRESS) randomized trials, which compared coronary stents with balloon angioplasty; further studies comparing balloon angioplasty with other devices are currently under way. We are now entering a new era where randomized studies will directly assess the safety and efficacy of the new devices compared with balloon angioplasty and demonstrate, in a scientific manner, the validity (or otherwise) of their superiority over balloon angioplasty.

CAROTID SINUS HYPERSENSITIVITY IN PATIENTS REFERRED WITH POSSIBLE EPILEPSY

SUMMARY Four patients with recurrent transient loss of consciousness, all of whom had previously undergone extensive non‐invasive cardiological investigations, were referred for neurological opinion. All were found to exhibit a resting bradycardia and a cardioinhibitory response to carotid sinus stimulation. All were referred for cardiological opinion but only two patients were considered by their respective cardiologists to warrant pacemaker implantation. Those who did not receive a pacemaker continue to suffer from their symptoms. The clinical management of these patients highlights an apparent divergence of opinion amongst cardiologists on the treatment of carotid sinus hypersensitivity and emphasises that, unless the ECG and blood pressure responses to carotid sinus stimulation are observed in patients with histories of unexplained episodes of altered consciousness, carotid sinus hypersensitivity will be missed as a possible cause of symptoms. The presence of unexplained bradycardia may suggest carotid sinus hypersensitivity.

Neurological or Cardiological Assessment of Transient Altered Consciousness?

Cardiac arrhythmias are a recognized cause of transient alteration of consciousness and unless suspected, a cardiac aetiology for apparent neurological symptoms may be overlooked. We retrospectively assessed the variation in the investigations of 122 patients who were referred to our hospital over a twelve month period for assessment of transient alteration of consciousness and we attempted to identify any factors which might have influenced the clinical outcome for these individuals. Eighteen patients were initially referred for cardiological opinion and 104 for neurological assessment. Sixty-one patients presented with syncope, 43 with seizures, and 18 with presyncope. A baseline electroencephalogram (EEG) was obtained in 104 (85%) and 65 (53%) were also subjected to a stress EEG. Cerebral dysrhythmia was documented in 14 patients. A standard electrocardiogram (ECG) was recorded in only 71 (58%) and sinus bradycardia (heart rate < 60/min) was observed in 34. Twenty-four hour (Holter) ECGs were recorded in only 58 (48%). Ventricular pauses (at least 1.84 seconds) and/or profound bradycardia (heart rate < 40/min) occurred during waking hours in 10 patients and were more likely to be detected in individuals who also exhibited bradycardia on standard ECG (8 patients) (p < 0.05). After six months, 35 (29%) of the 122 patients still lacked a diagnosis and although cerebral dysrhythmia had been diagnosed with equal frequency in the bradycardia and non-bradycardia groups, 21 (62%) of those with bradycardia were still symptomatic compared with 11 (30%) of the non-bradycardia group (p < 0.02). Our findings indicate that, at present, investigation of patients with transient altered consciousness lacks a coordinated approach and bradycardia may influence the diagnosis and morbidity of these individuals. We suggest that greater attention should be paid to possible cardiac causes of transient altered consciousness and that only under joint direction of a cardiologist and a neurologist can efficient and thorough investigation of these patients be realised.

Editorial overview

University of Alabama Medical Center, Birmingham, Alabama, USA Current Opinion in Cardiology 1993, 8:553–556

Editorial overview

The Cleveland Clinic Foundation, Cleveland, Ohio, USA Current Opinion in Cardiology 1993, 8:245–246

Current Opinion in CARDIOLOGY

Current Opinion in CARDIOLOGY

Pediatrics

Yale University School of Medicine, New Haven, Connecticut, USA Current Opinion in Cardiology 1991, 6:79–80

Aortic dissection and coarctation.

The Cleveland Clinic Foundation, Cleveland, Ohio, USA Current Opinion in Cardiology 1990, 5:649–654