Catheter ablation for atrial fibrillation: who, why and does it work?

Atrial fibrillation (AF) is the most common arrhythmia. For many years, treatment was predominantly pharmacological. The identification of signals from the pulmonary veins as critical to AF in many patients led to catheter ablation targeting these signals. Catheter ablation is more effective than antiarrhythmic drugs at restoring sinus rhythm, and may improve mortality, morbidity and quality of life in patients with symptomatic AF. There is evidence to suggest that catheter ablation would be even more beneficial if undertaken earlier in the disease process. Cost effectiveness of catheter ablation remains under assessment, but it does meet the NICE definition of cost efficacy and the figure improves as stroke risk rises. It is true that long-term data are lacking. However, until results of current long-term studies become available, ablation will continue to be reserved predominantly for patients with drug-refractory, symptomatic AF.

Radiofrequency ablation of cardiac arrhythmias: past, present and future.

The treatment of cardiac arrhythmias has been revolutionized by the ability to definitively treat many patients with radiofrequency catheter ablation, rather than requiring lifelong medication. This review covers the history of how this has developed and the methods used currently and explores what the future holds for this rapidly evolving branch of Cardiology.

Cardiorespiratory symptoms during pregnancy--not always pulmonary embolism.

We describe a case of sudden onset severe cardiorespiratory compromise in a parturient at 36 weeks' gestation. She received treatment for infection, pulmonary oedema and pulmonary embolism before a diagnosis of aortic dissection was made. Successful repair was undertaken following caesarean section. We discuss the difficulties of diagnosis of cardiorespiratory symptoms and the potential hazards of instituting therapy before a definitive diagnosis is reached. The value of a multidisciplinary team approach and the use of portable echocardiography in the investigation of both pulmonary embolism and cardiac disease are emphasised.

Usage of troponin in the real world: a lesson for the introduction of biochemical assays.

BACKGROUND: Studies have demonstrated economic and clinical effectiveness using troponin as a risk stratification tool in chest pain patients. Those with a positive result are investigated invasively, whilst those with a negative result and ECG are promptly mobilized, facilitating discharge. AIM: To determine whether our use of troponin I (cTnI) in routine clinical practice conforms to ideal standards. DESIGN: Audit study. METHODS: Data were collected from 93 laboratory request forms for cTnI measurement on 72 patients with matched available patient records. RESULTS: Eighty requests had no information regarding timing of blood sample in relation to the clinical event; 39% gave no clinical indication. Only 71% of results were available within 12 h. An admission diagnosis of acute coronary syndrome (ACS) was made in 25%. Fifteen had typical cardiac chest pain with a negative cTnI: 6 of these had an exercise treadmill test before discharge. Nine had a positive cTnI, but only two had coronary angiography. Of patients with negative cTnI and possible ACS, 84% were in hospital for >4 days. DISCUSSION: The introduction of troponin assays into widespread use requires careful assessment. cTnI requests and subsequent patient management remain below expected standards. Ideally, the laboratory should provide an accurate result within a reasonable time frame, while physicians need to request cTnI at a suitable time-point and use the result appropriately. Lessons from the introduction of cTnI measurement may be useful for the introduction of future new tests in other areas of cardiology and medicine.

Infarct zone viability influences ventricular remodelling after late recanalisation of an occluded infarct related artery.

OBJECTIVE: To investigate the influence of infarct zone viability on remodelling after late recanalisation of an occluded infarct related artery. METHODS: A subgroup of 26 volunteers from TOAT (the open artery trial) underwent dobutamine stress cardiovascular magnetic resonance at baseline to assess the amount of viable myocardium present with follow up to assess remodelling at one year. TOAT studied patients with left ventricular dysfunction after anterior myocardial infarction (MI) associated with isolated proximal occlusion of the left anterior descending coronary artery with randomisation to percutaneous coronary intervention (PCI) with stent at 3.6 weeks after MI (PCI group) or to medical treatment alone (medical group). RESULTS: In the PCI group there was a significant relation between the number of viable segments within the infarct zone and improvement in end systolic volume index (-7.7 ml/m2, p = 0.02) and increased ejection fraction (4.1%, p = 0.03). The relation between viability and improvements in end diastolic volume index (-8.8 ml/m2, p = 0.08) and mass index (-6.3 g/m2, p = 0.01) did not reach significance (p = 0.27 and p = 0.8, respectively). In the medical group, there was no significant relation between the number of viable segments in the infarct zone and the subsequent changes in end diastolic (p = 0.84) and end systolic volume indices (p = 0.34), ejection fraction (p = 0.1), and mass index (p = 0.24). CONCLUSION: The extent of viable myocardium in the infarct zone is related to improvements in left ventricular remodelling in patients who undergo late recanalisation of an occluded infarct related artery.

Communicable diseases monitored by disease surveillance in Kottayam district, Kerala state, India.

BACKGROUND & OBJECTIVES: A disease surveillance model developed in the North Arcot district, Tamil Nadu, was found to be practical, efficient, inexpensive and useful for public health action to monitor the success of ongoing interventions and to detect and intercept outbreaks. It was centred in the private (voluntary) sector with full co-operation and participation by the government sector. As Kerala state wanted to replicate this model in all districts, one district was chosen to pilot test it centred within the existing district public health system, soliciting participation from the private sector. A two-year (1999-2001) performance of this model is presented. METHODS: After elaborate preparations including the selection of 14 diseases to be reported and training of doctors in the private sector health care institutions and doctors and paramedical staff in all government health centres and hospitals, printed post cards were widely distributed. The business reply system was used so as to avoid handling postage stamps. Cards were received by the nodal officer in the district public health office and checked on a daily basis to detect disease prevalence and evidence of clustering in time and space. Swift action was taken on detecting case clustering. A monthly bulletin containing disease summaries and other useful information was freely distributed to all reporting centres. RESULTS: On an average, just over 100 disease reports were received every month. The most frequently reported diseases were, in the descending order, leptospirosis, acute dysentery, typhoid fever and acute hepatitis. Among vaccine-preventable childhood diseases, only measles was reported, but no diphtheria, tetanus or whooping cough. Several outbreaks were detected early and interventions applied to intercept them. The most striking example was that of cholera, the occurrence of which was detected swiftly for instituting highly successful control measures. INTERPRETATION & CONCLUSION: The district level disease surveillance system centred in the government public health system has been highly successful. Disease surveillance was responsible for the government to obtain information on the prevalence of leptospirosis in the district. The reports enabled the public health officers to detect disease-clustering as the early signals of outbreaks and to take quick remedial measures.

Effects of carvedilol on left ventricular remodelling in chronic stable heart failure: a cardiovascular magnetic resonance study.

BACKGROUND: The ability of beta blockers to improve left ventricular function has been demonstrated, but data on the effects on cardiac remodelling are limited. OBJECTIVE: To investigate, using cardiovascular magnetic resonance (CMR), the effects of carvedilol on left ventricular remodelling in patients with chronic stable heart failure and left ventricular systolic dysfunction caused by coronary artery disease. DESIGN: Randomised, double blind, placebo controlled study. SETTING: Chronic stable heart failure. PATIENTS AND INTERVENTION: 34 patients with chronic stable heart failure and left ventricular systolic function taking part in the CHRISTMAS trial (double blind carvedilol v placebo) underwent CMR before randomisation and after six months of treatment. MAIN OUTCOME MEASURE: Left ventricular remodelling at six months. RESULTS: The carvedilol and placebo groups were well balanced at baseline, with no significant intergroup differences. Over the study period, there was a significant reduction in end systolic volume index (ESV(I)) and end diastolic volume index (EDV(I)) between the carvedilol and the placebo group (carvedilol -9 v placebo +3 ml/m2, p = 0.0004; carvedilol -8 v placebo 0 ml/m2, p = 0.05). The ejection fraction increased significantly between the groups (carvedilol +3% v placebo -2%, p = 0.003). CONCLUSIONS: Treatment of chronic stable heart failure with carvedilol results in significant improvement in left ventricular volumes and function. These effects might contribute to the benefits of carvedilol on mortality and morbidity in patients with chronic heart failure.

Lichen myxoedematosus with associated cardiac abnormalities.

We describe a 42-year-old woman who developed lichen myxoedematosus. Twenty years after the onset of the disease she became breathless and hypertensive, and an echocardiogram showed a mass on the mitral valve, which was thought to be a mucin deposit. Her hypertension was resistant to treatment with combination antihypertensives. To our knowledge, this is the first report to link lichen myxoedematosus with a valvular mucinous mass. This case also demonstrates the slow clinical progression of the disease over 20 years.

The role of cardiovascular magnetic resonance in heart failure.

Cardiovascular Magnetic Resonance (CMR) is an accepted gold standard for non-invasive, accurate, and reproducible assessment of cardiac mass and function. The interest in its use for viability, myocardial perfusion and coronary artery imaging is also widespread and growing rapidly as the hardware and expertise becomes available in more centres, and the scans themselves become more cost effective. In patients with heart failure, accurate and reproducible serial assessment of remodelling is of prognostic importance and the lack of exposure to ionizing radiation is helpful. The concept of an integrated approach to heart failure and its complications using CMR is fast becoming a reality, and this will be tested widely in the coming few years, with the new generation of dedicated CMR scanners.

Left ventricular quantification in heart failure by cardiovascular MR using prospective respiratory navigator gating: comparison with breath-hold acquisition.

Cardiovascular magnetic resonance (CMR) is the reference standard for the assessment of cardiac function. Faster sequences, such as breath-hold (BH) fast low-angle shot, have made CMR more clinically acceptable and cost effective. In a significantly large patient group, however, holding their breath is difficult, resulting in poor-quality images. We compared prospective navigator-echo respiratory gating (NE), which allows image acquisition during free breathing, and BH imaging in 14 patients with heart failure and 10 normal volunteers. There was good agreement between both NE and BH volumes, mass, and ejection fraction. The image quality of both NE basal and apical slices was significantly better than the corresponding BH slices in both the heart failure (P < 0.01) and normal groups (P < 0.05). The NE image acquisition was more time efficient than the BH acquisition in the heart failure group (P < 0. 01), with no difference in the normal group (P = 0.2). Thus, prospective navigator-echo gating, previously only described in coronary artery imaging, can be used in the assessment of cardiac function. It is particularly useful in patients who find it difficult to hold their breath in whom NE provides good-quality, time-efficient images.

Compatible volumetric 3-D TV systems: a proposal.

Three types of 3-D TV system compatible with existing 2-D TV systems are proposed. These systems are not based on stereoscopic image techniques and do not impose any constraints on the viewer for 3-D perception. The first system makes use of the existing conventional color TV system for development of a 3-D TV system. The second system is based on the present monochromatic TV system. The third system depends on a light-emitting diode tank for 3-D display. To prove the validity of these systems a simulated experiment is demonstrated for the reproduction of a 3-D image using still photographs. All these systems are compared for their relative merits and demerits.