Atrial fibrillation diagnosis

Atrial fibrillation is commonly associated with heart failure, and the prevalence of atrial fibrillation is related to the severity of heart failure, with less than 5% affected with very mild heart failure to nearly 50% affected with advanced heart failure [66]. Heart failure and atrial fibrillation are both common cardiovascular disorders and share the same demographic risk factors, including age, history of hypertension, prior myocardial infarction, and valvular heart disease [67, 68]. Further, the incidence of heart failure increases dramatically after the diagnosis of atrial fibrillation [69]. Progression of LV dysfunction can clearly be associated with rapid ventricular rates [70-76]. Conversely, conversion to normal sinus rhythm or control of ventricular response in atrial fibrillation can improve LV function [71-74, 77]. Accordingly, rate control becomes very important in patients with heart failure and dilated cardiomyopathy, and likely even more so when ischemia from rapid rates complicate the patient s course. 

Adenosine is the treatment of choice for diagnosis and reversal of supraventricular arrhythmias. Verapamil is an alternative for the management of narrow complex tachycardias. Amiodarone is the most effective drug at reversing atrial fibrillation, and in prevention of ventricular arrhythmias, but has several adverse effects. 

Heparin is an anticoagulant that inhibits reactions that lead to clotting. It is indicated in prophylaxis and treatment of venous thrombosis and its extensions, pulmonary embolism (PE), peripheral arterial embolism, and atrial fibrillation with embolization diagnosis and treatment of acute and chronic consumption coagulopathies (DIC) and prevention of postoperative deep venous thrombosis. 

Cardiovascular The use of glucocorticoids is associated with increased risks of myocardial infarction, stroke, and heart failure, but data are limited on the risk of atrial fibrillation and atrial flutter. In a case-control study patients with a first hospital diagnosis of atrial fibrillation or flutter were identified in Northern Denmark p "]. For each case 10 population controls matched by age and sex were selected. 

Fig. 16.11 Ventricular pacing in the setting of atrial fibrillation. The top strip illustrates atrial fibrillation with ventricular pacing in VVI mode. In the bottom strip, the mode of function is VDD mode, in which sensed atrial signals trigger ventricular stimulus outputs. Atrial fibriUatory impulses are sensed, leading to ventricular pacing at a rate of 100 per minute note the increased QRS duration due to rate-dependent intraventricular conduction delay. Based on this ECG, an erroneous diagnosis of hyperkalemia could be entertained.

A patient taking amiodarone for atrial fibrillation developed hyperthyroxinemia, which led to a diagnosis of thyroid hormone resistance syndrome [3(r]. Although thyroid hormone resistance is not a complication of amiodarone treatment, hyperproduction of hormone, accompanied by high concentrations of thyroid hormone without TSH suppression, is a rare genetic disorder that is worth being aware of. 

A 69-year-old woman presented with sudden onset of left facial drop, dizziness, slurred speech and impaired balance [35 ]. History included paroxysmal atrial fibrillation and a sigmoid diverticular abscess treated with ciprofloxacin and metronidazole. Cranial CT angiography and MRI showed no signs of ischaemia or haemorrhage but demonstrated symmetrically distributed lesions in the cerebellar dentate nuclei. A diagnosis of metronidazole-induced encephalopatiiy was suspected and the drug withdrawn. Patient made uneventful recovery. 

Gastrointestinal An 80-year-old woman presented as an emergency case after 2 weeks of vomiting, abdominal pain and diarrhoea. She had commenced warfarin use 3 weeks prior for paroxysmal atrial fibrillation. An X-ray revealed concentric mural thickening of the proximal jejunum, extending distally from the duodenal-jejxmal flexure and the provisional diagnosis was a spontaneous intramural jejunal haematoma. Warfarin was withheld and with Vitamin K, 3-factor prothrombin complex concentrate and fresh frozen plasma treatment, she recovered and tire abnormality resolved [3 ]. 

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