Left atrial abnormality

Left atrial abnormality, also known as P. mitrale, as it is commonly associated with mitral valve disease (Fig. 5.6). Left atrial abnormality is seen on an ECG as broad, notched/bifld M shaped P waves. These P waves are often greater than 2.5 mm in width (see Fig. 5.7). This is best seen in leads II and Vi. Another indicator is seen in lead Vi where there is a negative deflection below the base line of more than 1 mm and a width greater than 1 m (Fig. 5.8). 

Bilateral atrial abnormality refers to an abnormality that affects both atria (Fig. 5.9). This can be detected by the combination of indicators for both right and left atrial abnormality, present on the same ECG. Table 5.1 snmmarises some of the key P wave changes present in right, left and bilateral atrial abnormality. 

S wave in Vi +R wave in Vg >35 mm in height Accompanied left atrial abnormality... 

Ql. Left atrial abnormality is also sometimes known as ... 

Sakurai K, et al, Left atrial appendage function and abnormal hypercoagulability in patients with atrial flutter, Chest 2003 ... 

In patients with coronary artery disease, electrocardiographic evidence of abnormal P wave, similar to left atrial enlargement, is a marker of poor left ventricular function andprognosis (Rios, 1977). 

Changes in the size and shape of the P wave can point towards an atrial abnormality, which may be caused by right or left atrial enlargement (Figs. 5.4 and 5.6 respectively) or more rarely a conduction delay. Additional evidence for the presence of an atrial abnormality, enlargement, dilation or hypertrophy is the coexistence of a ventricular hypertrophy. 

Right ventricular hypertrophy (Fig. 5.12) is less common than left ventricular hypertrophy. RVH is often accompanied by right atrial abnormality and tall R waves in lead Vi (height of R wave > depth of S wave), and right axis deviation. In more severe cases ST segment depression and T wave inversion, indicating strain pattern can sometimes be seen (Fig. 5.13). 

The IV administration of propafenone is accompanied by an increase in right atrial, pulmonary arterial, and pulmonary artery wedge pressures in addition to an increase in vascular resistance and a decrease in the cardiac index. A significant decrease in ejection fraction may be observed in patients with preexisting left ventricular dysfunction. In the absence of cardiac abnormalities, propafenone has no significant effects on cardiac function. 

Q13 Arterial emboli, which can block blood vessels and cause ischaemia or infarction in the tissues they affect, tend to originate in the left heart and are associated with valvular disease and dysrhythmias. Mitral stenosis is associated with abnormal atrial rhythm, particularly atrial fibrillation. Fibrillation and other rhythm abnormalities in the atria favour blood coagulation, resulting in production of thromboemboli which can move to distant parts of the circulation, such as the cerebral circulation. Thrombi could also form on surfaces of valves distorted by calcification and other abnormalities. In view of the risks of thromboembolism, it is usual to provide anticoagulant therapy to patients with mitral valve problems and atrial fibrillation. 

ECHO remains the procedure of choice in the diagnosis and evaluation of a number of conditions such as valvular dysfunction (aortic and mitral stenosis and regurgitation and endocarditis), wall motion abnormalities associated with ischemia, and congenital abnormalities, such as ventricular or atrial septal defects. Images obtained from ECHO are used to estimate chamber wall thickness and left ventricle ejection fraction, assess ventricular function, and detect abnormalities of the pericardium such as effusions or thickening. 

Electrocardiogram May be normal or could show numerous abnormalities including acute ST-T-wave changes from myocardial ischemia, atrial fibrillation, bradycardia, and left ventricular hypertrophy. 

Warfarin should be considered in selected patients following an ACS, including patients with a left ventricular thrombus, patients demonstrating extensive ventricular wall motion abnormalities on cardiac echocardiogram, and patients with a history of thromboembolic disease or chronic atrial fibrillation. A more detailed discussion regarding the use of warfarin is available in Chap. 19. 

Patients with diastolic heart failure are typically dependent upon preload to maintain adequate cardiac output. While patients with symptomatic volume overload will benefit from careful modulation of intravascular volume, volume reduction should be accomplished gradually and treatment goals reassessed frequently. In addition to cautious volume management, it is important to maintain synchronous atrial contraction in such patients, which maintains adequate left ventricular filling during the latter phase of diastole. Cardiac function is often severely impaired if patients with diastolic heart failure develop atrial fibrillation, particularly in the context of sub-optimal ventricular rate control. Meticulous control of the ventricular rate with drugs that slow AV conduction is mandatory (see Chapter 34) and restoration of sinus rhythm should be considered. It is also important to evaluate and treat conditions that are associated with dynamic abnormalities of diastolic function, such as myocardial ischemia and poorly controlled systemic hypertension. 

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