Left atrial hypertrophy

Etiologies of AF are presented in Table 6—4. The common feature of the majority of etiologies of AF is the development of left atrial hypertrophy. Hypertension maybe the most important... 

LAG LAH LAL LAM LAN LAO LAP lymphangiogram left atrial hypertrophy left axillary line limulus amebocyte lysate Latin American male lymphadenopathy left anterior oblique laparotomy laparoscopy left arterial pressure leukocyte leucine amino peptidase... 

Supraventricular tachycardia/ atrial fibrillation Left ventricular hypertrophy Myocardial ischemia... 

Thorough cardiac examination should look for possible cardiac source of embolism, including atrial fibrillation, mitral stenosis and prosthetic heart valves. Left ventricular hypertrophy suggests hypertension or aortic stenosis, and a displaced apex from a dilated left ventricle indicates underlying cardiac or valvular pathology. 

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. 

The most important modifiable risk factor for stroke is hypertension. The treatment of hypertension, beginning in the midtwentieth century, is thought to be primarily responsible for the drastic reduction in stroke death rates between 1950 and 1980 in the United States. A second very important risk factor for stroke is cardiac disease. Patients with coronary artery disease, congestive heart failure, left ventricular hypertrophy, and especially atrial fibrillation are at increased risk of stroke. In fact, the presence of atrial fibrillation is one of the most potent risk factors for ischemic stroke, with stroke... 

Numerous neuroendocrine biomarkers correlate with severity of cardiac dysfunction. Heart failure is associated with increase in peripheral vascular resistance due to increases in sympathetic tone, norepinephrine, renin, angiotensin II, arginine vasopressin, and endothelin-1. The increased venous pressure causes atrial distension that stimulates production and release of atrial and brain natriuretic peptides (ANP, BNP) from the atria and ventricles, respectively. ANP inhibits the renin-angiotensin-aldosterone system. In humans and mammals, BNP has been found to be an early biomarker of left ventricular hypertrophy developing with doxorubicin cardiotoxicity, congestive heart failure, or occult dilated cardiomyopathy (Erkus et al. 2006 Walker 2006 Oyama, Sisson, and Solter 2007). 

Schirmer, H., Omland, T. (1999). Circulating N-terminal pro-atrial natriuretic peptide is an independent predictor of left ventricular hypertrophy in the general population. Eur. Heart J. 20 755-763. 

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). 

Approximately 25% of all patients with hypertrophic cardiomyopathy (HCM) have latent left ventricular outflow obstruction with an intraventricular gradient (I). Pathophysiologic features are asymmetric hypertrophy of the septum and a systolic anterior movement of the anterior leaflet. Medical treatment includes betablockers, and calcium antagonists of the verapamil type. Approximately 5— 10% of the patients with outflow obstruction are refractory to such negative inotropic therapy (2). Positive inotropic drugs such as digitalis or sympathomimetics are strictly contraindicated. In the presence of atrial fibrillation, anticoagulation therapy should be started. Since endocarditis is more common in patients with HCM because of turbulence in the left ventricle, prophylactic antibiotics should be administered for periods of potential bacteraemia. 

Left and right atrial enlargement is often found in the presence of an associated ventricular enlargement or hypertrophy. 

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