Hypertension Blog

Diagnostic testing for heart failure includes chest X-ray, ECG, echocardiography, and pulmonary artery catheterization.In a patient with heart failure, a chest X-ray reveals an enlarged heart, indicating hypertrophy or dilation. If the patient is in the early stages of heart failure, the chest X-ray may show congested pulmonary veins in the upper lobes. If he is in the late stages, the X-ray may show interstitial pulmonary edema and pulmonary effusion. If the patient has biventricular failure, the chest X-ray may show a pleural effusion.

A physician uses an ECG to detect left ventricular hypertrophy. An ECG also detects signs of arrhythmias, such as irregular QRS complexes and F waves, and signs of myocardial ischemia, such as T-wave inversion and ST-segment elevation.

Used to measure the size of the heart chambers, echocardiography may reveal an enlarged right or left atrium. This test also is used to assess ventricular function and to detect ventricular hypertrophy. With normal ventricular function, echocardiography shows concentric contractility, a lack of abnormal wall movement, and a left ventricular ejection fraction of 55% to 60%. With left ventricular hypertrophy, it displays a ventricular wall thickness that exceeds 1.2 cm during diastole.

Pulmonary artery catheters are used to measure cardiac pressures. In right ventricular heart failure, the patient’s right atrial pressure may be elevated. In left ventricular heart failure, his pulmonary artery pressure and pulmonary artery wedge pressure are elevated, and CO is reduced.

The diagnostic tests used to detect cerebrovascular disease include computed tomography, Cn scans, magnetic resonance imaging (MRI), cerebral angiography, and digital subtraction angiography.By using a contrast medium to enhance the view of cerebral vessels, a CT scan helps deter­mine whether a patient’s neurologic changes resulted from an ischemic or hemorrhagic CVA. In an ischemic CVA, the CT scan will show areas of decreased absorption or density. In a hemorrhagic CVA, it will show areas of increased absorption or density. If the patient has had an ischemic CVA, a CT scan can help determine the size and location of a thrombus or embolus. A CT scan also can be used to monitor the effects of a patient’s treatment.

If the patient has experienced a hemorrhagic CVA, the physician may order an MRI to precisely locate the lesion.

Cerebral angiography helps identify the location of a hemorrhagic or ischemic CVA. This test also helps determine the extent of damage to the surrounding cerebral tissue, while allowing direct visualization of the cerebral vascular system. However, cerebral angiography may induce a cerebral embolism, cerebral hemorrhage, or spasm.

Digital subtraction angiography commonly is used with cerebral angiography to better visualize the cerebral arteries by computerized fluoroscopy.

Many types of diuretics are used to mobilize edematous fluid, reduce pulmonary vein pressure, and reduce preload. Usually, a physician first prescribes a thiazide diuretic. These drugs reduce hypertension and treat edema by inhibiting sodium reabsorption in the distal renal tubule and promoting sodium and water excretion. If your patient has pulmonary edema, his physician also may prescribe morphine to reduce preload and control anxiety.By acting on the loop of Henle, loop diuretics also promote sodium and water excretion. With thiazide or loop diuretics, the patient may need potassium supplements. Or the physician may prescribe potassium sparing diuretics if the patient is prone to hypokalemia.

The only class of drugs that improves survival in patients with heart failure, vasodilators reduce systemic vascular resistance and pulmonary and peripheral vein pressures, increase left ventricular stroke volume and CO, and enhance myocardial function by reducing myocardial oxygen demand. Sodium nitroprusside, a potent vasodilator, commonly is administered for acute heart failure.

A physician also may prescribe an ACE inhibitor. These drugs prevent the conversion of angiotensin I to angiotensin II, thus increasing CO by reducing systemic vascular resistance.