Chapter 19 Heart failure and dysrhythmias: Common sequelae of cardiac diseases

Reentry

A complex process in which cardiac impulse continues to depolarize in a part of the heart after the main impulse has finished its path and the majority of the fibers have repolarized

Chronic elevation of myocardial wall tension results in

Hypertrophy

First degree heart block is characterized by

Prolonged PR interval (more than 0.20 sec) on ECG

Second degree block

Is a conduction failure between the sinus impulse and its ventricular response

Sinus bradycardia

Is a slowed impulse generation by the sinus node

Which dysrhythmia is thought to be associated with reentrant mechanisms?

Preexcitation syndrome tachycardia (Wolf-Parkinson-White syndrome)

An abnormally wide ( more than 0.10 second) QRS complex is characteristic of

Premature ventricular complexes ( bizarre in appearance

The foward effects of heart failure cause

inadequate perfusion of the brain and may lead to restlessness, mental fatigue, confusion, anxiety, impaired memory, generalized fatigue, intolerance, and lethargy

Hypertrophy of the right ventricle is a compensatory response to

pulmonary stenosis

Cor pulmonale refers to

right ventricular hypertrophy secondary to pulmonary hypertension

Beta blockers are advocated in the management of of heart failure because they

reduce cardiac output inhibit the cardiac effects of sympathetic activation these drugs are negative inotropes and have the potential to reduce cardiac output

A pt with pure left sided heart failure is likely to exhibit

Pulmonary congestion with dyspnea

The common denominator in all forms of heart failure is

Reduced cardiac output

Lusitropic impairment refers to

Impaired diastolic relaxation

Dysrhythmias are significant since they

Can indicate an underlying disorder Can impair cardiac output

A patient with forward effects of heart failure may present with which symptoms

Impaired memory Mental fatigue Confusion

The therapy that most directly improves cardiac contractility in a pt with systolic heart failure is

Digitalis

paroxysmal nocturnal dyspnea

Dyspnea that occur at night

Increased preload of the cardiac chambers may lead to which patient symptom?

Edema Increased heart rate Increased respirations Fatigue Reduces glomerular filtration resulting in fluid conservation - edema

A patient is diagnosed with heart failure with normal ejection fraction. This patient is most likely characterized by an

Elderly without a previous history MI

Right sided heart failure is usually a consequence of

Elevated right ventricular afterload Right ventricular infarction

Junctional Tachycardia

Has a heart rate between 70 to 140 beats/minute. P waves are preceding, following, or buried in the QRS complex

Left sided heart failure is characterized by

Pulmonary congestion Left-sided heart failure is characterized by pulmonary congestion and edema. Right-sided heart failure is characterized by congestion in the systemic venous system that increases systemic vascular resistance. Jugular vein distention is a classic sign of right-sided heart failure. Peripheral edema is seen in right-sided failure.

A pt has a heart failure with normal ejection fraction. Which findings are most likely found in this patient

Pulmonary congestion Edema Ejection fraction greater than 50%

The majority of tachydysrhythmias are believed to occur because of

Reentry mechanisms

Low cardiac output to the kidneys stimulates the release of ......... from juxtaglomerular cells

Renin

A patient who reports dizziness and who has absent P waves, wide QRS complexes, and a heart rate of 38 beats/ min on an ECG is most likely in which rhythm?

Ventricular escape rhythm - originates in the Purkinje fibers and has a rate of 15 to 40 beats /min, and is characterized by a wide QRS complex An important clue to identify escape rhythms is the absence of normal P waves and PR intervals

In which dysrhythmias should treatment be instituted immediately

Atrial fibrillation with a ventricular rate of 220 Beats/min Atrial fibrillation is a completely disorganized and irregular atrial rhythm accompanied by an irregular ventricular rhythm of variable rate. Atrial fibrillation causes the atria to quiver rather than to contract forcefully. This allows blood to become stagnant in the atria and may lead to formation of thrombi.

Wolff-Parkinson-White Syndrome

Is caused by accessory pathways that originate in the atria, bypass the AV node, enter a site in the ventricular myocardium. This causes the ventricles to contract prematurely, resulting in a reentrant tachycardia

Second degree heart block type 1 (Wenckebach) is characterized by

Lengthening PR intervals and dropped P wave

Acute Cardiogenic Pulmonary Edema

Life threatening condition requiring immediate treatment. It is often associated with left ventricular failure that severely impairs gas exchange, and produces dramatic signs and symptoms including anxiety, severe displeasure, an upright position to breathe effectively and pink frothy sputum

A pt's ECG lacks recognizable waveforms and is deemed to be in sinus arrest. The pt's sinus arrest may be a result of

MI Electrical shock Electrolyte disturbances Acidosis Extreme parasympathetic activity

The most common causes of heart failure are

Myocardial ischemia Hypertension

Triggered activity

Occurs when an impulse is generated during or just after repolarization Due to depolarizing oscillation of the membrane potential

Class IV

Patients have advanced structural heart disease and marked symptoms at rest

Class II

Patients have current or previous symptoms of heart failure

Class III

Patients have current or symptoms of heart failure, such as dyspnea or fatigue

Class I of the NYHA Classes

Patients who have structural heart disease but no s/s of heart failure

Biventricular failure

both ventricles may be dilated and have poor filling and emptying capacity result of primary left ventricular failure that progresses to the right