Complete Heart Block: Causes, Symptoms, ECG Findings, and Treatment

Complete Heart Block: Causes, Symptoms, ECG Findings, and Treatment

Question. Describe briefl complete heart block.

Answer. Complete heart block is also known as third degree heart block or complete AV block

Etiology
1. Congenital:

1. Usually associated with ventricular septal defect,rarely isolated.

2. Acquired:

Rheumatic heart disease

Complete Heart Block: Causes, Symptoms, ECG Findings, and Treatment

1. Acute infections—rheumatic fever, diphtheria
2. Drugs—Digitalis, quinidine
3. Calcifi aortic stenosis.
4. Trauma (penetrating).
5. Surgical procedures: After correction of ventricular septal defect, or following insertion of prosthetic valves or removal of hypertrophied septum in
   hypertrophic cardiomyopathy.
6. Cardiomyopathy (particularly infitrative).
7. Syphilitic heart disease.
8. Infitrative masses: Sarcoidosis, tubercles, abscesses from endocarditis, gummas, tumors, amyloidosis, hemochromatosis.
9. Collagendiseases: Rheumatoid arthritis, dermatomyositis.
10. Fistulae: Sinus of Valsalva aneurysm rupturing into right atrium.
11. Unknown cause: Idiopathic firosis.

Complete Heart Block: Causes, Symptoms, ECG Findings, and Treatment

Clinical Features Marfan’s syndrome.

Symptoms Marfan’s syndrome.

1. Due to low cardiac output: Lassitude, fatigue, light headedness, and especially during exercise syncope.
2. Symptoms of vertebrobasilar insuffiency and congestive heart failure may be precipitated.
3. Due to increased stroke volume: Uncomfortable awareness of heart beat, or slow palpitation, if block is intermitnt.
4. Due to transient circulatory arrest: Stokes-Adams atcks Symptoms depend on duration of standstill of circulation: About 5 seconds—giddiness and faintness, about 10 seconds—convulsions.
5. Convulsions and incontinence may suggest epilepsy, but in transient asystole pallor is often striking, patient flshes during recovery, and consciousness is regained very rapidly; though some permanent impairment of cerebral function may occur after long or repeated episodes.

Causes and Risk Factors of Complete Heart Block

Signs Marfan’s syndrome.

1. Slow and regular heart rate: At 30 to 50 beats per minute,which does not usually increase signifiant with physical activity or exercise.
2. Raised Jugular venous pressure: ‘a’ waves may be seen in the neck unrelated to ventricular beats.
3. Cannon waves: Giant ‘a’ waves which are transmittd in the neck when the atrium contracts against a closed tricuspid valve.
4. Variation in intensity ofFirst heart sound: First heart sound is loudest when the interval between the preceding atrial beat and the ventricular beat is short, it is faintest when the interval is long.
   From time to time, there is a sharp accentuation of the fist sound at the apex (cannon sound).
5. Tide pulse pressure: Due to increased systolic pressure and low diastolic pressure. This gives rise to water hammer pulse and capillary pulsation.
6. Cardiac enlargement: Due to increased stroke volume, hyperdynamic cardiac impulse.
7. Systolic ejection murmur: Loudest in 2nd and 3rd left interspaces adjacent to the sternal edge, and due to increased velocity of blood flw associated with increased stroke volume.
8. Atrial sounds: They may be heard in constant relation to fist and second heart sounds.
9. Apical diastolic flw murmur: It is occasional.
10. ECG: There is no relation between atrial and ventricular complexes. The duration of QRS is normal..

Symptoms of Complete Heart Block and Diagnosis

Management Marfan’s Syndrome.

In Acute Complete av Block

Acute onset of complete AV block occurs in acute myocardial infarction, i.e. in inferior myocardial infarction and anterior myocardial infarction.

Complete AV Block with Inferior Myocardial Infarction

1. Complete AV block occurs usually in acute inferior wall infarction but are transient and less troublesome.
   No treatment is needed in such patients who are well and hemodynamically stable. If in such cases, clinical deterioration occurs, then atropine 0.6 mg IV can be given as a bolus and repeated, if necessary.
   If this treatment fails, then a temporary pacemaker may be inserted.
   In most of the patients, heart block disappears under 7–10 days.

Complete AV Block with Anterior Myocardial Infarction

1. This occurs less commonly, is dangerous and carry poor prognosis.
   Asystole commonly occurs in such cases and lead to mortality.
   If patients develop asystole, atropine 0.6 mg IV given as bolus and repeated, if needed. Temporary pacemaker is inserted immediately. Isoprenaline infusion, i.e.
   1 to 5 mg in 500 mL of 5% dextrose should be started at minimum rate to produce a satisfactory heart rhythm till temporary pacemaker is inserted.
2. If blockisduetodrugtoxicity, strictlystoptheoffndingdrug.

Symptoms of Complete Heart Block and Diagnosis

Chronic complete av block

A permanent pacemaker is indicated in patients having asymptomatic Mobit type II complete heart block because it can improve their prognosis.