I degree of AV block
This block cannot be detected clinically, except that splitting of the first sound may sometimes be detected by auscultation (splitting of the atrial component) (Fig. Suppl. 28).
I degree of AV block can only be revealed electrocardiographically:
-increased P-Q interval (> 0.21 s to 0.3-0.4 s and more) without missing QRS;
-regular heart rhythm.
II degree of AV block with Samoilov-Wenckebach periods (Mobitz-1
type)
Conduction of the AV node and His bundle is impaired: each impulse transmitted from the atria to the ventricles increases and the P-Q interval on the ECG becomes longer with each successive beat. A moment arrives at which one impulse does not reach the ventricles and they do not contract, hence the missing QRS complex on an ECG. During a long diastole, which now follows, the conduction power of the atrioventricular system is restored, and next impulses will again be transmitted, but their gradual slowing down will be noted again; the length of the-P-Q interval will again increase in each successive complex. The length of diastole which follows the P wave is called the SamoilovWenckebach period. This type of block is characterized clinically by periodically missing ventricular contractions, and hence missing pulse beats, which correspond to the Samoilov-Wenckebach period.
ECG signs of II degree of AV block with Samoilov-Wenckebach periods (Mobitz-1 type) (Fig. Suppl. 29):
-gradual elongation PQ (Samoilov-Wenckebach periods);
-periodically missing ventricular contractions.
II degree of AV block (Mobitz-2 type)
The second-degree atrioventricular block can be characterized by a worse conduction. The P-Q interval remains constant, but only each second, third, or (less frequently) fourth impulse is transmitted to the ventricles. The number of P waves on the ECG is therefore larger than of ventricular complexes. This is known as incomplete heart block with a 2:1, 3:1, etc. ratio. Considerable deceleration of the ventricular rhythm and slow pulse are characteristic, especially in 2:1 block. If each third or fourth beat is missing, the pulse is irregular and resembles trigeminy or quadrigeminy with early extrasystoles and pulse deficit. If the heart rhythm slows down significantly, the patient may complain of giddiness, everything going black before his eyes, and transient loss of consciousness due to hypoxia of the brain.
ECG signs of II degree of AV block (Mobitz-2 type) (Fig. Suppl. 30):
-periodic missing QRS without gradual elongation PQ (2:1, 3:1);
-PQ can be normal or a little bit prolonged.
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III degree of AV block (complete heart block)
There is no electrical communication between the atria and the ventricles, and sinus node becomes the only pacemaker for the atria. The ventricles contract by their own automaticity in the centres of the second or third order (about 30-40 per min).
ECG signs of complete heart block:
1)atrial P waves and ventricular complexes QRS are recorded independently of each other;
2)the number of QRS is usually much smaller than the number of atrial P waves;
3)the shape of the ventricular complex does not change if the pacemaker arises from the AV node or His bundle;
4)with lower location of the pacemaker in the conduction system, the QRST complexes are altered.
The heart rate in persistent complete heart block may be sufficiently high (4050 beats/min) but the patient may be unaware of the disease for a long time. Examination of such patients reveals slow, rhythmic, and full pulse. The heart sounds are dulled but a loud first sound ("pistol-shot" sound according to Strazhesko) may be heard periodically. It occurs due to coincidence of the atrial and ventricular contractions. If the ventricular rhythm slows down significantly (to 20 beats/min and less), or the heart misses a beat when incomplete heart block converts into a complete one, i.e. when the impulses from the atria are not conducted to the ventricles, while their automaticity has not yet developed, attacks (the Morgagni-Adams- Stokes syndrome) may occur due to disordered blood supply, mainly to the central nervous system. During an attack the patient loses consciousness, falls, general epileptiform convulsions develop, the respiration becomes deep, the skin pallid, the pulse very slow or even impalpable. When the ventricular automaticity restores, the patient regains his consciousness and all other signs of the syndrome disappear. If automaticity is not restored for a time, fatal outcome is possible.
His bundle branch blocks
Intraventricular block usually develops as the right or left bundlebranch block. The left limb of the His bundle ramifies almost immediately to give left anterior and left posterior branches. Only one branch can therefore be blocked. Block of the right limb may be combined with block of the branches of the left limb. In complete block of either of the limbs, the impulse from the sino-atrial node is normally conducted through the AV node and the main part of the His bundle to meet an obstacle to its conduction in that ventricle whose branch is affected. The ventricle with the intact branch is therefore first excited and excitation is transmitted to the
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ventricle with the affected branch. The ventricles are thus excited slowly and in an unusual way.
ECG signs of His bundle branch blocks:
(1)P wave does not change;
(2)ventricles contract rhythmically by the impulse from the sinus
node;
(3)QRS complexes are markedly altered and widened ≥ 0.12-0.18 s and resemble complexes in ventricular extrasystole;
(4)The shape of the ventricular complexes depends on the particular bundle branch which is blocked.
ECG in left bundle branch block is characterized (Fig. Suppl. 32):
-wide and deformed QRS has the form of qR in I, II, V5-6; rS in III, aVF, V1-2 (the shape of the ventricular complexes resembles that of right ventricular extrasystoles);
-disconcordance of ST, T and the main wave of QRS; - levogram.
ECG in right bundle branch block is characterized (Fig. Suppl. 33):
-wide QRS in III, V1-2 has the form of rsR, rSR, RsR´(similar to “M”) (the shape of the ventricular complexes resembles that of leftventricular extrasystoles);
-wide S in I, aVL,V5-6;
-negative ST and T in V1-2;
-dextrogram.
Examination of patients with diseases of esophagus, stomach and intestines:
Subjective examination of patients. Objective examination of patients: survey, percussion and auscultation of abdomen
Subjective investigation in diseases of digestive system
Complaints of patients with diseases of a digestive system depend on the organ having the pathological changes. Pains and dyspeptic symptoms are the most often complaints at diseases of the digestive system. It is necessary to distinguish, however, pains from a heavy feeling, strains, distension or pressure in an abdomen, which patients quite often combine in one concept of "pain".
Detailed elaboration of a pain syndrome includes: localization of a pain with statement of the following questions: character of sensation; periodicity or a persistence of it; connection with reception of nutrition (or defecation, physical and emotional activity) and its quality; presence or absence of
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irradiation; a position of the patient at the moment of an attack; how pains are revealed (a vomiting, medicines, a heater).
Dyspepsia means literally «disorders of digestion». Dyspeptic symptoms connect with affections of digestion and/or passage of nutrition in definite parts of alimentary tract.
Subjective investigation in diseases of esophagus
Complaints
Dysphagia (difficult passage of food via the esophagus) is the most frequent symptom of esophageal pathology. The patient feels difficulty in swallowing (mostly solid food); the food bolus sometimes stops in the esophagus and the patient feels pain and esophageal distention, sensation of a lump in a throat or thorax, sense of pressure in range of an esophagus or difficulty of transit of nutrition.
Dysphagia can be due to organic or functional narrowing of the esophagus. Organic stenosis develops gradually and progresses in cancer, and cicatricial stenosis of the esophagus. Solid food first passes with difficulty, then the patient feels difficulty in swallowing soft, and then liquid food. When cancer tumour disintegrates, patency of the esophagus may be restored almost completely. Dysphagia develops immediately in the presence of a foreign body or if the esophagus is burnt. Dysphagia may also develop due to compression from outside by an aortic aneurysm or mediastinal tumour.
Functional narrowing of the esophagus is explained by muscular spasms caused by reflex disorders of innervation of the esophageal muscles, or by neurosis. As distinct from organic dysphagia, functional dysphagia more often occurs in paroxysms when food passes the esophagus. Sometimes solid food passes more readily than liquid.
Pain occurs in acute inflammation of the esophageal mucosa (esophagitis) and in burns. The patient usually feels pain by the course of the entire esophagus, both with and without swallowing; pain may radiate into the interscapular region.
Patients with achalasia of the cardia (cardiospasm) may have spontaneous attacks of pain, usually during night. Pain is quite severe; it radiates into the back, upwards by the esophagus, into the neck, the jaws, and continues for minutes and even hours. In the presence of hiatus hernia and gastroesophageal reflux, pain may radiate into the left side of the chest and simulate heart diseases.
Esophageal vomiting occurs in considerable narrowing of the esophagus. Food is accumulated over the constricted point, in the wider portion of the esophagus, and is expelled by antiperistaltic contractions of the muscles, Esophageal vomiting differs from gastric vomiting in the following: it occurs without nausea and is preceded by the feeling of food retained behind the sternum; the vomitus includes unaltered (non-digested) food
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which contains neither hydrochloric acid (gastric juice) nor pepsin; the vomitus containing food that has been taken long time ago has foul odour; taken food can be retained for long periods in the presence of esophageal diverticulum or degrading cancer.
Regurgitation is the return of swallowed food into the mouth due to esophageal obstruction. Regurgitation sometimes occurs in neuropathic patients in whom it becomes a habitual symptom or a result of cardiospasm.
Hypersalivation occurs in esophagitis, cicatricial narrowing of the esophagus or in cancerous stenosis as a result of the esophago-salivary reflex.
A foul breath may be due to a cancer tumour of the esophagus or congestion and decomposition of food in cardiospasm.
Heartburn (pyrosis) is a specific burning sensation behind the sternum associated with regurgitation of gastric contents into the inferior portion of the esophagus. This is the cause of the so-called reflux esophagitis.
Hemorrhage can be due to ulcer of the esophagus, injury to the esophagus by a foreign body, degradation of a tumour, bleeding of dilated esophageal veins (which occurs in congestion of blood in the portal vein system), and also bleeding of the mucosa due to small lacerations of the vessels in the esophagogastric junction in straining and vomiting (MalloryWeiss syndrome).
History of present disease
In organic affections of the esophagus, the disease has a progressive course. Functional diseases (cardiospasm) are characterized by exacerbations connected with psychogenic factors which are followed by remissions. From the anamnesis of the patient's life it can be established whether the patient had past burns of the esophagus, since acid or alkali burns are frequent causes of cicatricial changes in the esophagus. Syphilis is an important disease of the past history since the patient's complaints of dysphagia can sometimes be associated with syphilitic aortitis (compression of the esophagus by a dilated aorta). Development of traction diverticula in the esophagus may be due to bronchoadenitis in the past (tuberculous bronchoadenitis included). Pulsion diverticula arise due to esophagospasm.
Subjective investigation in diseases of stomach and duodenum
Complaints
Patients with diseases of the stomach complain of poor appetite, perverted taste, regurgitation, heartburn, nausea, vomiting, epigastric pain, and hematemesis. Regurgitation, heartburn, nausea, vomiting, and the feeling of overfilled stomach after meals are the group of the so-called dyspeptic complaints. These symptoms may be observed in diseases of some other organs and systems. Determining the specific character of each symptom is important during inquiry of the patient.
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