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More common in neonates and Congenital diaphragmatic hernia is no longer infants discount abilify 10mg otc depression facebook, the clinical picture includes recurrent forceful considered a surgical emergency; instead it is a bilious vomitings without abdominal distension discount abilify 15mg line depression rehab centers. Once stable the child is taken up for laparotomy and reduction of viscera with large stomach bubble with few distal gas shadows order abilify 20mg on line mood disorder assessment. Good results can be expected if meal studies show that the duodenojejunal junction lies the pulmonary hypoplasia is not very severe. Te small bowel loops are predominantly on the left side of the Duodenal and Other Intestinal Atresias abdominal cavity. Partial or complete occlusion of the intestinal lumen may Ultrasound may show abnormal orientation of the occur congenitally in any part of the intestine commonly superior mesenteric artery and veins establishing the diagnosis. Treatment is exploratory laparotomy followed Ultrasound will show a target sign in upper abdomen 821 by lysis of the Ladd’s bands and widening of the base of or in left iliac fossa due to presence of intussusceptum the mesentery. Barium enema may show the intussusception as an inverted cap or a claw sign may be seen. Tere Intussusception is an obstruction to the retrograde progression of Te disorder is characterized by telescoping of one of the barium into ascending colon and cecum. In the area portions of the intestine into a more distal portion, leading of intussusception, there may be a ceiling-spring to impairment of the blood supply and necrosis of the appearance to the column of barium. Of the three forms (ileocolic, ileoileal Treatment and colocolic), ileocolic is the most common. It is the most Conservative hydrostatic reduction gives good results frequent cause of intestinal obstruction during the frst 2 years of life. It is performed by insertion of an unlubricated Te most common form is idiopathic and occurs classically balloon catheter into the rectum. Te predisposing factors include of 90 cm, barium is allowed to fow into the rectum. Under Henoch-Schönlein purpura, Meckel’s diverticulum, fuoroscopy, the progress of barium is noticed. Total parasites, constipation, inspissated fecal matter in cystic reduction is judged from: fbrosis, foreign body, lymphoma and infection with Free fow of barium into the cecum and refux into the rotavirus or adenovirus. Fever and prostration are Passage of charcoal, placed in child’s stomach by the usually appear 24 hours after the onset of intussusception nasogastric tube, per rectum. Surgical reduction is indicated in patients who are A sausage-shaped lump may be palpable in the upper unft for hydrostatic reduction or who fail to respond to abdomen in early stages. Spontaneous reduction with recurrent episodes is known Plain X-ray abdomen may reveal absence of bowel in older children. Hirschsprung’s Disease (Congenital Megacolon) Tis disorder results from absence of parasympathetic ganglion cells in both Meissner and Auerbach’s plexuses at rectosigmoid segment with or without involvement of some additional part of the distal large bowel. Clinical Features Constipation (persistent, not responding to various measures), abdominal distention, vomiting and growth failure may begin soon after birth. Te patient is generally grossly malnourished with multiple nutritional defciencies. Te viscid X-rays: An upright plain flm shows remarkably mucus tends to choke the lumen of the intestine, causing distended bowel with gas and stools. At times, air-f1uid manifestations of distal intestinal obstruction notably levels and air in the wall of the gut may be present. At times, Barium enema: In a newborn, barium enema may meconium may be palpable in the right lower quadrant of show prolonged retention of barium for over 24 hours. In later age group, it shows that the involved segment A plain abdominal X-ray reveals dilated intestine is constricted and has irregular outline. Te colon without fuid levels and a gastrografn enema highlights proximal to this spastic segment is grossly distended. Treatment is surgery, provided that the In between the distended and the constricted segment enema has failed to relieve the obstruction by dissolving there is so called transition zone which is considered the inspissated mucus. In a less classical enterostomy to facilitate the wash outs directly from the case, the only fnding may be rectosigmoid inversion, terminal ileum or creation of a double barrel or a Y stoma. Meckel’s Diverticulum Rectal biopsy: Tis is the gold standard for making Abnormal persistence of embryologic vitellointestinal the diagnosis. It is seen in 2% of in such a child is about 5 cm above mucocutaneous population, 2 feet (60 cm) from the ileocecal junction, junction. Absence of ganglion cells in the plexuses is generally 2 inch (5 cm) long, containing heterotopic confrms the diagnosis. During this period attempts should due to a band going up to umbilicus or perforation be made to maintain fuid and electrolyte balance and to secondary to ulceration due to ectopic gastric mucosa. Antibiotics are indicated in Some cases may present with right lower quadrant pain the presence of enterocolitis, which is quite common and presumably due to infammation of the diverticulum. Te treatment of choice is surgery, involving resection Diagnosis of the involved (aganglionic) segment and end-to-end Most important diagnostic tool is high index of suspicion. Te best time to perform the main operation is at or Necrotizing Enterocolitis soon after the infant has attained the age of 6 months. It is discussed in details in Chapter 17 obstruction or perforation, which may prove fatal. Defnite indications Probable indications z A palpable abdominal lump z Abdominal tenderness Meconium Plug Syndrome z Pneumoperitoneum z Severe hemorrhage Te term refers to impaction of a thick plug of meconium z Abdominal wall erythema z Clinical deterioration in the distal colon leading to manifestations of intestinal z Positive abdominal tap z Platelets <100,000/mm3 obstruction. It usually responds to a rectal wash, which (paracentesis) brings out the obstructing meconium plug. It has a broad whitish head and a greenish meconium tail followed by z X-ray abdomen a light-colored meconium. Some neonates may need z (Dilated loops, gasless with ascites) another wash before proper defecation pattern develops. Later, pain shifts bleeding and usually follows a tear or small laceration of to right lower quadrant due to irritation of the adjacent the mucocutaneous junction of the anus during passage peritoneum. Untreated cases go on to develop perforation of a hard fecal matter in a severely constipated child. Te pain becomes generalized, fever and vicious cycle of constipation—painful defecation—stool tachycardia increase and the abdomen becomes tender retention—constipation sets in. Treatment aims at softening seals of and localizes the peritonitis, and an abscess is stools by dietary correction and use of stool softeners so formed in the right lower quadrant or pelvis. Surgical intervention A persistent direct tenderness over McBurney’s in the form of excision of the fssure, anal sphincterotomy point and rigidity of the overlying rectus muscle is highly or stretching of anus is in actuality not required. A self-limiting benign form, which occurs in infants Te appropriate treatment for acute appendicitis is with no particular predisposition and requires no surgical appendectomy within a few hours of diagnosis. A serious form which occurs after the age of 2 years be drained by open or percutaneous technique and and has predisposing factors such as neutropenia, leu- appendectomy performed in 4–6 weeks. Malformations Manifestations in the benign type include fever, rectal Imperforate anus with fstula may be of high, intermediate pain and perianal cellulitis. Occasionally, it may above the levator ani funnel and the fstula opens into need drainage under local anesthesia. If a fstula has been the urinary bladder (rectovesical fstula) at the level of the formed, a fstulectomy is required.
Te infant doubles his birth weight by the age of 4–6 Somatic Growth months and trebles it by one year purchase abilify online depression symptoms loss of appetite. He increases it four times It has two components—(1) skeletal maturity and (2) erup- by two years order abilify with paypal depression group activities, fve times by three years order abilify 10 mg fast delivery depression symptoms anhedonia, six times by fve years tion of teeth. It rises to 60 cm at three months, 70 cm at nine Weight (kg) at 7–12 years = 2 months, 75 cm at one year, 90 cm at two years, 95 cm at three years and 100 cm at four years. For feld, an Indian modifcation of the famous English For convenience, you may remember: Length (cm) at birth = 50 Salter spring machine (Fig. It is a portable Height (cm) at 2–12 years = age (years) × 6 + 77 gadget, weighing only two kg, and is accurate upto 100 g. A Half of the adult height is attained by two years in girls and 2½ years scale that can record upto 20 kg is available. Toddlers and older children and adoles- better option for weighing toddlers, older children and adolescents. In case this kind of an infantometer is not readily available, the purpose is served with a fabricated infantometer employing a book at the head-end and another at the foot-end of the infant (in lying down posture). Proper alignment of head and feet and straightening of legs is important for accuracy. For children under two years, it is advisable to measure the recumbent length, while the child lies supine, (with legs fully extended at hips and knees and feet at right angles to legs) in the so-called infantometer (Fig. Such an infantometer may be fabricated by placing a book vertically at the head-end and another at the foot-end. Arms should hang naturally by period, rather than weight, it is the height that is more the sides. Te line joining the upper margin of the external useful as an indicator of growth, especially when two auditory meatus and lower margin of the orbits (Frankfort measurements are recorded at an interval of about six horizontal plane) should be in the plane parallel to the months. Te height should be recorded height needs to be measured on more than one occasion to the nearest 0. Now, digital ultrasonic over a period of time and the increment in height divided height measuring system too has become available. With the greater Birth 35 increase in the length of the legs compared to the 3 months 41 trunk, the ratio is 1. Tereafter, lower segment tends to 3 years 50 show a slight edge over the upper segment, the ratio being 0. Span is the distance between tips of middle fngers when the arms are outstretched. Te tape (non-stretchable) is placed over the occiput at the back and just above the supraorbital ridges in front (mid forehead). Measurement of chest circumference 41 cm (against a normal of 47 cm), global developmental delay and at the level of the nipples. Head/Chest Circumference Ratio At birth, head circumference is larger than chest circumfer- ence by about 2. By the age of fve years, it is more or less 5 cm greater in size than the head circumference. Ten place the tape frmly, but without compressing the tissues around the upper arm at a point midway between tip of Fig. Skin-fold Thickness z Late closure should arouse suspicion of rickets, congenital hypothyroidism, hydrocephalus, syphi- Of the various skin-folds (subscapular, biceps and triceps), lis, protein-energy malnutrition, etc. A fold of skin is held between the thumb and , ^d /Z hD& Z E index fnger and measured. For measuring chest circumference place the tape at the Ratio of total body water and body weight is a more level of the nipples (or xiphisternum) in a plane at right accurate index of body fat, correlating at about 0. An average full-term newborn has fve radiologically demonstrable ossifcation centers (Box 3. Ossifcation of the carpal bones occurs in a predictable sequence, starting with the capitate and ending with the pisiform (Figs 3. It is a useful guide to remember that number of centers at wrist is equal to age in years plus one. Tus, a child of two years should Body Mass Index have three centers in an X-ray of wrist. If possible the child should stand erect and sideways to the Generally, the lower central and lateral incisors erupt measurer. Delayed eruption of frst tooth (upto as late as 15 months) z When the tape is in the correct position and correct tension on the in a normal child is also seen. Likewise, late appearance of arm, read and call out the measurement to the nearest 0. Among the possible factors responsible for delayed dentition include: Familial and/or racial tendency, Dentition Poor nutritional status, It is not a dependable parameter for assessment of growth Rickets, since there is a wide variation in the eruption of teeth and Osteogenesis imperfecta. Very infrequently, a child may have an absolute non- Te average age at which frst tooth erupts is eruption of teeth (anodontid) which is a classical feature 6–7 months. This is the most dependable and accurate caliper for measuring skin-fold thickness. Each division on the be responsible for excessive salivation and drooling, irrita- scale is 0. Local application of choline salicylate and an oral analgesic or a mild seda- Discoloration of temporary teeth right from the start tive should sufce. Between 1 and 12 years of age, z Pseudohypoparathyroidism radiograph of hand and wrist is most often employed for determination z Acrodysotosis of bone age. Lymphoid tissue shows enormous growth, going much beyond the adult size during early adolescence. David Morley, growth chart is def- should also be taken into consideration For instance: ned as a visible display of child’s growth and development. Birth Nil 6–7 months Central incisors Applications (Uses) By 10 months Laterals incisors Te chart is meant: 1–1½ years First molars To make growth a tangible visible attribute. It should, therefore, be sufciently attractive and designed to facilitate accurate recording in a simple Table 3. A fat curve indicates a slowed or arrested growth which must Features alert the attending doctor to take action, both diagnostic as to its cause and corrective so as to lead to normal growth Te strategy recognizes growth to be the result of once again. Growth monitoring is best initiated from birth rather Government of India growth chart, as modifed in than when the child is already 2–3 years old. Perhaps, the defciency lies in chart has over and above the standard, 3 reference modus operandi in execution rather than an inherent lines. Nevertheless, Specifc components catch-up growth is likely to be signifcantly less in case Age group of monitoring Schedule of recurrent episodes of growth inhibitory factors. Obviously, the hormonal factors (especially the Monitoring linear catch-up growth is of great clinical somatotrophic axis) and the epiphyseal growth plate are importance because of its value in measuring the efcacy of paramount importance in catch-up growth. Te three available hypotheses are given It is defned as height velocity above statistical limits of in Box 3. It is intended to revert the child to his pre-retardation Te question whether the developing countries should growth curve. It is the rapid growth targeted at making use international growth standards or develop their own up for the loss of potential tissue. Te latter is Te argument that all children have same genetic poten- the growth that occurs after a loss of the actual mass of tial/especially in early years, and their growth is more tissue that is controlled by a simple feedback mecha- infuenced by nutrition, illness, and environment rather nism working on physiological mass.
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The reasons for these women failing to seek help have not been properly determined buy abilify 10 mg without prescription depression symptoms tumblr. It may be that women lack the financial resources for a problem that only has an impact on her quality of life 15mg abilify with mastercard depression symptoms not sad. Another possibility is the perception that nothing can be done about the problem and this may be reinforced by the relative lack of training in managing female pelvic floor dysfunction in large parts of Africa quality abilify 15 mg anxiety 7dfps. Women on the continent also play an important socioeconomic role in their respective communities and may not prioritize seeking help for quality of life issues such as incontinence or pelvic organ prolapse. It is also important to note that in many parts of Africa, women are not empowered regarding their health and their reproductive health in particular. Fistula-Related Incontinence Obstetric fistulas are overwhelmingly the most important problem in female pelvic floor dysfunction in Africa. They are a devastating condition that leave women profoundly stigmatized and isolated from their communities. When one considers the pathophysiological mechanism responsible for the development of an obstetric fistula, the patient experience in the evolution of a fistula is horrifying. Prolonged, neglected obstructed labor will result in the fetal head being wedged into the maternal pelvis, leading to increasing tissue necrosis. Fetal death then occurs and macerates results in softening and eventual passage of the soft, macerated body [9]. If the woman survives this ordeal, the ensuing maternal injuries are often extensive. Many urogynecologists working in well-developed settings will be astounded by the extent of bladder and urethral injuries incurred by many of these women. This often includes either partial or total necrosis of the urethra, total avulsion of the urethra from the bladder, and extensive defects of the bladder itself. In addition to vesicovaginal fistula, many women have severe vaginal scarring and the cervix is often destroyed. A study in Nigeria found that 32% of women with fistula also had significant skeletal injuries, including symphyseal separation with gait abnormalities, marginal fractures, bone spurs, and complete obliteration of the symphysis [10]. The United Nations Population Fund in 2003 launched a global campaign to end fistula [11]. This was calculated from data extrapolated from two studies that included 28,128 participants. One of the largest studies was a prospective population study of 19,342 women in west Africa [13], and this reported a prevalence for fistulas of 10. Extrapolating from these data, the authors estimate a prevalence of 33,451 new obstetric fistulas per year for sub-Saharan Africa. Another cross-sectional study [14], this time reporting on data captured in Ethiopia, found a prevalence of 2. The 2005 Malawi Demographic and Health Survey [15] collected national prevalence data on fistula through a proxy measure of symptoms. After interviewing 11,698 women, a crude rate of 1,557 per 100,000 live births and a lifetime prevalence of 4. Sobering demographic data on fistula emerged from a sample of women treated at the renowned Addis Ababa Fistula Hospital between 1983 and 1988 [16]. The mean age was 22 years, 42% were younger than 20 years of age, 52% had been deserted by their husbands, and 21% lived by begging. Furthermore, 30% had delivered without assistance and the average labor had lasted 3. Kelly and Kwast [17] also reported on a sample of 309 women attending in the Hamlin Bahir Dar Fistula Centre in Ethiopia and found that 82% had travelled at least 700 km for treatment, walking an average of 12 hours, and spending an average of 34 hours on a bus, before arriving at the treatment center. Wall and colleagues [18] analyzed 899 obstetric fistula patients from Jos, Nigeria, and found that women with fistulas tended to have been married early (often before menarche), to be short (nearly 80% were less than 150cm tall) and small (mean weight less than 44 kg), to be impoverished and poorly educated, and to live in rural areas. Kelly [16] report that more than 50% of women with fistulas had been rejected by their husbands. Urinary incontinence may occur if there is direct injury to the bladder or urethra. It may also obstruct the vaginal outlet and hence make fistulas more common following delivery. Peterman and Johnson [20] could not find a significant relationship in their Demographic and Health Surveys study in Malawi, Rwanda, Uganda, and Ethiopia. Eighty-eight percent of women had undergone excision and infundibulation is 88%, 6. Thirteen percent of the women experienced late complications including pain at micturition, dribble incontinence, and poor urine flow. Various traditional African remedies are also associated with the development of fistulas. The Northern Nigerian practice of “gishri cutting” involves making a series of vaginal incisions with a glass, a blade, or a knife. Between 2% and 13% of women undergoing this gishri procedure will get a fistula [18]. Herbal remedies for various gynecological conditions, which involve the insertion of caustic chemicals vaginally, are also often used by traditional Africa healers [22]. The ensuing vaginal fibrosis and stenosis will occasionally lead to fistula formation. Fistulas caused by sexual abuse and rape are a particularly troubling phenomenon [23]. Peterman and Johnson [20] used the recent Demographic and Health Surveys in Malawi, Rwanda, Uganda, and Ethiopia to determine the relationship between sexual violence, female genital cutting, and incontinence. Sexual violence was a significant determinant of incontinence in Rwanda and Malawi but not in Uganda. They suggest that elimination of sexual violence will result in up to a 40% reduction of the burden of incontinence. In situations of conflict, refugees and displaced women and girls often have been sexually assaulted. In wartime conditions, sexual violence is a commonly used tactic to intimidate and control. Aid workers have estimated that in war-affected areas, one woman in three is a rape victim, and the majority of new nonobstetric fistula cases are caused by sexual violence. Fistula reconstructive surgery is complex and usually requires a high level of experience and skill. Most gynecologists, urologists, and general surgeons will not be able to offer this service without extensive training, and therefore, access to surgery varies extensively in sub-Saharan countries. Most women are dependent on the goodwill of itinerant surgeons who offer their services at little or no cost. In 2004, Browning [24] calculated that it will take 400 years to catch up on the backlog of candidates waiting for surgery and a concerted effort to train local physicians in the management of fistula is therefore required. The support of the international community is also mandatory, and this includes increasing involvement from the large organizations involved in continence care, including the International Urogynecological Association and the International Continence Society. It is important to note that a significant proportion of women remain incontinent following repair of vesicovaginal fistula [24–26]. They concluded that the reduced success rates following surgery for fistula may be due to the lack of attention to the other reasons for urinary symptoms and markedly impaired urethral function.
We also assessed the difference in dispersion of refractoriness when refractory periods are determined at both twice threshold and at 10 mA (in our experience this is always on the steep portion of the strength–interval curve) order abilify 15 mg otc depression symptoms self help. Thus purchase discount abilify on-line economic depression definition pdf, we evaluated both dispersion of refractoriness and dispersion of recovery (local activation plus local refractoriness) at each site buy abilify 10 mg visa anxiety jackets for dogs. In five patients, we studied the effect of drive cycle length on dispersion of refractoriness. At a paced cycle length of 600 msec, the dispersion of refractoriness was 66 ± 41 msec, and it was similar at a paced cycle length of 400 msec at 65 ± 45 msec. Total dispersion of recovery was 89 ± 40 msec at a paced cycle length of 600 and 88 ± 38 msec at a paced cycle length of 400 msec. Of note, the maximum dispersion at any two adjacent sites of refractoriness was 33 ± 12 msec, and for total recovery it was 41 ± 15 msec. Thus, in our studies,43 cycle lengths from 600 to 400 msec did not alter dispersion of refractoriness, as seen in experimental studies. In these patients we found no significant difference in dispersion of refractoriness. The dispersion of refractoriness was 62 msec at twice threshold and 50 msec at 10 mA, and the total recovery was 79 msec at twice threshold and 68 msec at 10 mA. A limitation of these preliminary data is that in these patients, dispersion measurement methods were mixed, some having twice threshold and 10 mA performed at sinus rhythm and some during a different ventricular-paced cycle length. The difference between this study and our data43 probably relates to the fact that we could not compare very slow rates with faster rates and only studied rates of 100 and 150 bpm in detail. Moreover, the effect of chronic bradycardia and subsequent ventricular enlargement may play an important role in refractory period measurements. Other workers have looked at the effect of site of pacing on refractoriness, considering, for example, whether atrial pacing differed from ventricular pacing. In contrast, when we compared dispersion of refractoriness and recovery from multiple left ventricular sites measured during atrial pacing and ventricular pacing at the stimulation site in five patients, we found no significant difference in dispersion of refractory periods of total recovery times. The difference between these results is unclear, although the small number of pacing sites in the study by Friehling et al. Our data on normal left ventricular dispersion of refractoriness and total recovery time serve as a reference for evaluating the role of dispersion refractoriness and/or recovery in arrhythmogenesis. The signals recorded are quite comparable to intracellular microelectrode recording, and if properly done are stable for a few hours. Thus, the value of this technique in abnormal tissue or in the presence of Na channel blockers is uncertain. Patterns of Response to Atrial Extrastimuli Several patterns of response to programmed atrial extrastimuli are characterized by differing sites of conduction delay and block and the coupling intervals at which they occur. Although it has been stated that any prolongation of His–Purkinje conduction is an abnormal response, it is not. Previous studies demonstrated that 15% to 60% of normal patients can show some prolongation of the H-V interval in response to atrial extrastimuli. Thus, block below the His bundle in response to an atrial extrastimulus delivered during sinus rhythm may be a normal response. The curves may be drawn in two ways: (a) by plotting A1-A2 versus H1-H2 and V1-V, which gives the functional input–output relationship between the basic drive beat and the premature beat, and (b) by plotting the actual conduction times of the premature beat through the A-V node (A2-H2) and His–Purkinje system (H1-V2) versus the A1-A2 intervals. A2-H2 and H2-V2) allows a purer evaluation of the response to A2 because, unlike the former curve, the results are not affected by conduction of the basic drive beat. This becomes particularly important when the effects of drugs or cycle length on the conduction of premature atrial impulses are being evaluated. During this limited decrease, A-V nodal conduction (A2-H2) and His–Purkinje conduction (H2-V2) are unchanged from the basic drive so that the curve moves along the line of identity. The H1-H2 and V1-V2 curves remain identical, localizing the delay to the A-V node, as shown in the right-hand panel as an increase in the A2-H2 interval without any change in the H2-V2. The curve continues to descend at a decreasing slope as further A-V nodal delay is encountered. At a critical Al-A2 interval, the delay in the A-V node becomes so great that the H1-H2 and V1-V2 intervals begin to increase. The increase in H1-H2 and V1-V2 continues until the impulse is blocked within the A-V node or until atrial refractoriness is reached. A-V nodal conduction (A2-H2) usually is prolonged two to three times control values before A-V nodal block. If the increment in H2-V2 approximates the decrement in A1-A2, V1-V2 assumes a relatively fixed value, producing a horizontal limb. At longer coupling intervals, conduction is unchanged and the curve decreases along the line of identity. Further shortening, however, produces a sudden jump in the H2-V2 interval, resulting in a break in the V1-V2 curve, which subsequently descends until, at a critical Al-A2 interval, the impulse usually blocks within the A-V node or His–Purkinje system. Aberrant conduction invariably accompanies beats with prolonged His–Purkinje conduction times. Again, autonomic tone at the time of catheterization can markedly affect the percentage of patients whose A-V nodes have the longest refractory periods during antegrade stimulation. The cycle lengths at which these refractory period measurements were made were highly variable, and inconsistent use of sedation, I believe, explains the disparate results. Patterns of Response to Ventricular Extrastimuli Retrograde conduction has been less well characterized than antegrade conduction. In patients with A-V dissociation, we employ simultaneous atrial and ventricular pacing during the basic drive to prevent supraventricular captures from altering refractoriness by producing sudden changes in cycle length. Moreover, potential changes in hemodynamics related with A-V dissociation may also affect the reproducibility of refractory period studies. Thus, attention should be given to ensuring a constant 1:1 relationship between ventricular pacing and atrial activation. Similar stimulation methods must be used, therefore, when drug effects or other interventions are to be compared. Although the functional properties of conduction and refractoriness follow principles similar to those of antegrade studies, the most common site of retrograde delay and block is in the His–Purkinje system. Detailed assessment of retrograde conduction was limited in the past by the fact that the His bundle deflection was not uniformly observed during the basic drive, thus making the cases reported relatively selected. More recently, using bipolar electrodes with a 5-mm interelectrode distance and being extremely careful, we have been able to record retrograde His deflections during the ventricular-paced drive in up to 85% of our patients. A second limiting factor is that during ventricular extrastimuli the His deflection can be buried within the ventricular electrogram over a wide range of ventricular coupling intervals, therefore making measurements of ventricle to His bundle conduction times impossible in these circumstances. This technique, although not widely used, offers the best method of evaluating retrograde His–Purkinje conduction during programmed ventricular stimulation. Since a retrograde His potential may not be observed even at close coupling intervals in approximately 15% to 20% of patients using standard techniques (pacing the right ventricular apex), evaluation of His–Purkinje and consequently A-V nodal conduction is at best incomplete. The rationale for choosing S1-H2 is the observation in animals and in occasional patients that over a wide range of ventricular-paced rates, S1-H1 remains constant (Figs. The typical response shown in Figures 2-43 and 2-44 may be graphically displayed by plotting S1-S2 versus P. As noted, the ability to record a retrograde His deflection during the basic drive greatly facilitates analyzing the location of conduction delays and block.
