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Direct current cardioversion during pregnancy
CORRESPONDENCE
Reference 1. Stovall TG, Summitt Jr RL, Washburn SA, Ling FW. Gonadotropinreleasing hormone agonist use before hysterectomy. Am J Obstet Gynecol 1994;170:1744 – 1751.
Cynthia Farquhar The University of Auckland, Auckland, New Zealand PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 3 0 0 0 3 - 5
Meconium and fetal hypoxia : some experimental observations and clinical relevance Sir, We read the article ‘Meconium and fetal hypoxia: some experimental observations and clinical relevance’1 with interest. The authors find that, in an experimental situation, acute hypoxia is not associated with passage of meconium, but that chemical sympathectomy followed by hypoxia always resulted in meconium-stained amniotic fluid. They suggest that another event is required to stimulate the passage of meconium, namely, a reduction in neural sympathetic tone. They also conclude that their experimental data and the available literature do not support a direct association between meconium-stained amniotic fluid and acute hypoxia. Although their data are noteworthy, there were only eight fetal lambs in the control arm of the experiment. A direct association could have been missed if passage of meconium is rare in normal lambs or if, despite a direct causal association, it does not happen in every hypoxic lamb. In our recent study of 8394 low risk labouring women with clear amniotic fluid at early amniotomy2, we found that meconium passage in labour occurred in only 435 (5.2%) cases. Despite this, there was clear evidence of an association between moderate or severe acidosis at birth (arterial pH < 7.05 or venous pH < 7.12 or base deficit > 12) and meconium passage: OR 4.33, 95% CI 3.17 – 5.93. Nevertheless, 247/300 (82.3%) of babies born acidotic did not develop meconium-stained amniotic fluid in labour. The clinical implication of this finding is that, although meconium-stained amniotic fluid is related to increased perinatal morbidity, the identification of clear amniotic fluid cannot be taken to be reassuring about the fetal acid – base status, or other even worse outcomes. Westgate et al.’s data1 may explain why this is so.
713
Endometrial abnormalities in three sisters from a family with hereditary non-polyposis colorectal cancer syndrome Sir, I read with interest the article by Baxter et al.1 concerning the investigation and treatment of women with hereditary non-polyposis colorectal cancer syndrome at high risk of endometrial cancer. They advocate screening with endometrial aspiration and transvaginal ultrasound, and criticise prophylactic surgery in later life. I agree that endometrial biopsy and transvaginal ultrasound are probably very good methods of screening for endometrial pathology in such women, but I feel that pelvic surgery should not be entirely dismissed. Firstly, it is important to realise that hereditary non-polyposis colorectal cancer syndrome carries with it a much higher chance of ovarian neoplasia as well as a high risk for endometrial cancer. It has been estimated that about 9% of women with hereditary non-polyposis colorectal cancer syndrome will develop ovarian cancer2. The mean age at presentation is 43 years, about 15 years less than for sporadic cases, and 8 years before the average age of the menopause3. There is no evidence that ultrasound screening for ovarian cancer reduces the risk of death from that disease. A second point concerns particular characteristics of individual women, where outpatient endometrial sampling might prove impossible because of cervical stenosis, or is poorly tolerated. Prophylactic surgery is not without its problems but it might be more acceptable to some women. I suggest that women should be given this option.
References 1. Baxter NP, Duffy SRG, Sheridan E. Endometrial abnormalities in three sisters from a family with hereditary non-polyposis colorectal cancer syndrome. Br J Obstet Gynaecol 2002;109:671 – 677. 2. Watson P, Lynch HT. Extracolonic cancer in HNPCC. Cancer 1993;71:677 – 685. 3. Marra G, Boland CR. Hereditary nonpolyposis colorectal cancer syndrome. J Natl Cancer Inst 1995;87:1114 – 1125.
Robert Fox Department of Obstetrics and Endocrinology, Taunton & Somerset Hospital, Taunton, UK PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 5 - 9
Direct current cardioversion during pregnancy References 1. Westgate JA, Bennet L, Gunn AJ. Meconium and fetal hypoxia: some experimental observations and clinical relevance. Br J Obstet Gynaecol 2002;109:1171 – 1174. 2. Lalchandani S, Greenwood C, MacQuillan K, Sheil O, Murphy J, Impey L. Meconium passed in labour. Presented at BAPM/BMFMS Joint Meeting, Reading University, 2002 (September).
Mona Zaki, Catherine Greenwood & Lawrence Impey Oxford Feto-maternal Medicine Unit, John Radcliffe Hospital, Headington, Oxford, UK PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 1 - 1
D RCOG 2003 Br J Obstet Gynaecol 110, pp. 710 – 714
Sir, The article by Barnes et al.1 concluded that direct current cardioversion had led to a sustained uterine contraction and severe fetal distress. Clinicians should be aware of two recent developments that reduce both the energy requirement and the risk of complication2. Firstly, a rectilinear biphasic shock waveform is more effective than the standard monophasic sinusoidal waveform3. Secondly, internal cardioversion, using either single or dual catheters with shocking electrodes in the superior vena cava or right atrium and the pulmonary artery or coronary sinus, allows the local delivery of a shock across the atria4. With this configuration cardioversion can usually be achieved with 5 – 10 J, approximately 10% of the energy requirement for external cardioversion, although it requires access to a central vein and a
714
CORRESPONDENCE
small amount of radiographic screening. These two options should be strongly considered in the future.
References 1. Barnes EJ, et al. Direct current cardioversion during pregnancy should be performed with facilities available for fetal monitoring and emergency caesarean section. Br J Obstet Gynaecol 2002;109:1406 – 1407. 2. Brown O, Davidson N, Palmer J. Cardioversion in the third trimester of pregnancy. Aust N Z J Obstet Gynaecol 2001;41:241 – 242.
3. Mittal S, Ayati S, Stein K. Transthoracic cardioversion of atrial fibrillation. Circulation 2000;101:1282 – 1287. 4. Boriani G, Biffi M, Pergolini F. Low energy atrial cardioversion in atrial fibrillation lasting more than one year. Pacing Clin Electrophysiol 1999;22:243 – 246.
Oliver Brown Department of Obstetrics and Gynaecology, John Hunter Hospital, Australia PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 7 - 2
D RCOG 2003 Br J Obstet Gynaecol 110, pp. 710 – 714
Reference 1. Stovall TG, Summitt Jr RL, Washburn SA, Ling FW. Gonadotropinreleasing hormone agonist use before hysterectomy. Am J Obstet Gynecol 1994;170:1744 – 1751.
Cynthia Farquhar The University of Auckland, Auckland, New Zealand PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 3 0 0 0 3 - 5
Meconium and fetal hypoxia : some experimental observations and clinical relevance Sir, We read the article ‘Meconium and fetal hypoxia: some experimental observations and clinical relevance’1 with interest. The authors find that, in an experimental situation, acute hypoxia is not associated with passage of meconium, but that chemical sympathectomy followed by hypoxia always resulted in meconium-stained amniotic fluid. They suggest that another event is required to stimulate the passage of meconium, namely, a reduction in neural sympathetic tone. They also conclude that their experimental data and the available literature do not support a direct association between meconium-stained amniotic fluid and acute hypoxia. Although their data are noteworthy, there were only eight fetal lambs in the control arm of the experiment. A direct association could have been missed if passage of meconium is rare in normal lambs or if, despite a direct causal association, it does not happen in every hypoxic lamb. In our recent study of 8394 low risk labouring women with clear amniotic fluid at early amniotomy2, we found that meconium passage in labour occurred in only 435 (5.2%) cases. Despite this, there was clear evidence of an association between moderate or severe acidosis at birth (arterial pH < 7.05 or venous pH < 7.12 or base deficit > 12) and meconium passage: OR 4.33, 95% CI 3.17 – 5.93. Nevertheless, 247/300 (82.3%) of babies born acidotic did not develop meconium-stained amniotic fluid in labour. The clinical implication of this finding is that, although meconium-stained amniotic fluid is related to increased perinatal morbidity, the identification of clear amniotic fluid cannot be taken to be reassuring about the fetal acid – base status, or other even worse outcomes. Westgate et al.’s data1 may explain why this is so.
713
Endometrial abnormalities in three sisters from a family with hereditary non-polyposis colorectal cancer syndrome Sir, I read with interest the article by Baxter et al.1 concerning the investigation and treatment of women with hereditary non-polyposis colorectal cancer syndrome at high risk of endometrial cancer. They advocate screening with endometrial aspiration and transvaginal ultrasound, and criticise prophylactic surgery in later life. I agree that endometrial biopsy and transvaginal ultrasound are probably very good methods of screening for endometrial pathology in such women, but I feel that pelvic surgery should not be entirely dismissed. Firstly, it is important to realise that hereditary non-polyposis colorectal cancer syndrome carries with it a much higher chance of ovarian neoplasia as well as a high risk for endometrial cancer. It has been estimated that about 9% of women with hereditary non-polyposis colorectal cancer syndrome will develop ovarian cancer2. The mean age at presentation is 43 years, about 15 years less than for sporadic cases, and 8 years before the average age of the menopause3. There is no evidence that ultrasound screening for ovarian cancer reduces the risk of death from that disease. A second point concerns particular characteristics of individual women, where outpatient endometrial sampling might prove impossible because of cervical stenosis, or is poorly tolerated. Prophylactic surgery is not without its problems but it might be more acceptable to some women. I suggest that women should be given this option.
References 1. Baxter NP, Duffy SRG, Sheridan E. Endometrial abnormalities in three sisters from a family with hereditary non-polyposis colorectal cancer syndrome. Br J Obstet Gynaecol 2002;109:671 – 677. 2. Watson P, Lynch HT. Extracolonic cancer in HNPCC. Cancer 1993;71:677 – 685. 3. Marra G, Boland CR. Hereditary nonpolyposis colorectal cancer syndrome. J Natl Cancer Inst 1995;87:1114 – 1125.
Robert Fox Department of Obstetrics and Endocrinology, Taunton & Somerset Hospital, Taunton, UK PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 5 - 9
Direct current cardioversion during pregnancy References 1. Westgate JA, Bennet L, Gunn AJ. Meconium and fetal hypoxia: some experimental observations and clinical relevance. Br J Obstet Gynaecol 2002;109:1171 – 1174. 2. Lalchandani S, Greenwood C, MacQuillan K, Sheil O, Murphy J, Impey L. Meconium passed in labour. Presented at BAPM/BMFMS Joint Meeting, Reading University, 2002 (September).
Mona Zaki, Catherine Greenwood & Lawrence Impey Oxford Feto-maternal Medicine Unit, John Radcliffe Hospital, Headington, Oxford, UK PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 1 - 1
D RCOG 2003 Br J Obstet Gynaecol 110, pp. 710 – 714
Sir, The article by Barnes et al.1 concluded that direct current cardioversion had led to a sustained uterine contraction and severe fetal distress. Clinicians should be aware of two recent developments that reduce both the energy requirement and the risk of complication2. Firstly, a rectilinear biphasic shock waveform is more effective than the standard monophasic sinusoidal waveform3. Secondly, internal cardioversion, using either single or dual catheters with shocking electrodes in the superior vena cava or right atrium and the pulmonary artery or coronary sinus, allows the local delivery of a shock across the atria4. With this configuration cardioversion can usually be achieved with 5 – 10 J, approximately 10% of the energy requirement for external cardioversion, although it requires access to a central vein and a
714
CORRESPONDENCE
small amount of radiographic screening. These two options should be strongly considered in the future.
References 1. Barnes EJ, et al. Direct current cardioversion during pregnancy should be performed with facilities available for fetal monitoring and emergency caesarean section. Br J Obstet Gynaecol 2002;109:1406 – 1407. 2. Brown O, Davidson N, Palmer J. Cardioversion in the third trimester of pregnancy. Aust N Z J Obstet Gynaecol 2001;41:241 – 242.
3. Mittal S, Ayati S, Stein K. Transthoracic cardioversion of atrial fibrillation. Circulation 2000;101:1282 – 1287. 4. Boriani G, Biffi M, Pergolini F. Low energy atrial cardioversion in atrial fibrillation lasting more than one year. Pacing Clin Electrophysiol 1999;22:243 – 246.
Oliver Brown Department of Obstetrics and Gynaecology, John Hunter Hospital, Australia PII: S 1 4 7 0 - 0 3 2 8 ( 0 3 ) 0 3 8 0 7 - 2
D RCOG 2003 Br J Obstet Gynaecol 110, pp. 710 – 714