to investigate the relationship between prolonged qt interval and maternal smoking research done by:...
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![Page 1: To Investigate the Relationship Between Prolonged QT Interval and Maternal Smoking Research Done by: Bindu Punnoose Mentor: Dr. Michael Myers, Ph.D. Columbia](https://reader036.vdocuments.us/reader036/viewer/2022082917/5513c82855034674748b48b1/html5/thumbnails/1.jpg)
To Investigate the Relationship Between Prolonged QT Interval
and Maternal Smoking
Research Done by: Bindu Punnoose
Mentor: Dr. Michael Myers, Ph.D.
Columbia Presbyterian Medical Center
![Page 2: To Investigate the Relationship Between Prolonged QT Interval and Maternal Smoking Research Done by: Bindu Punnoose Mentor: Dr. Michael Myers, Ph.D. Columbia](https://reader036.vdocuments.us/reader036/viewer/2022082917/5513c82855034674748b48b1/html5/thumbnails/2.jpg)
Review of Literature
• Moss AJ, Schwartz PJ: Delayed Repolarization (QT or QT-U prolongation) and Malignant Ventricular Arrhythmias. Mod. Concepts Cardiovascular Dis 1982
• Schwartz PJ, Montemerio M, et al: The QT Interval Throughout the First Six Months of Life Circulation 1982
• Malloy MH, Kleinman JC, Land GH, et al: The Association of Maternal Smoking With Age and Cause of Infant Death Am. J. of Epid. 1988
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Review of Literature (..cont’d)
• Milerad J, Sundell H: Nicotine Exposure and Risk of SIDS Acta. Paediatr. Suppl. 1993
• Schwartz PJ, et al: Prolongation of the QT Interval and the Sudden Infant Death Syndrome The New England Journal of Medicine 1998
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Hypothesis
• A relationship exists between prolonged QT interval in infants and maternal smoking
![Page 5: To Investigate the Relationship Between Prolonged QT Interval and Maternal Smoking Research Done by: Bindu Punnoose Mentor: Dr. Michael Myers, Ph.D. Columbia](https://reader036.vdocuments.us/reader036/viewer/2022082917/5513c82855034674748b48b1/html5/thumbnails/5.jpg)
Materials and Methods• Electrocardiograms of 24 infants (12 males
12 females) all 2 months old analyzed
• 17 babies from rural Native American population
• 7 babies from urban population in New York City
• All infants healthy at birth with apgar scores greater than 8
• Smoking habits of mothers obtained via questionnaire given at beginning of study
![Page 6: To Investigate the Relationship Between Prolonged QT Interval and Maternal Smoking Research Done by: Bindu Punnoose Mentor: Dr. Michael Myers, Ph.D. Columbia](https://reader036.vdocuments.us/reader036/viewer/2022082917/5513c82855034674748b48b1/html5/thumbnails/6.jpg)
Materials and Methods (..cont’d)• Babies selected by means of availability,
good health, and no other risk factor (maternal alcohol consumption, low birth weight, difficult pregnancy)
• ECG’s taken during baseline period of previous study were amplified and collected onto VCR tapes
• Data from tapes digitized at 500 samples/sec and transformed into plottable wave forms
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Materials and Methods (..cont’d)
• ECG’s of each baby marked at Q, R1, R2, and T segments using special purpose software programs for 25 intervals per baby
• Intervals measured in milliseconds, times recorded into SYSTAT
• QT adjusted for heartrate using Bazette’s formula: QTc= (Q-T)/ (R2-R1)
• Average QTc’s were found
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Materials and Methods (..cont’d)
• QTc’s analyzed using SYSTAT
• Statistical analyses performed: t test for paired and unpaired observations
• Relationships looked for between QTc interval and maternal smoking
• Factors such as birth weight, sex, and maternal age also tested
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Results• The mean QTc for all cases was 399+/- 26
msec
• Smoking during pregnancy did not affect QTc interval
• Sex and birthweight did not affect QTc interval
• Maternal age affected QTc interval
– Infants divided into 2 groups:
– “old” mothers >25 years of age– “young” mothers <25 years of age
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Results (..cont’d)
• Infants with mothers classified as “young” had significantly longer QTc’s than infants with “old” mothers (t(23)=2.11, p<.05)
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Discussion• As further supported by this study, QT
interval of infants should be researched more thoroughly
• Since prolonged QT interval is mostly thought to be genetically based and the extreme of a normal distribution, risk may be quantitatively related to length; factors affecting length could alter risk
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Discussion (..cont’d)• Environmental contributions such as maternal
age could give infants at risk the extra push needed for prolonged QT interval to occur
• Perhaps young mothers have sub-optimal in-utero environments, making their infants prone to such a syndrome
• Controversy exists as to whether ECG’s should be done on all infants. This would be costly and can have clinical implications