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Biomedical subjects

K Monahan

Publications and source records attributed to K Monahan.

At least 19 recordsLinked to original sources
PubMed2005

Warfarin induction at 5 mg daily is safe with a low risk of anticoagulant overdose: results of an audit of patients with deep vein thrombosis commencing warfarin.

BACKGROUND: Conventionally warfarin therapy is initiated using a loading dose given over several days. Daily international normalised ratio (INR) monitoring is recommended to prevent overdose; however, with a large proportion of patients with deep vein thrombosis now receiving treatment out of hospital daily blood tests are inconvenient. We introduced a low-dose protocol for starting anticoagulant therapy that only required INR testing on days 4 and 6 and audited the results to assess safety and efficacy. METHODS: Two-hundred and forty-eight patients with confirmed deep vein thrombosis were started on warfarin therapy at 5 mg daily for 3 days. INR measurements were taken at day 4 and day 6. RESULTS: Of these patients, 21% had an INR within the therapeutic range on day 4 and 52% had a therapeutic INR on day 6. The risk of overdose was small with only one case with an INR above 4.0 on day 4 and nine cases on day 6. There were no reported cases of bleeding. CONCLUSION: The low-dose protocol with infrequent testing is safe and convenient for outpatient management. However, our results suggest that patients on this protocol take between 6-10 days to achieve a stable INR.

Adolescent↗
PubMed2001

The rapid whole blood agglutination d-dimer assay has poor sensitivity for use as an exclusion test in suspected deep vein thrombosis.

AIMS: Several clinical studies have proposed using d-dimer as an initial screening test to exclude thrombosis in cases of suspected (DVT). In published series, these assays have variable sensitivity, raising concerns that they may not be sufficiently robust for clinical practice. The aim of the study was to examine the sensitivity of two commercially available d-dimer assays and to assess their value and safety as initial screening tests in suspected DVT. METHODS: In this prospective study, blood samples were collected for d-dimer measurement (SimpliRED assay and IL test d-dimer) in all patients presenting to the emergency department over a twelve month period. All patients underwent compression ultrasound scanning as the primary diagnostic procedure. RESULTS: 235 patients were included in the study. 51(22.8%) had a DVT confirmed on ultrasound. The SimpliRED assay was positive in only 33 cases, with seventeen cases of confirmed DVT giving a negative result (six cases with proximal vein thrombosis). Assay sensitivity was 66%, with a negative predictive value of 88.9%. The IL test gave three false negatives (all below knee thromboses) giving assay sensitivity and negative predictive value of 94.1% and 96.8% respectively. CONCLUSIONS: The precise role of d-dimer testing in the diagnosis of venous thrombosis has yet to be established. From our results and a review of published series, we conclude that the SimpliRED assay is too insensitive to use as a reliable exclusion test in cases of suspected DVT, however, the more sensitive automated IL test d-dimer may have a role in the initial assessment. We propose that the IL d-dimer test is used in conjunction with a pre-test probability score to identify patients at low risk of DVT and recommend that this approach is tested in a clinical study before introduction into practice.

Diagnosis, Differential↗
PubMed2001

Prevention principles for practitioners: a solution or an illusion?

The social work profession has sought to eliminate, or at the very least, ameliorate those social ills that were believed to contribute to severe social and personal dysfunction. Prevention programs have been a primary factor in this endeavor. Prevention programs have addressed a vast array of difficulties including adolescent suicide, youth violence, teenage pregnancy, home visiting programs for families at high-risk for neglect and abuse as well as out-of-home placement. This paper addresses the concept of prevention and incorporates the notion of resilience in eight (8) prevention practice principles. Case examples are provided as well as a discussion for future directions for prevention in the field of social work.

Adult↗
PubMed2000

Shifts in membrane fatty acid profiles associated with acid adaptation of Streptococcus mutans.

Cells of Streptococcus mutans UA159 physiologically adapted to acidification during growth at pH 5 in glucose-limited chemostat cultures were enriched in mono-unsaturated and longer chain fatty acids compared with unadapted cells grown under the same conditions but at pH 7. Ratios of unsaturated to saturated fatty acids in the cells were, respectively, 1.2 and 0.3. Cyclopropane fatty acids were not detected. Streptococcus sobrinus 6715, which is known to have minimal acid-adaptive capacity, showed only minimal change in membrane fatty acids.

Adaptation, Physiological↗
PubMed2000

Air pollution and incidence of cardiac arrhythmia.

Air pollution episodes have been associated with increased cardiovascular hospital admissions and mortality in time-series studies. We tested the hypothesis that patients with implanted cardioverter defibrillators experience potentially life-threatening arrhythmias after such air pollution episodes. We compared defibrillator discharge interventions among 100 patients with such devices in eastern Massachusetts, according to variations in concentrations of particulate matter, black carbon, and gaseous air pollutants that were measured daily for the years 1995 through 1997. A 26-ppb increase in nitrogen dioxide was associated with increased defibrillator interventions 2 days later (odds ratio = 1.8; 95% confidence interval = 1.1-2.9). Patients with ten or more interventions experienced increased arrhythmias in association with nitrogen dioxide, carbon monoxide, black carbon, and fine particle mass. These results suggest that elevated levels air pollutants are associated with potentially life-threatening arrhythmia leading to therapeutic interventions by an implanted cardioverter defibrillator.

Adult↗
PubMed2000

Enhancing the health care experiences of adult female survivors of childhood sexual abuse.

This article addresses the medical issues presented by women who were sexually abused in childhood and provides a detailed and direct link between the existing literature and its implications for the medical system. A profile of the sexual abuse survivor is given, including child sexual abuse (CSA) characteristics and sequelae that influence the adult female survivor's health. Post-traumatic Stress Disorder is outlined as part of a complex interplay of physiological and psychological symptomatology that can compromise the CSA survivor's ability to access health care treatment and forge a positive provider/patient relationship. This article emphasizes that effective treatment with sexual abuse survivors must include interdisciplinary collaboration among health care professionals. Management of the CSA patient, a case vignette illustrating salient themes, and finally, guidelines for the health care practitioner are presented.

Adult↗
PubMed1999

Presence and significance of the left atrionodal connection during atrioventricular nodal reentrant tachycardia.

It has been suggested that the anatomic substrates of dual atrioventricular nodal pathways are likely to be the atrionodal connections. During atrioventricular nodal re-entrant tachycardia (AVNRT) or ventricular pacing (VP), an earliest retrograde atrial activation in the coronary sinus (CS) distal to the ostium (CS breakthrough) would suggest the presence of an exit from a left atrionodal connection. The aim of the study was to evaluate the incidence of such an atrial retrograde activation in the CS during AVNRT and VP. The retrograde atrial activation was recorded during typical AVNRT (38 patients, 27 women, mean age 44 +/- 18 years) by a multipolar catheter in the CS, a decapolar catheter in the His bundle position, and a deflectable quadripolar catheter along the tricuspid annulus anterior to the CS ostium. In 31 patients the retrograde atrial activation was recorded also during VP at a similar cycle length. A CS breakthrough was found in 18 patients during AVNRT (47%) and in 13 patients during VP (42%). Presence or absence of CS breakthrough was concordant between AVNRT and VP in 90% of the patients. A CS breakthrough, suggesting a left-sided atrionodal connection, is frequently recorded both during AVNRT and VP. In patients with a CS breakthrough pattern, the absence of correlation between the His bundle to the earliest CS retrograde atrial electrogram interval and AVNRT cycle length, or any other atrial activation times recorded in the posterior and anterior region of the Koch's triangle, would suggest that the left-sided atrionodal connection is a bystander during typical AVNRT.

Adolescent↗
PubMed1999

Entrainment/mapping criteria for the prediction of termination of ventricular tachycardia by single radiofrequency lesion in patients with coronary artery disease.

BACKGROUND: A variety of mapping criteria have been proposed to localize critical sites at which radiofrequency (RF) can predictably terminate reentrant ventricular tachycardia (VT) caused by coronary artery disease. The purpose of this study was to determine the accuracy of using a combination of 3 mapping criteria in predicting termination of VT by a single RF lesion. METHODS AND RESULTS: Fifteen consecutive patients with coronary artery disease and recurrent sustained VT underwent an attempted RF ablation of 20 monomorphic VTs. Successful termination of VT by a single RF lesion was predicted if all the following mapping criteria were met: (1) an exact QRS match in the 12-lead ECG during entrainment; (2) a return cycle length </=10 ms of the VT cycle length; (3) presystolic potentials (<70% of VT cycle length) with an activation time to the QRS within 10 ms of the stimulus to QRS. Inability to meet these 3 criteria was considered to predict failure of VT termination by RF energy at that site. RF ablation was applied to 44 left ventricular sites in 20 VTs at which at least 1 of the mapping criteria was met. VT was terminated with a single RF lesion in 19 of 19 sites meeting all criteria; RF failed to terminate VT at 24 of 25 sites at which all 3 criteria were not met (P<0.0005). CONCLUSIONS: To maximize success and minimize the number of RF lesions in patients with infarct-related VT, all the above 3 mapping criteria should be met before the application of RF energy.

Adult↗
PubMed1999

Head injury and battered women: an initial inquiry.

Approximately 2 to 3 million women are battered by their intimate partners each year. Severe injuries requiring emergency medical treatment of battered women have been noted, yet the prevalence of head injuries and the negative consequences emanating from such injuries have been noticeably absent from the literature. The descriptive study discussed in this article examined the case records of residents in a domestic violence shelter over a three-month period and found a 35 percent prevalence rate of battered women who had experienced head injury during a battering incident with their intimate partner. This study calls attention to the long-range difficulties that head-injured battered women may experience as a result of cognitive, emotional, and behavioral difficulties resulting from domestic violence and how social workers can intervene with this population.

Adult↗
PubMed1998

Combined use of a true-bipolar sensing implantable cardioverter defibrillator in a patient having a prior implantable spinal cord stimulator for intractable pain.

Reported is a case involving a patient with a previously implanted spinal cord stimulator (SCS) who presented for an implantable cardioverter defibrillator (ICD). The SCS device was located in the left lower abdominal quadrant with a stimulation electrode array placed on the dorsal aspect of the spinal cord at the T-11 thoracic level. Interaction testing demonstrated that the biopolar sensing transvenous ICD system (Medtronic 7221 Cx PCD) did not detect the stimulator's output at burst rates ranging from 20-130 pulses/s, even with the ICD set to its maximum sensitivity of 0.15 m V and the stimulator programmed to the highest patient tolerated output combinations of 5 V, 0.45 ms in the bipolar configuration and 3 V, 0.45 ms in the unipolar (i.e., case-electrode) configuration.

Aged↗
PubMed1997

Coronary sinus pacing prevents induction of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is due to reentry, and its incidence has been shown to decrease after dual-site atrial or biatrial pacing. We investigated whether a simpler pacing approach via the distal coronary sinus (CSd) could eliminate AF inducibility by high right atrial (HRA) extrastimuli (APDs). We based our hypothesis on our previous observation that AF inducibility by HRA APDs was associated with conduction delays to the posterior triangle of Koch, whereas AF was never induced with CSd APDs, which were associated with minimal intra-atrial conduction delays. METHODS AND RESULTS: Programmed electrical stimulation was performed from the high right atrium and CSd, and bipolar recordings were obtained from the high right atrium, His bundle, posterior triangle of Koch, and coronary sinus. In 13 patients (age, 44+/-18 years), AF was reproducibly induced with a critically timed HRA APD (220+/-22 ms) delivered during HRA pacing. AF was not induced in any of the patients when HRA APDs were delivered during CSd pacing at the same critical coupling intervals. Coronary sinus APDs delivered during HRA pacing also were not associated with AF induction. The APD coupling interval measured at the posterior triangle of Koch during CSd pacing was significantly prolonged compared with the one measured during HRA pacing and AF induction (381+/-58 versus 263+/-37 ms; P<.0001). CONCLUSIONS: We propose that CSd pacing suppresses the propensity of HRA APDs to induce AF by limiting their prematurity at the posterior triangle of Koch and not allowing local conduction delay and local reentry to occur.

Adolescent↗
PubMed1997

Origin of junctional rhythm during radiofrequency ablation of atrioventricular nodal reentrant tachycardia in patients without structural heart disease.

Junctional rhythm is commonly observed during radiofrequency catheter ablation of the fast or slow pathways of atrioventricular nodal reentrant tachycardia (AVNRT). However, the origin of these beats remains unclear. We analyzed the retrograde atrial activation sequence of 16 patients (mean +/- SD: 41.2 +/- 18.9 years old) undergoing catheter ablation for typical AVNRT with detailed catheter mapping of the triangle of Koch. The earliest atrial activations were concordant during tachycardia and junctional rhythm in only 5 of 16 patients. The findings suggest that junctional rhythm is unlikely to represent direct stimulation of the atrioventricular (AV) node via a discrete slow pathway but rather results from enhanced automaticity from > or =1 sites in the AV nodal transitional zone. The ensuing atrial activation pattern results from anisotropic spread from these sites. In addition, these data imply that the original concept of the AV node comprising 2 anatomically defined pathways may not be valid, and that a functionally defined pathway model may be a more accurate representation.

Adolescent↗
PubMed1997

Crocodile talk: attributions of incestuously abused and nonabused sisters.

This study is a qualitative analysis of the attributions of sisters (abused and nonabused sister dyads, n = 10 and abused sister dyads, n = 10) who grew up in an incestuous family. While the sibling subsystem is reported to be the most important and enduring relational environment in the life of the family, little is known about the cognitions and attributions of siblings, regarding incest. This study examines the attributions of participants regarding the general sibling group, victim selection and nonselection, as well as attributions regarding jealousy, protection, and guilt within the sister relationship.

Adaptation, Psychological↗
PubMed1997

Inadequacy of qualitative implantable cardioverter defibrillator electrogram analysis to distinguish supraventricular from ventricular tachycardia due to electrogram changes during normally conducted complexes.

Stored electrograms (EGMs) recorded from ICD leads are used to evaluate the appropriateness of ICD therapies. Stored EGMs different from sinus have been interpreted as ventricular in origin. We present a patient with an ICD for VT who received multiple shocks for a tachycardia with a stored EGM different than sinus, suggesting VT. An electrophysiological study demonstrated EGMs different than sinus during atrial pacing and induced supraventricular arrhythmias. This case points out the limitations of stored EGMs and suggests complete electrophysiological study with analysis of EGMs during induced arrhythmias should be performed prior to discharge.

Cardiac Pacing, Artificial↗
PubMed1997

Electrophysiology of atrial fibrillation and its prevention by coronary sinus pacing.

Atrial fibrillation (AF) is a re-entrant rhythm, and patients with AF have intra-atrial conduction abnormalities as evidenced by prolonged P-wave duration, abnormal SAECG of P wave, fragmented atrial electrograms and greater intra-atrial conduction delays in response to APDs. Our previous work has proposed that intra-atrial conduction delays and dispersion of refractoriness during extrastimulus testing are site dependent; high right atrial (HRA) stimulation results in marked prolongation of intra-atrial conduction times and AF, whereas distal coronary sinus (CS) stimulation is associated with minimal conduction delays and absence of AF inducibility. Patients with AF induction during HRA stimulation also manifest non-uniform anisotropic conduction in the region of the posterior triangle of Koch. We postulated that if the posterior triangle of Koch is a critical area for re-entry that initiates AF, then prevention of early activation of the posterior triangle may prohibit AF induction by HRA APDs. Distal CS pacing pre-excites the posterior triangle in relation to HRA activation, therefore a subsequent HRA APD will activate the posterior triangle with a longer coupling interval. AF induction by HRA APDs following HRA pacing is prevented when same HRA APDs follow distal CS pacing. We propose that distal CS pacing eliminates the propensity of HRA extrasystoles to induce AF. This observation may have further clinical applicability in AF prevention.

Atrial Fibrillation↗
PubMed1996

Site-dependent intra-atrial conduction delay. Relationship to initiation of atrial fibrillation.

BACKGROUND: Atrial dysrhythmia patients have exaggerated intra-atrial conduction delays and prolonged relative refractoriness in response to atrial premature depolarizations (APDs). Furthermore, atrial fibrillation (AF) is more readily inducible by APDs from the high right atrium (HRA) than the coronary sinus (CS). In this study, we postulated that site-specific intra-atrial conduction delays can explain why AF is initiated more from the HRA than from the CS. METHODS AND RESULTS: We examined 17 patients (age, 49 +/- 22 years) without a history of atrial flutter, AF, or structural heart disease. Programmed stimulation was carried out from the HRA and distal CS, and bipolar recordings were made at the HRA, His bundle, posterior triangle of Koch, and CS. More prolongations in conduction and relative refractoriness in all intra-atrial sites were observed during HRA than CS APDs. AF was induced in 8 patients after HRA and not CS stimulation. During HRA stimulation, patients with AF inducibility exhibited significant prolongation of conduction to the posterior triangle of Koch and marked broadening of the posterior triangle of Koch electrogram compared with CS stimulation. In patients without AF inducibility, the posterior triangle of Koch electrogram width was the same during HRA and CS stimulation. CONCLUSIONS: The existence of site-dependent intra-atrial conduction delays and site-dependent dispersion of refractoriness appears to be a common property of the atrial myocardium and does not necessarily forecast AF inducibility. However, the presence of nonuniform anisotropic characteristics of the posterior triangle of Koch may be critical for AF induction.

Adult↗
PubMed1996

Heterogeneity of retrograde fast-pathway conduction pattern in patients with atrioventricular nodal reentry tachycardia: observations by simultaneous multisite catheter mapping of Koch's triangle.

BACKGROUND: Selective ablation of either the fast of the slow pathway resulting in cure of AV nodal reentry tachycardia (AVNRT) has led to the concept that these pathways are discrete, anatomically defined structures. We hypothesized that if a discrete retrograde fast pathway exists, it should be possible to record a single focus of early atrial activation near the apex of Koch's triangle, with sequential spread of depolarization to the rest of the atria. METHODS AND RESULTS: We evaluated 46 patients (33 women, 13 men; mean age, 45 +/- 17 years) undergoing electrophysiology study and catheter ablation for typical AVNRT. Retrograde atrial activation during AVNRT (337 +/- 43 ms) and ventricular pacing at a similar cycle length (352 +/- 51 ms) was recorded in the region of Koch's triangle with a decapolar catheter in the His bundle position, a multipolar catheter in the coronary sinus, and a deflectable quadripolar catheter along the tricuspid annulus anterior to the coronary sinus ostium. Earliest atrial activation was recorded at the apex of the triangle of Koch in 38 patients during ventricular pacing and in 43 patients during AVNRT. A broad wave front of atrial activation was recorded in 17 patients during ventricular pacing and in 26 patients during AVNRT. During AVNRT, only 2 patients had a single early site with focal and sequential activation along the tendon of Todaro. There was concordance in the pattern of atrial activation between ventricular pacing and AVNRT in only 21 of 46 patients. CONCLUSIONS: Retrograde atrial activation over the fast pathway is heterogeneous within Koch's triangle and the coronary sinus, both for the entire population and for individual patients during different modes of activation. These data do not support the concept of an anatomically discrete retrograde fast pathway.

Adult↗