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Biomedical subjects

R Goyal

Publications and source records attributed to R Goyal.

At least 37 records · Page 2Linked to original sources
PubMed1999

Short-term effect of atrial fibrillation on atrial contractile function in humans.

BACKGROUND: Conversion of chronic atrial fibrillation (AF) is associated with atrial stunning, but the short-term effect of a brief episode of AF on left atrial appendage (LAA) emptying velocity is unknown. The purpose of this study was to determine whether a short episode of AF affects left atrial function and whether verapamil modifies this effect. METHODS AND RESULTS: The subjects of this study were 19 patients without structural heart disease undergoing an electrophysiology procedure. In 13 patients, LAA emptying velocity was measured by transesophageal echocardiography in the setting of pharmacological autonomic blockade before, during, and after a short episode of AF. During sinus rhythm, the baseline LAA emptying velocity was measured 5 times and averaged. AF was then induced by rapid right atrial pacing. After either spontaneous or electrical conversion, LAA emptying velocity was measured immediately on resumption of sinus rhythm and every minute thereafter. The mean duration of AF was 15.3+/-3.8 minutes. The mean baseline emptying velocity was 70+/-20 cm/s. The first post-AF emptying velocity was 63+/-20 cm/s (P=0.02 versus baseline emptying velocity). The post-AF emptying velocity returned to the baseline emptying velocity value after 3.0 minutes. The mean percent reduction in post-AF emptying velocity was 9.7+/-21% (range, 15% increase to 56% decrease). A second group of 6 patients were pretreated with verapamil (0.1-mg/kg IV bolus followed by an infusion of 0.005 mg. kg-1. min-1). In these patients, the first post-AF emptying velocity, 58+/-14 cm/s, was not significantly different from the pre-AF emptying velocity, 60+/-13 cm/s (P=0.08). CONCLUSIONS: In humans, several minutes of AF may be sufficient to induce atrial contractile dysfunction after cardioversion. When atrial contractile dysfunction occurs, there is recovery of AF within several minutes. AF-induced contractile dysfunction is attenuated by verapamil and may be at least partially mediated by cellular calcium overload.

Adult↗
PubMed1999

Proliferative characteristics of intestinalized mucosa in the distal esophagus and gastroesophageal junction (short-segment Barrett's esophagus): a case control study.

Intestinalized epithelium in traditional long-segment Barrett's esophagus (BE) shows increased proliferative activity, which is postulated to be an early step in the metaplasia-dysplasia-carcinoma sequence. The aim of this study was to evaluate the proliferative activity of intestinalized epithelium of the distal esophagus and gastroesophageal junction (IMEGEJ). Tissue sections from 78 consecutive patients (20 with IMEGEJ, 58 without IMEGEJ) who had elective upper gastrointestinal endoscopy over a 6-month period were immunohistochemically stained with MIB-1, the Ki-67 proliferation-antigen-associated marker, for evaluation of the crypt MIB-1 proliferation index (PI), size of the proliferative zone (PZ), and the presence of surface epithelial staining. Data from the IMEGEJ and non-IMEGEJ groups, and from 15 age-matched patients with traditional long-segment BE (>3.0 cm), were compared statistically. IMEGEJ patients showed a statistically significant increase in the mean crypt PI compared with non-IMEGEJ controls (21.9+/-19.5 v 14.3+/-9.3; P=.01). In addition, IMEGEJ cases showed an increase in the mean crypt PZ (52.3+/-16.4 v 45.2+/-17.2; P=.05), and a trend toward an increase in the percentage of cases with MIB-1-positive surface epithelial cells (50% v 33%, P=.18). Patients with IMEGEJ did not differ from patients without IMEGEJ with respect to any other clinical or histological feature, including signs or symptoms of gastroesophageal reflux disease and presence or absence of esophagitis or carditis. The MIB-1 results of the patients with long-segment BE (MIB-1 PI = 22.6+/-20.5, MIB-1 PZ = 51.8+/-19.6, proportion of cases with MIB-1-positive surface cells = 66%) were similar to those with IMEGEJ. Intestinalized epithelium in the distal esophagus or gastroesophageal junction shows increased proliferative activity in comparison with patients without intestinalized epithelium. This finding supports an increased risk of carcinogenesis in patients with IMEGEJ.

Adult↗
PubMed1999

Significance of acid-mucin-positive nongoblet columnar cells in the distal esophagus and gastroesophageal junction.

Acidic mucin-positive nongoblet columnar cells (NGCC) have recently been observed in the surface epithelium of the gastroesophageal junction (GEJ) and distal esophagus in resections from patients with traditional long segment (>3 cm) Barrett's esophagus (BE). However, the significance of finding acidic mucin-positive NGCC in the surface epithelium of biopsy specimens from the distal esophagus/GEJ region in the absence of goblet cells (GC) remains unknown. Therefore, to determine the significance of mucin histochemical changes in the distal esophagus/GEJ region, we analyzed and compared the types, prevalence, and distribution of neutral and acidic mucins in biopsy specimens obtained from 2 groups of patients: those with (32 patients) and those without (107 patients) GC identified in this area. Various mucin histochemical stains (PAS-Ab pH 2.5, HID-Ab pH 2.5, PB/KOH/PAS) were used to identify neutral mucins, acidic mucins (sialomucins and sulphomucins), and o-acetylated sialomucins. The results were compared between the 2 patient groups and correlated with the clinical, endoscopic, and pathologic features. Compared with patients without GC, patients with GC had a significantly higher male/female ratio and a higher proportion of patients with greater than 3 cm of columnar epithelium within the esophagus. Acidic mucin (sialomucin and sulphomucin)-positive NGCC in the surface, foveolar, and glandular epithelium did not show any correlation with any of the clinical, endoscopic, or pathologic features, such as esophagitis, carditis, antritis, Helicobacter pylori infection, or length of columnar epithelium in the distal esophagus. However, acidic mucin-positive NGCC correlated strongly with the presence of GC (P < .001). For example, sialomucin-positive NGCC were present in 28 of 32 (88%) patients with GC compared with 31 of 107 (29%) patients without GC (P < .001). Similarly, sulphomucin-positive NGCC were present in 20 of 32 (62%) patients with GC, compared with 11 of 107 (10%) patients without GC (P < .001). Of the non-GC cases, all biopsy specimens that stained positively for sulphomucin in surface NGCC (11 specimens), except one, showed staining restricted to the surface of multilayered epithelium, a distinctive type of epithelium that shows morphological, ultrastructural, and cytochemical features of both squamous and columnar epithelium. Sialomucin positivity in surface NGCC from the distal esophagus/GEJ region is a sensitive (sensitivity 88%), but nonspecific (specificity 71%), indicator of GC metaplasia. In contrast, sulphomucin expression in NGCC from the same anatomic area is a less sensitive (sensitivity 62%), but more specific (specificity = 90%) marker for the presence of metaplastic epithelium, of either the GC or the multilayered epithelial cell type and thus may represent an early or incomplete form of intestinal metaplasia.

Adolescent↗
PubMed1999

Sezary cells with hairy projections.

A case of sezary syndrome where the sezary cells showed cytoplasmic hairy projections is reported. The patient had typical exfoliative erythematous dermatitis, high white cell count, atypical lymphocytes of T-phenotype with folded nuclei and bone marrow involvement. The ultra structure study showed cerebriform nucleus and cytoplasmic projections.

Adult↗
PubMed1999

Biologic characteristics of patients with hypocellular myelodysplastic syndromes.

Rates of proliferation and apoptosis as well as expression of tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta) and the number of macrophages were measured in bone marrow (BM) biopsies of 33 patients who presented with hypocellular (cellularity < 30%) myelodysplastic syndromes (MDS). Results showed that 2/3 of the patients had high apoptosis, high cytokine levels and large number of macrophages in their biopsies while 1/3 did not. Apoptosis and TNF-alpha levels were directly related (r = 0.583, P = 0.003, n = 24) as was apoptosis and the degree of anemia (P = 0.033, n = 18). A subgroup of patients with abnormalities of chromosomes 5 or 7 had higher platelets (P = 0.026) and higher apoptosis (P = 0.038) when compared with the rest of the group. Eight patients had no evidence of apoptosis and almost no detectable TNF-alpha in their biopsies. We conclude that within the hypocellular variant of MDS, there may be two distinct sub-groups of patients, one who present with high cytokine-mediated intramedullary apoptosis and the other who may be better characterized as having a stem-cell failure defect since they showed no evidence of apoptosis.

Adolescent↗
PubMed1999

A technique for the rapid diagnosis of atrial tachycardia in the electrophysiology laboratory.

OBJECTIVE: The purpose of this study was to determine if the atrial response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction during paroxysmal supraventricular tachycardia is a useful diagnostic maneuver in the electrophysiology laboratory. BACKGROUND: Despite various maneuvers, it can be difficult to differentiate atrial tachycardia from other forms of paroxysmal supraventricular tachycardia. METHODS: The response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction was studied during four types of tachycardia: 1) atrioventricular nodal reentry (n = 102), 2) orthodromic reciprocating tachycardia (n = 43), 3) atrial tachycardia (n = 19) and 4) atrial tachycardia simulated by demand atrial pacing in patients with inducible atrioventricular nodal reentry or orthodromic reciprocating tachycardia (n = 32). The electrogram sequence upon cessation of ventricular pacing was, categorized as "atrial-ventricular" (A-V) or "atrial-atrial-ventricular" (A-A-V). RESULTS: The A-V response was observed in all cases of atrioventricular nodal reentrant and orthodromic reciprocating tachycardia. In contrast, the A-A-V response was observed in all cases of atrial tachycardia and simulated atrial tachycardia, even in the presence of dual atrioventricular nodal pathways or a concealed accessory atrioventricular pathway. CONCLUSIONS: In conclusion, an A-A-V response upon cessation of ventricular pacing associated with 1:1 ventriculoatrial conduction is highly sensitive and specific for the identification of atrial tachycardia in the electrophysiology laboratory.

Adolescent↗
PubMed1999

Outcome of patients with nonischemic dilated cardiomyopathy and unexplained syncope treated with an implantable defibrillator.

OBJECTIVES: The purpose of this study was to determine the outcome of patients with nonischemic dilated cardiomyopathy, unexplained syncope and a negative electrophysiology test who are treated with an implantable defibrillator. BACKGROUND: Patients with nonischemic cardiomyopathy and unexplained syncope may be at high risk for sudden cardiac death, and they are sometimes treated with an implantable defibrillator. METHODS: This study prospectively determined the outcome of 14 consecutive patients who had a nonischemic cardiomyopathy, unexplained syncope and a negative electrophysiology test and who underwent defibrillator implantation (Syncope Group). Nineteen consecutive patients with a nonischemic cardiomyopathy and a cardiac arrest who were treated with a defibrillator (Arrest Group) served as a control group. RESULTS: Seven of 14 patients (50%) in the Syncope Group received appropriate shocks for ventricular arrhythmias during a mean follow-up of 24+/-13 months, compared with 8 of 19 patients (42%) in the Arrest Group during a mean follow-up of 45+/-40 months (p = 0.1). The mean duration from device implantation until the first appropriate shock was 32+/-7 months (95% confidence interval [CI], 18 to 45 months) in the Syncope Group compared to 72+/-12 months (95% CI, 48 to 96 months) in the Arrest Group (p = 0.1). Among patients who received appropriate shocks, the mean time from defibrillator implantation to the first appropriate shock was 10+/-14 months in the Syncope Group, compared with 48+/-47 months in the Arrest Group (p = 0.06). Recurrent syncope was always associated with ventricular tachyarrhythmias. CONCLUSIONS: The high incidence of appropriate defibrillator shocks and the association of recurrent syncope with ventricular arrhythmias support the treatment of patients with nonischemic cardiomyopathy, unexplained syncope and a negative electrophysiology test with an implantable defibrillator.

Cardiomyopathy, Dilated↗
PubMed1999

Interaction between autonomic tone and the negative chronotropic effect of adenosine in humans.

Prior studies have demonstrated that sympathetic tone may influence the effects of adenosine on His-Purkinje automaticity, and that enhanced vagal tone may influence its effects on the sinus node. However, the interaction between autonomic tone and the effects of adenosine on the sinus node in humans remains unknown. Therefore, this study was designed to investigate the interaction between different states of autonomic tone and the bradycardiac response of the sinus node to adenosine. In 11 patients without structural heart disease who underwent a clinically indicated electrophysiology procedure, the sinus cycle length was measured before and after a 12-mg bolus of adenosine in the baseline state, during an infusion of 2 mcg/min of isoproterenol, after the administration of 0.2 mg/kg of propranolol, and again after the administration of 0.04 mg/kg of atropine. Adenosine significantly lengthened the sinus cycle length in the baseline state (760 +/- 165 vs 909 +/- 188 ms, P < 0.05), during isoproterenol infusion (516 +/- 67 vs 766 +/- 146 ms, P < 0.05), after propranolol (850 +/- 153 vs 914 +/- 143 ms, P < 0.05) and after the combination of propranolol and atropine (662 +/- 76 vs 801 +/- 121 ms, P < 0.05). The degree of lengthening in sinus cycle length was significantly greater (P < 0.05) during isoproterenol infusion (253 +/- 157 ms, or 51% +/- 40%) than in the baseline state (149 +/- 85 ms, or 20% +/- 12%), after propranolol (68 +/- 53 ms, or 8% +/- 8%), and after propranolol and atropine (140 +/- 110 ms, or 21% +/- 18%). The negative chronotropic effect of adenosine is influenced by autonomic tone. The effect of adenosine on the sinus node is accentuated by beta-adrenergic stimulation and unaffected by beta-adrenergic blockade or combined beta-adrenergic and cholinergic blockade.

Adenosine↗
PubMed1999

Target temperatures of 48 degrees C versus 60 degrees C during slow pathway ablation: a randomized comparison.

INTRODUCTION: The relationship between temperature at the electrode-tissue interface and the loss of AV and ventriculoatrial (VA) conduction is not established, and the optimal target temperature for the slow pathway approach to radiofrequency ablation of AV nodal reentrant tachycardia (AVNRT) is unknown. Therefore, the purpose of this study was to compare target temperatures of 48 degrees C and 60 degrees C during the slow pathway approach to ablation of AVNRT. METHODS AND RESULTS: The study included 138 patients undergoing ablation for AVNRT. Patients undergoing slow pathway ablation using closed-loop temperature monitoring were randomly assigned to a target temperature of either 48 degrees C or 60 degrees C. The primary success rates were 76% in the patients assigned to 48 degrees C and 100% in the patients assigned to 60 degrees C (P < 0.01). The ablation procedure duration (33 +/- 31 min vs 26 +/- 28 min; P = 0.2), fluoroscopic time (25 +/- 15 min vs 24 +/- 16 min; P = 0.5), and mean number of applications (9.3 +/- 6.5 vs 7.8 +/- 8.1; P = 0.3) were similar in patients assigned to 48 degrees and 60 degrees C, respectively. The mean temperature (46.1 degrees +/- 24.8 degrees C vs 48.7 +/- 3.2 degrees C; P < 0.01), the temperature associated with junctional ectopy (48.1 degrees +/- 2.0 degrees C vs 53.5 degrees +/- 3.5 degrees C, P < 0.0001), and the frequency of VA block during junctional ectopy (24.6% vs 37.2%; P < 0.0001) were less in the patients assigned to 48 degrees C compared to 60 degrees C. The frequency of transient or permanent AV block was similar in each group (2.8% vs 3.6%; P = 0.2). In the 60 degrees C group, only 12% of applications achieved an electrode temperature of 60 degrees C. During follow-up of 9.9 +/- 4.2 months, there was one recurrence of AVNRT in the 48 degrees C group and none in the 60 degrees C group. CONCLUSIONS: Compared to 48 degrees C, a target temperature of 60 degrees C during radiofrequency slow pathway ablation is associated with a higher primary success rate and a higher incidence of VA block during junctional ectopy induced by the radiofrequency energy. AV block is not more common with the higher target temperature, but only if VA conduction is aggressively monitored during applications of radiofrequency energy.

Adult↗
PubMed1999

Clinical value of the postpacing interval for mapping of ventricular tachycardia in patients with prior myocardial infarction.

INTRODUCTION: The postpacing interval (PPI) has been used to discriminate bystander sites from critical sites within a ventricular tachycardia (VT) reentry circuit, with a PPI that is similar to the VT cycle length (CL) being indicative of a site within the reentry circuit. The purpose of this study was to assess the clinical value of the PPI for identifying effective target sites for ablation of VT at sites of concealed entrainment in patients with prior myocardial infarction. METHODS AND RESULTS: In 24 patients with coronary artery disease and a past history of myocardial infarction, 36 VTs with a mean CL of 483+/-80 msec (+/- SD) were mapped and targeted for radiofrequency (RF) ablation. The only criterion used to select target sites for ablation was concealed entrainment. In a post hoc analysis, the PPI was measured at 47 ineffective and 26 effective ablation sites. The mean PPI-VTCL difference at the 26 effective sites (114+/-137 msec) did not differ significantly from the mean at the 47 ineffective sites (177+/-161 msec; P = 0.1). The sensitivity of a PPI-VTCL difference < or = 30 msec for identifying an effective ablation site was 46%, the specificity 64%, the positive predictive value 41%, and the negative predictive value 68%. CONCLUSION: The PPI-VTCL difference is not useful for discriminating between sites of concealed entrainment that are within or outside of a VT reentry circuit in patients with prior infarction. Therefore, in patients with prior infarction, the PPI is not clinically useful for identifying sites of concealed entrainment at which RF ablation should or should not be attempted.

Aged↗
PubMed1999

Discrete systolic potentials during ventricular tachycardia in patients with prior myocardial infarction.

INTRODUCTION: Isolated diastolic potentials have been found to be helpful in identifying critical sites for ablation of ventricular tachycardia (VT) in patients with coronary artery disease. However, discrete potentials that occur during systole have not been previously described. The purpose of this study was to determine the significance of discrete systolic potentials during VT in patients with coronary artery disease. METHODS AND RESULTS: Twenty-seven patients with a mean age of 66 +/- 12 years ( +/- standard deviation) who had coronary artery disease underwent radiofrequency catheter ablation of 42 VTs that had a mean cycle length of 486 +/- 78 msec. The only criterion used to select target sites for ablation was concealed entrainment, which was present at 92 sites. Thirty-five of the 42 VTs (83%) were successfully ablated. A discrete systolic potential was recorded during 7 of the 42 VTs (17%). In all cases, the interval between the discrete systolic potential and the next QRS complex was equal to the stimulus-QRS interval during concealed entrainment. At all seven sites where a discrete systolic potential was recorded, delivery of radiofrequency energy resulted in successful ablation of the VT. CONCLUSION: Discrete systolic potentials may be present in patients with coronary artery disease in approximately 17% of VTs in which there is concealed entrainment. If the interval between the discrete systolic potential and the next QRS complex matches the stimulus-QRS interval during concealed entrainment, delivery of radiofrequency energy is likely to result in successful ablation of the VT.

Action Potentials↗
PubMed1999

Relationship between shock energy and postdefibrillation ventricular arrhythmias in patients with implantable defibrillators.

BACKGROUND: The relationship between postdefibrillation ventricular arrhythmias and shock strength is poorly understood in patients with implantable defibrillators. The purpose of this study was to characterize the relationship between postdefibrillation ventricular arrhythmias and shock strength. METHODS AND RESULTS: Forty-three patients with an implanted defibrillator underwent six separate inductions of ventricular fibrillation (VF) after a step-down defibrillation energy requirement (7.3 +/- 4.6 J) was determined. For each of the first three inductions of VF, the first two shocks were low energy and equal to approximately 75% of the defibrillation energy requirement (5.4 +/- 3.3 J), or to the defibrillation energy requirement plus 10 J (17.5 +/- 4.3 J). After the first two shocks, subsequent shocks were programmed to the maximum available energy (29.0 +/- 2.5 J). The alternate technique was used for the subsequent three inductions of VF. Postdefibrillation ventricular arrhythmias were noted. Postdefibrillation ventricular arrhythmias with a cycle length < or = 300 msec were more frequent after a low-energy shock (19%), than after a high-energy shock (1.5%; P = 0.005). Postdefibrillation ventricular arrhythmias with a cycle length < or = 300 msec were more frequent after a high-energy shock (32%), than after a low-energy shock (7.1%; P = 0.002). A relationship between the cycle length of the postdefibrillation ventricular arrhythmias and the absolute defibrillation energy was observed (P < 0.001; r = 0.6), and ventricular arrhythmias with a cycle length > 300 msec were uncommon after shocks < or = 10 J (P = 0.001). The characteristics of ventricular arrhythmias after maximum-energy shocks were similar to those that occurred after high-energy shocks. CONCLUSIONS: Postdefibrillation ventricular arrhythmias with a cycle length < or = 300 msec are more common after shocks of strength associated with a low probability of successful defibrillation. Postdefibrillation ventricular arrhythmias with a cycle length of > 300 msec are more common after high- and maximum-energy shocks, and are directly related to the absolute defibrillation energy.

Cardiomyopathies↗
PubMed1998

Acute changes in spontaneous echo contrast and atrial function after cardioversion of persistent atrial flutter.

With use of transesophageal echocardiography, the short-term effects of transthoracic electrical cardioversion of atrial flutter (AFI) on atrial mechanical function and spontaneous echo contrast were determined. Thirty patients who had AFI for a mean of 6.4 +/- 12.2 months underwent transthoracic cardioversion. A transesophageal echocardiogram was recorded immediately before cardioversion, and left atrial appendage emptying velocity and spontaneous contrast were assessed serially at 1, 3, and 5 minutes after cardioversion in 28 patients, and also at 8, 10, and 15 minutes after cardioversion in a subgroup of 13 patients. Cardioversion was deferred in 2 patients (7%) because a thrombus was found in the left atrial appendage. Before cardioversion, spontaneous contrast was present in the left atrium in 7 of 28 patients (25%) who underwent cardioversion. The mean left atrial appendage emptying velocity of 54 +/- 22 cm/s before cardioversion fell by 26% to 40 +/- 25 cm/s at 1 minute after restoration of sinus rhythm (p <0.01). There were no significant changes in the mean left atrial appendage-emptying velocity between 1 and 15 minutes after cardioversion. Within 5 minutes after conversion to sinus rhythm, left atrial spontaneous echo contrast developed de novo or worsened in 12 of the 28 patients (43%). In conclusion, the results of this study demonstrate that persistent AFI may be associated with left atrial thrombi before cardioversion and that cardioversion of AFI is associated with a significant degree of atrial stunning and formation of spontaneous echo contrast.

Adult↗
PubMed1998

Cardiac electrophysiologic effects of norepinephrine in human beings.

BACKGROUND: The electrophysiologic effects of norepinephrine (NE) in human beings have not been previously described. METHODS: The electrophysiologic effects of NE infused at a rate of 25 ng/kg/min were determined in 21 patients with a mean age of 41 +/- 11 years and without structural heart disease who underwent an electrophysiology procedure. In a subgroup of 10 patients electrophysiologic parameters were measured at baseline, after the infusion of NE, and after administration of beta-blockade while in continuous NE infusion. RESULTS: The baseline NE plasma concentration of 298 +/- 153 pg/ml increased to 708 +/- 419 pg/ml after the infusion of NE. NE significantly increased the mean blood pressure, sinus cycle length, corrected sinus node recovery time, ventriculoatrial block cycle length, and the atrial and ventricular effective refractory periods. In a subset of 10 patients 0.2 mg/kg propranolol administered during continued infusion of NE resulted in a further increase in sinus cycle length, atrial-His interval, and ventricular refractoriness. CONCLUSION: A physiologic elevation in the plasma NE concentration results in a depression of sinus node function and atrioventricular conduction and in prolongation of atrial and ventricular refractoriness. Some of NE's effects are partially offset by beta-adrenergic stimulation.

Adrenergic alpha-Agonists↗
PubMed1998

Use of adenosine in patients hospitalized in a university medical center.

PURPOSE: Adenosine is a useful agent for the diagnosis and termination of tachycardias. The purpose of this study was to identify the rhythms for which adenosine is prescribed in hospitalized adults and to identify the reasons for its misuse. PATIENTS AND METHODS: Data were collected from the medical records of 100 patients who received intravenous adenosine while hospitalized at a university medical center. The characteristics of the patients, rhythms treated with adenosine, and dosages of adenosine were analyzed. In addition, internal medicine house officers were administered a questionnaire referring to an electrocardiogram of atrial fibrillation with a rapid ventricular response. RESULTS: The arrhythmias for which adenosine was administered consisted of regular, narrow-QRS complex tachycardias in 33% of patients; atrial fibrillation in 32% of patients; regular, wide-QRS complex tachycardias in 23% of patients; atrial flutter in 10% of patients, and multifocal atrial tachycardia in 2% of patients. The mean (+/-SD) number of doses of adenosine given to each patient was 1.6+/-0.8, and the mean dose of adenosine was 7.8+/-2.8 mg. Internal medicine house officers prescribed 70% of the doses of adenosine and were as likely to use it for patients with atrial fibrillation as were surgical house officers. There was a 2% incidence of proarrhythmia, including asystole and polymorphic ventricular tachycardia. Thirty-one percent of the 100 house officers in our survey misdiagnosed a 12-lead electrocardiogram of rapid atrial fibrillation as paroxysmal supraventricular tachycardia, suggesting that adenosine may have been misused for atrial fibrillation because of errors in rhythm diagnosis. Only 5% of those who correctly diagnosed atrial fibrillation also answered that adenosine would be likely to terminate the arrhythmia, suggesting that a misunderstanding that adenosine terminates atrial fibrillation is not a common reason for its misuse. CONCLUSIONS: Approximately 40% of hospitalized adults who are treated with adenosine receive the medication unnecessarily for atrial fibrillation or atrial flutter, and this misuse results in unnecessary expenses and risks of adverse effects. The primary reason that adenosine is misused for atrial fibrillation is the inability to recognize that rhythm on an electrocardiogram. House officers need additional education on the electrocardiographic recognition of atrial fibrillation.

Adenosine↗