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Biomedical subjects

Amgad N Makaryus

Publications and source records attributed to Amgad N Makaryus.

At least 19 recordsLinked to original sources
PubMed2006

Clinical investigation: Utility of left ventricular end diastolic diameter in the prediction of susceptibility to ventricular tachyarrhythmias.

BACKGROUND: Prior studies have shown the utility of using both QRS duration and QT dispersion (QTd) as predictors of risk for ventricular tachyarrhythmias (VA). Lengthening of the QRS duration represents dyssynchrony of regional myocardial wall contraction, and increased QTd similarly represents variations in myocardial repolarization. We sought to examine the left ventricular end diastolic diameter (LVEDD) as a predictor of VA susceptibility. METHODS: Eighty-eight patients referred for electrophysiologic (EP) studies were evaluated. EP testing was performed using a standard protocol of up to three extrastimuli. QTd and QRS duration analyses were performed in a blinded manner. Values were defined as abnormal if QRS duration>120 ms, QTd>60 ms, and LVEDD>6 cm. RESULTS: Of 88 patients (65 males; 23 females; mean age 67+/-15 years), 33 were inducible by EP testing. Patients with either increased QRS duration or QTd are shown to be at greater risk for VA inducibility. LVEDD is a strong predictor of inducibility for VA (p<0.02 between inducible and non-inducible patients). LVEDD in combination with QRS duration and QTd, further strengthens predictability for VA (p<0.03 for QRS duration and p<0.02 for QTd) with a trend towards inducibility as each value increases. Combination of the three parameters of QRS duration, QTd, and LVEDD was 91% sensitive for the identification of those patients inducible for VA. CONCLUSION: The LVEDD is an echocardiographic value that strongly predicts VA inducibility, and when combined with QRS duration and QTd, identifies patients at higher risk for these tachyarrhythmias.

Aged↗
PubMed2006

An unusual combination of myocardial bridging and coronary artery aneurysm identified on 64-detector coronary angiography.

Coronary artery aneurysm is an uncommon finding. It is defined as a dilated coronary artery which exceeds the diameter of the normal adjacent vessel by 1.5-2 times. Although theorized mechanisms include atherosclerotic coronary artery disease (CAD) and iatrogenic causes such as the use of percutaneous coronary interventions (PCI), the natural history and prognosis of this disease remain obscure. We describe a case of a 75 year old man who was found to have a long segmental myocardial bridge immediately followed by a 5 mm inner diameter aneurysm in the left anterior descending artery (LAD) detected on 64-detector cardiac computed tomography (64-CT). The post myocardial bridge aneurysmal dilatation in this case is unique, and has not been previously described. With the advent of 64-CT, more incidental cardiac anomalies and irregularities are likely to be found. In the end, the question as to the clinical significance of these findings and their treatment remains controversial. We report this novel case and review the literature for recommendations on treatment and management of patients with coronary aneurysms.

Aged↗
PubMed2006

Coronary artery stent fracture.

Coronary stent fracture is a rare but potentially serious complication of coronary artery stenting. In light of the non-specific presentation of stent fracture, it is also an easily missed complication. In order to ensure rapid recognition and treatment of this entity, physicians must be aware of its existence and its possibility under the right circumstances. We present the case of a 61-year-old Guyanese male who presented with unstable angina secondary to a stent fracture within two weeks of elective percutaneous coronary intervention (PCI) for in-stent restenosis.

Angina, Unstable↗
PubMed2006

Dynamic left ventricular outflow tract obstruction induced by dobutamine stress echocardiography leading to myocardial ischemia and infarction.

Left ventricular outflow tract (LVOT) obstruction occurring during dobutamine stress echocardiography (DSE) occurs in approximately 15-20% of patients undergoing DSE. The clinical significance and mechanism of LVOT obstruction has been debated, but is now generally felt to result from the pharmacological effects of dobutamine in increasing inotropy and causing peripheral vasodilation. It must be realized that in rare instances, ischemia may occur and lead to wall motion abnormalities and eventually myocardial infarction. We present the case of a 70-year-old asymptomatic woman who underwent a routine pre-operative cardiac stress evaluation and was found to develop a dynamic outflow tract obstruction leading to myocardial ischemia and infarction.

Aged↗
PubMed2006

"Sensing alternans" in a patient with a newly implanted pacemaker.

This report describes the case of an 80-year-old man with a history of coronary artery disease who presented with acute pericarditis secondary to pacemaker lead perforation of the ventricular wall 2 days after undergoing dual lead pacemaker implantation. The electrocardiogram revealed sinus rhythm with an intra-atrial conduction delay and intermittent failure of atrial sensing as evidenced by alternating atrial spikes in every other P wave. The noted pericardial effusion and the likely shifting of the atrial lead with each alternate beat caused the "sensing alternans" that was seen on the admission electrocardiogram.

Aged↗
PubMed2006

Effect of ciprofloxacin and levofloxacin on the QT interval: is this a significant "clinical" event?

BACKGROUND: The widespread use of the fluoroquinolones has raised the question of the cardiac safety of these medications. This widespread use of this class of antibiotics has displayed their safety profile, which is actually more favorable than many other drug classes. The cardiac toxicity issue at the center of this discussion is the prolongation of the QT interval leading to torsade de pointes. Ciprofloxacin and levofloxacin, two of the more commonly used fluoroquinolones, are considered less likely than other fluoroquinolones to prolong the QT interval. The authors set out to evaluate the effect on the QT interval of patients after administration of ciprofloxacin and levofloxacin. METHODS: A prospective evaluation of 38 consecutive patients evaluated by the infectious disease service and receiving either ciprofloxacin or levofloxacin was undertaken. Twelve-lead electrocardiograms were obtained at baseline and at least 48 hours after the first dose of the antibiotic was administered. Both the longest QT interval and the mean QT interval were evaluated. To account for variations in heart rate, the corrected QT interval was calculated by using Bazett's formula (QTc = QT(square root of) R-R). Statistical analysis was undertaken to assess for the presence of a change after the administration of the antibiotic. RESULTS: Thirty-eight patients (mean age, 65 +/- 19 years), 23 women and 15 men, were studied. There was a small but significant increase in the longest QTc intervals over baseline in patients receiving levofloxacin; there was no significant change in the mean QTc interval. However, one patient who received levofloxacin was, statistically, an outlier and, on retrospective analysis, had demonstrated severe electrolyte disturbances at the time of the study. When this patient was excluded, the increase in the longest QTc interval was not significant. Patients receiving ciprofloxacin did not demonstrate any significant change in the longest QTc interval or mean QTc interval. CONCLUSIONS: Neither levofloxacin nor ciprofloxacin significantly prolonged the mean QTc interval over baseline. When electrolyte deficiencies in one of the patients evaluated were taken into account, this also held true for the longest QTc interval. There is, therefore, evidence that taking ciprofloxacin or levofloxacin, assuming that there are not any concurrent risk factors, will not cause a significant prolongation in the QT interval.

Aged↗
PubMed2006

Acute myocardial infarction following the use of intranasal anesthetic cocaine.

The use of cocaine has become largely obsolete in modern medical practice; however, it is still used by otolaryngologists for topical anesthesia in head and neck surgeries. We present the case of a 68-year-old woman who developed a myocardial infarction after the use of topical cocaine during nasal sinus surgery, and review the literature regarding the use of cocaine as a topical anesthetic in otolaryngologic practice. Awareness is raised of a possible complication of myocardial infarction following topical cocaine anesthetic use.

Administration, Intranasal↗
PubMed2006

Emotion-triggered cardiac asystole-inducing neurocardiogenic syncope.

The pathophysiology of neurocardiogenic syncope (NCS) is multifactorial. Recurrent syncopal episodes can result in injury and can provoke substantial anxiety among patients. Although an abundance of descriptions of various forms of syncope have been reported in the literature, few articles to date address a documented case due to emotional stress or sound. This is a report of a 31-year-old woman who fainted after being startled by someone sneezing. Review of the episode on her event recorder revealed a transient cardiac asystole of 10 seconds. We discuss the incidence of NCS and the proposed mechanism by which this syncopal event occurred.

Adult↗
PubMed2006

Efficacy of rheolytic thrombectomy in early versus late myocardial infarction.

BACKGROUND: Rheolytic thrombectomy has been used successfully to treat acutely occluded lower-limb vessels, dialysis grafts, intrahepatic portosystemic shunts, and diseased native coronary vessels and saphenous vein grafts. Few studies, however, have examined the efficacy of rheolytic thrombectomy in the acute myocardial infarction (AMI) setting. We sought to determine the efficacy of the AngioJet Rheolytic thrombectomy catheter (Possis Medical, Minneapolis, MN, USA) in patients presenting with AMI either before or after 12 hours of onset of symptoms. METHODS: Procedural and angiographic data on 61 consecutive patients (January 2003-December 2003) who presented with an AMI and had rheolytic thrombectomy with the AngioJet catheter performed were reviewed. Coronary flow was assessed with thrombolysis in myocardial infarction (TIMI) frame counts (TFCs). Of the 61 patients studied, 40 had AngioJet performed within 12 hours and 21 had it done after 12 hours from the onset of symptoms. Procedural success was measured by TFCs measured before and after the procedure and was defined as a change in the TFC of >or=50%. Statistical significance was considered at a P value of <0.05. RESULTS: Procedural success was achieved in 75% of the patients in the early presentation group (within 12 hours) and 0% of the patients in the late presentation group (after 12 hours). TFC values were statistically different (P<0.001) in the early group, but not significant (P>0.1) in the late thrombectomy group. CONCLUSION: Rheolytic thrombectomy with the AngioJet catheter is more effective in terms of improvement in coronary blood flow as assessed by TFCs when used less than 12 hours after the onset of clinical symptoms suggestive of AMI.

Cardiac Catheterization↗
PubMed2006

Diabetes insipidus: diagnosis and treatment of a complex disease.

Diabetes insipidus, characterized by excretion of copious volumes of dilute urine, can be life-threatening if not properly diagnosed and managed. It can be caused by two fundamentally different defects: inadequate or impaired secretion of antidiuretic hormone (ADH) from the posterior pituitary gland (neurogenic or central diabetes insipidus) or impaired or insufficient renal response to ADH (nephrogenic diabetes insipidus). The distinction is essential for effective treatment.

Diabetes Insipidus↗
PubMed2006

Ventricular arrhythmias in dialysis patients.

The occurrence of ventricular arrhythmias is common in renal failure patients who are receiving long-term hemodialysis. Associated ventricular arrhythmias may account for a major component of the cardiovascular mortality in hemodialysis patients. In the literature, a number of factors have been implicated in the genesis of these arrhythmias. Postulated theories range from hemodynamic alterations induced by dialysis, to metabolic alterations and derangements, to the molecular level of the current alterations in the L-type calcium channels of the heart. Studies have been conducted to ascertain whether testing, with signal-averaged electrocardiograms or electrophysiologic studies, can help to predict whether certain patients with renal failure might be more at risk for developing the complex arrhythmias noted in a large proportion of renal failure patients undergoing dialysis. This article examines the literature with regard to possible predictors in terms of patient characteristics, risk factors, electrophysiologic variables, and even dialysis method, all of which may play a part in determining the likelihood of a patient developing a ventricular arrhythmia.

Arrhythmias, Cardiac↗
PubMed2006

Ruptured sinus of valsalva aneurysm in a pregnant woman.

A ruptured sinus of Valsalva aneurysm is a rare cardiac anomaly, usually of a congenital nature. There are few documented cases of this condition during pregnancy, which renders unclear the therapeutic options. We report the case of a 35-year-old pregnant woman who presented at the hospital for cardiac evaluation due to the presence of a heart murmur. The patient was asymptomatic and in her 4th month of pregnancy. Transthoracic echocardiography revealed a ruptured sinus of Valsalva aneurysm and a fistula to the right ventricle with evidence of a continuous left-to-right shunt.

Adult↗
PubMed2006

Aspirin resistance, an emerging, often overlooked, factor in the management of patients with coronary artery disease.

Aspirin is the most widely used medication in patients with cardiovascular disease. It has had a greater effect on patients with cardiovascular disease than any other drug. With the importance of aspirin now known for decades, it is recently becoming clearer that some patients do not derive as great a benefit from this "wonder drug" secondary to their resistance to its effects. Aspirin resistance, its prevalence, its identification, and how to overcome or avert it with other medications then becomes a central topic of discussion as important, if not more so, than the importance of aspirin itself as a cornerstone in the treatment of patients with cardiovascular disease. This review explores the current understanding of the mechanism of aspirin resistance with regard to its prevalence and the magnitude of its clinical significance. It also examines the therapeutic implications of a diagnosis of aspirin resistance.

Aspirin↗
PubMed2006

Pregnancy in the patient with Eisenmenger's syndrome.

Eisenmenger's syndrome occurs when a large congenital or surgically created shunt between the left and right sides of the heart causes an increase in pulmonary vascular resistance that equals or surpasses systemic resistance, resulting in a reversal of the shunt from a left-to-right shunt to a right-to-left or bi-directional shunt. The maternal mortality rate of pregnancy in the presence of Eisenmenger's syndrome is reported to be as high as 50-65% with cesarean section. We present the case of a 32-year-old woman with Eisenmenger's syndrome who gave birth at 29 weeks of gestation via C-section to a healthy baby boy, and we review the literature regarding the management of such patients.

Adult↗