Inadequacy of Pulse Oximetry in the Catheterization Laboratory. An Exploratory Study Monitoring Respiratory Status Using Arterial Blood Gases during Cardiac Catheterization with Conscious Sedation.

BACKGROUND: Benzodiazepines and opioids are commonly used for conscious sedation (CS) in cardiac catheterization laboratory (CCL) patients. Both drugs are known to predispose to hypoxemia, apnea and decreased responsiveness to PCO2, resulting in decreased arterial pH and PO2, as well as increased PCO2. We want to determine the effects of CS on arterial blood gas (ABG) in CCL patient, and identify if pulse oximetry monitoring is adequate. METHODS: We enrolled 18 subjects undergoing elective catheterization. Measurement of ABGs at one-minute intervals was done from the moment of arterial access until case end. The results of ABGs were not available to the clinician who administered sedation. Relationships of pH, PCO2, PaO2 and SaO2 were studied by plotting time series graphs. Significant changes were defined as pH <7.30, SaO2 < 90, and PCO2 > 50 mmHg. RESULTS: No significant change in pH, PCO2, PaO2 and SaO2 was noted in 4/18 (22%) subjects. A significant drop in SaO2 was noted in 4/18 (22%). A significant change in PCO2 and/or pH was noted in 10/18 (55%) cases. Among the 16 (16/18) subjects receiving supplemental oxygen, 7 (7/18, 39%) had no drop in SaO2, but developed respiratory acidosis. At the end of the case, 5/18 (28%) subjects had respiratory acidosis with normal PaO2. CONCLUSION: Significant hypercarbia and acidosis occurred frequently in this small study during CS in patients undergoing cardiac catheterization. Relying on pulse oximetry alone especially with patients on supplemental oxygen may lead to failure in detecting respiratory acidosis in a significant number of patients.

Cardiac tumors in a tertiary care cancer hospital: clinical features, echocardiographic findings, treatment and outcomes.

Cardiac tumors are a rare entity, comprised of tumors with diverse histology and natural history. We report the clinical characteristics, echocardiograhic findings, therapy and outcome of 59 patients with primary and metastatic cardiac tumors. Our institutional echocardiogram data base from 1993 through 2005 was reviewed to identify patients diagnosed with intra-cardiac tumor. A total of 59 patients with cardiac tumors were identified and included in the study. The patients' characteristics, presenting symptoms, diagnostic tests, location, histology of the tumor, treatment and the one year survival rate of this population was collected from the medical records. Of the 59 cardiac tumor cases, 16 (27%) were primary cardiac tumors and 43 (73%) were secondary cardiac tumors. The most common primary tumor was sarcoma affecting 13 (81%) of the 16 cases. Of these, 5 patients were angiosarcoma, 5 unclassified sarcoma, one myxoid sarcoma and 2 malignant fibrous histiocytoma. The mean age at presentation was 41.1 years, and the most common location was right atrium affecting 6 cases (37.5%). The most common symptom of dyspnea was present in 10 (62.5%) cases. Eleven (25.6%) of the 43 secondary cardiac tumors were metastasis from renal cell carcinoma. The mean age at presentation was 55.4 years. Right atrium was the most frequent location affecting 18 (42%) of the 43 patients. The most common presenting symptom was dyspnea in 15 (35%) cases. For both primary and secondary tumors, dyspnea was the most common symptom and right atrium was most frequently involved. Sarcoma was the most common primary cardiac tumor while metastasis from renal cell carcinoma was the most common secondary tumor.

Apical hypertrophic cardiomyopathy.

We describe a patient with asymptomatic apical hypertrophic cardiomyopathy (AHCM) who later developed cardiac arrhythmias, and briefly discuss the diagnostic modalities, differential diagnosis and treatment option for this condition. AHCM is a rare form of hypertrophic cardiomyopathy which classically involves the apex of the left ventricle. AHCM can be an incidental finding, or patients may present with chest pain, palpitations, dyspnea, syncope, atrial fibrillation, myocardial infarction, embolic events, ventricular fibrillation and congestive heart failure. AHCM is frequently sporadic, but autosomal dominant inheritance has been reported in few families. The most frequent and classic electrocardiogram findings are giant negative T-waves in the precordial leads which are found in the majority of the patients followed by left ventricular (LV) hypertrophy. A transthoracic echocardiogram is the initial diagnostic tool in the evaluation of AHCM and shows hypertrophy of the LV apex. AHCM may mimic other conditions such as LV apical cardiac tumors, LV apical thrombus, isolated ventricular non-compaction, endomyocardial fibrosis and coronary artery disease. Other modalities, including left ventriculography, multislice spiral computed tomography, and cardiac magnetic resonance imagings are also valuable tools and are frequently used to differentiate AHCH from other conditions. Medications used to treat symptomatic patients with AHCM include verapamil, beta-blockers and antiarrhythmic agents such as amiodarone and procainamide. An implantable cardioverter defibrillator is recommended for high risk patients.

Myocardial Infarction due to Endocarditis.

We present a case of a 43-year-old man who sustained a myocardial infarction due to infective endocarditis.

Antiplatelet therapy and percutaneous coronary intervention in patients with acute coronary syndrome and thrombocytopenia.

Platelets are crucial in the pathogenesis of acute coronary syndrome. Treatment for acute coronary syndrome usually involves antiplatelet, anticoagulant, and antithrombotic therapy, and the performance of percutaneous coronary intervention. All of the medications are associated with bleeding sequelae and are typically withheld from patients who have thrombocytopenia. The safety of antiplatelet therapy and percutaneous coronary intervention in patients who have acute coronary syndrome and thrombocytopenia is unknown, and there are no guidelines or randomized studies to suggest a treatment approach in such patients. Acute coronary syndrome is uncommon in patients who have thrombocytopenia; however, it occurs in up to 39% of patients who have both thrombocytopenia and cancer. Herein, we present the cases of 5 patients with acute coronary syndrome, thrombocytopenia, and cancer who underwent percutaneous coronary intervention with stenting. Before intervention, their platelet counts ranged from 17 to 72 x 10(9)/L. One patient underwent preprocedural platelet transfusion. All were given aspirin, alone or with clopidogrel. One patient experienced melena (of colonic origin). No other patient experienced bleeding sequelae. Aside from the occasional use of antiplatelet and thrombolytic agents in patients with thrombocytopenia, no therapeutic recommendation can be made until data are available on a larger patient population. Until then, treatment should conform to specific clinical circumstances. Approaches to the treatment of acute coronary syndrome in patients with thrombocytopenia might be better directed toward the evaluation of platelet function rather than toward absolute platelet count, and the risk-benefit equation of invasive procedures and antithrombotic therapies may need to incorporate this information.

Acute myocardial infarction associated with nonbacterial thrombotic endocarditis.

Herein, we describe the cases of 4 patients who each experienced a myocardial infarction in association with nonbacterial thrombotic endocarditis. We discuss the clinical presentation of this rare condition, distinguish between infective and nonbacterial thrombotic endocarditis via a review of the medical literature, and present treatment options for myocardial infarction that is associated with nonbacterial thrombotic endocarditis.

5-Fluorouracil-induced coronary vasospasm.

Cardiotoxicity due to 5-fluorouracil involves rare and life-threatening cardiotoxic events occurring in less than 1% of the patients. We describe a case of coronary vasospasm due to parenteral 5-fluorouracil, which did not recur with oral capecitabine. We also give a brief review of the cardiotoxicity of 5-fluorouracil, its treatment and prevention.