Heart sounds: Past, present, and future from a technological and clinical perspective - a systematic review.

The high prevalence of cardiac diseases around the world has created a need for quick, easy and cost effective approaches to diagnose heart disease. The auscultation and interpretation of heart sounds using the stethoscope is relatively inexpensive, requires minimal to advanced training, and is widely available and easily carried by healthcare providers working in urban environments or medically underserved rural areas. Since René-Théophile-Hyacinthe Laennec's simple, monoaural design, the capabilities of modern-day, commercially available stethoscopes and stethoscope systems have radically advanced with the integration of electronic hardware and software tools, however these systems are largely confined to the metropolitan medical centers. The purpose of this paper is to review the history of stethoscopes, compare commercially available stethoscope products and analytical software, and discuss future directions. Our review includes a description of heart sounds and how modern software enables the measurement and analysis of time intervals, teaching auscultation, remote cardiac examination (telemedicine) and, more recently, spectrographic evaluation and electronic storage. The basic methodologies behind modern software algorithms and techniques for heart sound preprocessing, segmentation and classification are described to provide awareness.

Gender Differences in the Pursuit of Cardiac Electrophysiology Training in North America.

BACKGROUND: Despite the increase in the number of female physicians across most specialties within cardiology, <10% of clinical cardiac electrophysiology (EP) fellows are women. OBJECTIVES: This study sought to determine the factors that influence fellows-in-training (FITs) to pursue EP as a career choice and whether this differs by gender. METHODS: The authors conducted an online multiple-choice survey through the American College of Cardiology to assess the decision factors that influence FITs in the United States and Canada to pursue cardiovascular subspecialties. RESULTS: A total of 933 (30.5%) FITs completed the survey; 129 anticipated specializing in EP, 259 in interventional cardiology (IC), and 545 in a different field or were unsure. A total of 1 in 7 (14%) FITs indicated an interest in EP. Of this group, more men chose EP than women (84% vs 16%; P < 0.001). The most important factor that influenced FITs to pursue EP was a strong interest in the field. Women were more likely to be influenced by having a female role model (P = 0.001) compared with men. After excluding FITs interested in IC, women who deselected EP were more likely than men to be influenced by greater interest in another field (P = 0.004), radiation concerns (P = 0.001), lack of female role models (P = 0.001), a perceived "old boys' club" culture (P = 0.001) and discrimination/harassment concerns (P = 0.001). CONCLUSIONS: Women are more likely than men to be negatively influenced by many factors when it comes to pursuing EP as a career choice. Addressing those factors will help decrease the gender disparity in the field.

What Knot to Do: Retrieval of a Kinked and Trapped Coronary Catheter.

Diagnostic coronary artery catheter knotting and kinking are uncommon but potentially catastrophic complications. Our case emphasizes the importance of avoiding this problem and provides recommendations for catheter retrieval in the unlikely event of this complication. To our knowledge, the technique used in our case has not been described before. (Level of Difficulty: Intermediate.).

Use of a Dual-Filter Embolic Protection Device for Brachiocephalic Artery Stenting.

A 77-year-old female with peripheral artery disease underwent brachiocephalic artery stenting for right upper extremity claudication. Given a very high atherosclerotic burden seen on CT, a dual-filter embolic protection device (Sentinel, Boston Scientific) was deployed from the right radial artery to protect the right common carotid and subclavian arteries, and therefore the vertebral artery, during the stenting procedure. This case report demonstrates a novel use of this dual-filter device to provide both carotid and vertebral artery embolic protection during brachiocephalic artery intervention.

Antiplatelet therapy in cardiovascular disease.

Antiplatelet therapy has an essential role in the treatment of cardiovascular disease. In this article, we discuss the characteristics of current, new and emerging antiplatelet drugs, their mechanisms of action, and their role in the primary and secondary prevention of cardiovascular disease.

Noninvasive diagnosis of coronary artery bypass graft disease by dobutamine stress real-time myocardial contrast perfusion imaging.

BACKGROUND: The aim of this study was to assess the accuracy of real-time myocardial contrast perfusion imaging (MCPI) during dobutamine stress echocardiography, for the diagnosis of coronary artery bypass graft disease. METHODS: MCPI was performed using commercially available ultrasound contrast agents (Optison or Definity) at rest and at peak dobutamine-atropine stress in 64 patients with previous coronary artery bypass graft. Significant disease was defined as 70% or greater stenosis in one or more grafts or a native nongrafted coronary artery. MCPI was considered diagnostic in the presence of reversible perfusion abnormalities (RPA). RESULTS: Significant stenosis (>or=70% by quantitative angiography) in one or more grafts was detected in 49 patients (77%). RPA were detected in 44 of these patients (sensitivity 90%, confidence interval [CI] 81-98). Significant stenosis was detected in 74 of the 176 bypass grafts (42%). RPA were detected in the distribution of 55 diseased grafts and 21 nondiseased grafts (regional sensitivity 74%, CI 64-84; specificity 79%, CI 71-87; and accuracy 77%, CI 71-84). RPA were detected in two or more vascular distributions in 25 of 33 patients with multivessel stenotic lesions and in 4 of 31 patients without (sensitivity 76%, CI 61-90; specificity 87%, CI 75-99; and accuracy 81%, CI 72-91). CONCLUSION: Dobutamine stress MCPI is a useful technique for the evaluation of coronary artery bypass graft disease.

Comparison of N-acetylcysteine and fenoldopam for preventing contrast-induced nephropathy (CAFCIN).

BACKGROUND: N-acetylcysteine and fenoldopam are commonly prescribed for prevention of contrast mediated nephropathy, however, comparative superiority of either agent is unknown. METHODS: In a prospective, randomized, parallel-group trial, adult cardiac catheterization patients at the university and veterans' hospitals with pre-existing stable renal insufficiency were randomized to N-acetylcysteine 600 mg orally twice daily for 4 doses or fenoldopam 0.1 mcg/kg/min intravenously for a minimum of 8 h. All patients received intravenous hydration with normal saline (5% dextrose in normal saline for diabetics on insulin). Randomization was stratified for diabetes. The primary endpoint was mean change in Scr at 72 h. Secondary endpoint was the incidence of contrast-induced nephropathy (25% increase above baseline Scr or absolute increase of 0.5 mg/dL). RESULTS: Study termination occurred after ninety-five patients (mean age 68+/-10 years, female 25%, diabetic 42%, mean baseline Scr 1.5+/-0.4 mg/dL) were randomized, with 84 completing follow-up (44 N-acetylcysteine, 40 fenoldopam). Overall, there were no significant differences in mean change in Scr at 72 h (N-acetylcysteine 0.20+/-0.72 vs. fenoldopam 0.08+/-0.48 mg/dL, p=0.4) or incidence of contrast-induced nephropathy (N-acetylcysteine 5 vs fenoldopam 8, p=0.4). No differences were detected in subgroup analyses for diabetes, baseline Scr >1.7 or 2.0 mg/dL, gender, age >70 years, or contrast volume >150 mL. Results were similar after multivariate adjustment for diabetes, contrast volume, heart failure and gender. CONCLUSIONS: Our randomized comparison failed to demonstrate a significant difference in the abilities of N-acetylcysteine and fenoldopam to prevent the decline in renal function or the incidence of contrast-induced nephropathy during cardiac catheterization.

Comparison of dobutamine stress echocardiography with and without real-time perfusion imaging for detection of coronary artery disease.

In a pilot study of 27 patients, those who presented with chest pain underwent 2 dobutamine stress echocardiographic studies, 1 with high mechanical index harmonic imaging to analyze wall motion without contrast and 1 with real-time low mechanical index perfusion imaging with intravenous Optison to assess myocardial perfusion and wall motion. All patients then underwent quantitative coronary angiography. Two independent reviewers demonstrated an improvement in sensitivity when analyzing myocardial perfusion. In the 21 patients who had significant coronary stenoses, 14 had abnormal myocardial perfusion detected at peak stress and 7 had abnormal wall motion detected by standard dobutamine stress echocardiography. There was decreased specificity with perfusion imaging by 1 reviewer. The addition of real-time perfusion imaging after intravenous contrast during dobutamine stress echocardiography has the potential to improve detection of coronary artery disease.

Diagnostic accuracy and prognostic value of dobutamine stress myocardial contrast echocardiography in patients with suspected acute coronary syndromes.

BACKGROUND: Both early stress testing and cardiac troponin I (cTnI) measurements are useful in assessing the prognosis of patients with acute coronary syndrome (ACS). We sought to determine the accuracy and prognostic value of wall motion analysis (WMA) and myocardial perfusion analysis (MPA) with real-time myocardial contrast echocardiography (RTMCE) during dobutamine stress in this patient population. METHODS: We performed dobutamine stress RTMCE to assess perfusion in 158 consecutive patients (mean age: 61 +/- 13 years) with chest pain and possible ACS. Of these, 119 had normal cTnI, while 39 had isolated elevations of cTnI (range: 0.5-9.0 ng/ml). Quantitative angiography was performed within 1 month of RTMCE in 61 patients. Patients were followed for 16 months (range: 6-46 months). Cardiac events included death, nonfatal myocardial infarction, recurrent unstable angina, or need for urgent revascularization. RESULTS: The sensitivity, specificity, and accuracy of MPA for detecting a >50% coronary stenosis were 92%, 77%, and 88%, respectively, while they were 62%, 85%, and 67% for WMA. Three-year event-free survival was 87% in patients with negative WMA and MPA, 49% in those with positive WMA and MPA, and 51% in patients with negative WMA but positive MPA. Age-adjusted multivariate analysis demonstrated that the only independent predictors of cardiac events were a positive MPA (hazard ratio = 3.23; 95% CI = 1.23-8.49) and male sex (hazard ratio = 3.29; 95% CI = 1.21-8.97). CONCLUSIONS: In patients suspected of having an ACS, RTMCE improved the accuracy of dobutamine stress echocardiography for detecting coronary artery disease, and was an independent predictor of outcome.

Noninvasive diagnosis of coronary artery disease in patients with diabetes by dobutamine stress real-time myocardial contrast perfusion imaging.

OBJECTIVE: The aim of this study was to assess the accuracy of real-time myocardial contrast perfusion imaging (MCPI) during dobutamine stress in the diagnosis and localization of coronary artery disease (CAD) in patients with diabetes. Myocardial contrast echocardiography is a new technique that allows evaluation of myocardial perfusion. Its utility in diabetic patients has not been defined. RESEARCH DESIGN AND METHODS: Dobutamine-atropine stress test was performed in conjunction with MCPI using Optison or Definity at rest and at peak stress in 128 patients with diabetes and suspected CAD who underwent coronary angiography within 1 month. CAD was defined as > or =50% stenosis in one or more coronary artery. MCPI was considered diagnostic of CAD in the presence of reversible perfusion abnormalities. The normalcy rate of MCPI was additionally determined in 18 asymptomatic nondiabetic patients with low probability. RESULTS: CAD was detected in 101 (79%) patients by angiography. Reversible perfusion abnormalities were detected in 90 patients with and 13 patients without CAD. The overall sensitivity of MCPI was 89% (95% CI 83-95), specificity 52% (33-71), and accuracy 81% (75-88). Reversible abnormalities were detected in two or more vascular distributions in 44 of 56 patients with multivessel CAD and in 8 of 63 patients without (sensitivity 68%, specificity 87%, positive predictive value 84%, and accuracy 79%). Regional sensitivity was 75% (65-85) for left anterior descending CAD, 71% (60-83) for left circumflex, and 67% (55-78) for right CAD. MCPI was normal in 16 of the 18 patients with low clinical probability of CAD (normalcy rate 89%). CONCLUSIONS: MCPI is a useful noninvasive technique for the diagnosis and localization of CAD in diabetic patients. The extent of perfusion abnormalities can identify patients with multivessel CAD with a moderate sensitivity and high specificity.

Safety of dobutamine stress real-time myocardial contrast echocardiography.

OBJECTIVES: The aim of this study was to determine the safety of dobutamine stress myocardial perfusion imaging (MPI) obtained by real-time contrast echocardiography (RTCE) and intravenous ultrasound contrast in a large cohort of patients with suspected coronary artery disease (CAD). BACKGROUND: Despite the increasing number of studies showing the potential clinical utility of myocardial contrast perfusion imaging with commercially available contrast agents, the safety of this technique in a clinical setting has not been demonstrated. METHODS: Over a four-year period, 1,486 patients underwent dobutamine stress RTCE with low mechanical index pulse sequence schemes after intravenous injections of commercially available contrast agents (35% Definity, Bristol Myers Squibb Medical Imaging Inc., North Billerica, Massachusetts; 65% Optison, GE-Amersham, Princeton, New Jersey). The hemodynamic and adverse effects of RTCE were compared with 1,012 patients who underwent conventional dobutamine stress echocardiography (DSE) without contrast. The feasibility of image analysis was defined as the ability to analyze MPI in at least two of the three standard segments in each left ventricular wall. RESULTS: No myocardial infarction or death occurred during dobutamine stress. There was no difference in the incidence of nonsustained ventricular tachycardia, sustained ventricular tachycardia, or supraventricular tachycardia during dobutamine infusion between RTCE and DSE. Myocardial perfusion imaging was considered feasible for analysis in 94% of the walls at baseline and 95% at peak stress. The anterior, lateral, and posterior walls were the most common regions in which MPI was not feasible. Myocardial perfusion imaging with RTCE had a higher accuracy for detecting patients with angiographically significant CAD than the analysis of wall motion (84% vs. 66%, respectively; p < 0.001). CONCLUSIONS: Dobutamine stress RTCE appears to be a safe and feasible technique for evaluating patients with known or suspected CAD.

Comparison of low-mechanical index pulse sequence schemes for detecting myocardial perfusion abnormalities during vasodilator stress echocardiography.

Myocardial contrast echocardiography has the potential to accurately detect functionally significant coronary artery disease during pharmacologic stress testing. Different low-mechanical index modalities, including triggering replenishment imaging (TRI) and real-time imaging (RTI), are currently used to identify myocardial perfusion defects. We compared the ability of TRI with that of RTI for detecting and localizing perfusion abnormalities. Thirty-six patients (62 +/- 14 years old, 15 men) underwent single-photon emission computed tomography (SPECT) with technetium-99m sestamibi and myocardial contrast echocardiography at baseline and after infusion of 0.56 mg/kg of dipyridamole. Sixteen of these patients also underwent quantitative angiography. Contrast-enhanced images were obtained in 4-, 3-, and 2-chamber views after intravenous bolus injections of lipid-encapsulated microbubbles (0.1 ml of Definity). A myocardial perfusion defect was defined by myocardial contrast echocardiography as a delay of >2 seconds in contrast replenishment after high-mechanical index flash impulse. The myocardial segments were divided into 3 major coronary territories. There was agreement in detecting perfusion defects between SPECT and TRI in 26 patients (72%, kappa = 0.46) and between SPECT and RTI in 27 patients (75%, kappa = 0.50). Agreements between myocardial contrast echocardiography and SPECT for localizing coronary territories with perfusion defects were 81% for TRI (kappa = 0.43) and 85% for RTI (kappa = 0.61). Accuracy of RTI for detecting >50% diameter stenoses by quantitative angiography was 79%, that of TRI was 71%, and that of SPECT was 65%. These data indicate that the different low-mechanical index imaging schemes are equivalent to radionuclide SPECT in accurately detecting diseased coronary artery territories during vasodilator stress.

Comparative accuracy of real-time myocardial contrast perfusion imaging and wall motion analysis during dobutamine stress echocardiography for the diagnosis of coronary artery disease.

OBJECTIVE: This study sought to compare the accuracy of myocardial contrast echocardiography (MCE) and wall motion analysis (WMA) during submaximal and peak dobutamine stress echocardiography (DSE) for the diagnosis of coronary artery disease (CAD). BACKGROUND: The relative merits of MCE and WMA for the detection of CAD during DSE have not been studied in a large number of patients. METHODS: We studied 170 patients who underwent dobutamine (up to 50 microg/kg/min)-atropine stress testing and coronary angiography. The WMA and MCE (using repeated boluses of Optison [Mallinckrodt, St. Louis, Missouri] or Definity [Bristol-Myers Squibb, New York, New York]) were performed at rest, at intermediate stress (65% to 75% of maximal heart rate), and at peak stress. The diagnosis of CAD (>/=50% stenosis in >/=1 coronary artery) was based on reversible wall motion and perfusion abnormalities. RESULTS: Coronary artery disease was detected in 127 (75%) patients. Sensitivity of MCE was higher than that of WMA at maximal stress (91% vs. 70%; p = 0.001) and at intermediate stress (84% vs. 20%; p = 0.0001). Specificity was lower for MCE compared with WMA (51% vs. 74%; p = 0.01). Overall accuracy was higher for MCE than for WMA (81% vs. 71%; p = 0.01). Sensitivity for detection of CAD based on abnormalities in >/=2 vascular regions was higher for MCE than for WMA (67% vs. 28%; p < 0.01). CONCLUSIONS: The majority of inducible perfusion abnormalities occur at an intermediate phase of the stress test, without wall motion abnormalities. Myocardial contrast echocardiography provides better sensitivity than WMA, particularly in patients with submaximal stress and in identifying patients with multivessel CAD.