Prognostic Value of 6-Minute Walk Distance in Patients Undergoing Percutaneous Coronary Intervention: a Veterans Affairs Prospective Study.

The 6-minute walk distance (6MWD) test is a useful prognostic tool in chronic heart failure. Its usefulness after percutaneous coronary intervention is unknown. In a prospective observational study, patients underwent a 6MWD test within 2 weeks after percutaneous coronary intervention. The primary endpoint was major adverse cardiovascular events (MACE) (death, acute coronary syndrome, and heart failure admission) at one year. Receiver operating characteristic curves and area under the curve were used to determine the 6MWD test's predictive power, and the Youden index was used to measure its effectiveness. A total of 212 patients were enrolled (98% men; mean age, 65 ± 9 yr). Major comorbidities were hypertension in 187 patients (88%), dyslipidemia in 186 (88%), and diabetes mellitus in 95 (45%). Among the 176 patients (83%) who completed the 6MWD test, the incidence of MACE at one year was 22% (acute coronary syndrome in 17%; heart failure admission in 4%; and death in 3%). The area under the curve for MACE was 0.59, and 6MWD was shorter for patients with MACE than for those without (290 vs 326 m; P=0.03). For 39 patients with previous heart failure who completed the 6MWD test, the area under the curve was 0.64 for MACE and 0.78 for heart failure admission. The 6MWD test predicted reasonably well the incidence of MACE one year after percutaneous coronary intervention. In a subgroup of patients with previous heart failure, it fared even better in predicting heart failure admission. Larger studies are needed to confirm these findings.

Transcatheter aortic valve replacement 24 years after cardiac transplantation.

As patient survival after cardiac transplantation has improved over the course of the last several decades, clinicians are now faced with late complications. This includes aortic stenosis which, traditionally, has been treated with reoperative sternotomy and aortic valve replacement. Transcather aortic valve replacement (TAVR) offers a minimally invasive alternative in this high-risk population. A small but growing number of cases of TAVR after heart transplantation in high-risk patients have been reported in the last 10 years; we now present a case of aortic valve replacement via a transcatheter approach 24 years after cardiac transplantation.

Axillary Artery Hemostasis Post-Intra-Aortic Balloon Pump Failure.

Intra-aortic balloon pump via the axillary approach has been increasingly utilized to facilitate physical rehabilitation prior to definitive heart failure therapy. There is a high risk of device fracture with loss of arterial accessibility. Three cases are presented that demonstrate innovative arteriotomy hemostasis techniques for malfunctioning axillary intra-aortic balloon pumps. (Level of Difficulty: Intermediate.).

Impact of Valve Size on Prosthesis-Patient Mismatch and Aortic Valve Gradient After Transcatheter versus Surgical Aortic Valve Replacement.

OBJECTIVE: Limited data is available about the effect of implanted valve size on prosthesis-patient mismatch (PPM) incidence and aortic gradient (AG) after transcatheter aortic valve replacement (TAVR) and surgical aortic valve replacement (SAVR). We compared PPM incidence and postprocedural AG between TAVR and SAVR patients considering the impact of implanted valve size. METHODS: From March 20, 2012, to September 30, 2015, 563 consecutive patients underwent TAVR (n = 419) or isolated SAVR (n = 144). Postprocedural transthoracic echocardiography was obtained within 30 days; AG, effective orifice area (EOA), and EOA index were calculated. RESULTS: A total of 381 patients in TAVR group and 82 patients in SAVR group were included. Mean preoperative AG and mean aortic valve area were not significantly different between the 2 groups. Postprocedural AG was significantly lower in TAVR than SAVR group, 7.74 ± 5.39 versus 14.27 ± 8.16 (P < 0.001). Between patients who had TAVR and SAVR with a valve size ≤23 mm, SAVR patients were 3 times more likely to have greater than mild AG after the procedure, OR: 3.1 (95% CI, 1.1 to 8.9) (P < 0.001). PPM incidence was significantly higher in SAVR group than TAVR group, 44 (53.7%) versus 112 (29.4%), OR = 2.8 (95% CI, 1.7 to 4.5) (P < 0.001). The PPM incidence was also higher in SAVR group than TAVR group among those who had the procedures with a valve size ≤23 mm, 35 (64.8%) versus 56 (47.9%), OR = 2 (95% CI, 1.1 to 3.9) (P = 0.048). Postprocedural outcomes were comparable between the 2 groups. CONCLUSIONS: In comparison to SAVR, TAVR is associated with less PPM and lower AG, especially in patients receiving a valve size ≤23 mm.

Outcomes of Direct Transcatheter Aortic Valve Replacement Without Balloon Aortic Valvuloplasty Using a New Generation Valve.

PURPOSE: We investigated the outcomes of patients who underwent Transcatheter Aortic Valve Replacement (TAVR) with and without Balloon Aortic Valvuloplasty (BAV) using the SAPIEN 3 (S3) valve. METHODS: All patients who underwent TAVR using S3 valve were included. The primary outcomes were the incidence of stroke and significant paravalvular leak (PVL). Secondary outcomes were the incidence of mortality, balloon post dilation, and need for permanent pacemaker. RESULTS: From July-2014 to April-2018, 34 (9%) patients underwent BAV prior to TAVR and 344 (91%) patients underwent direct TAVR without BAV using the S3 valve. The Society of Thoracic Surgeons (STS) risk score was similar between two groups; 5.8 ±â€¯3.5 in no BAV group and 5.4 ±â€¯3.3 in BAV group, p = 0.53. After TAVR, 6 (1.7%) patients in no BAV group but no patient in BAV group developed stroke (p = 1.0). No patient had severe PVL and only 5 patients (1.3%) had moderate PVL at 30-day; 4 (1.2%) in no BAV group and 1 (2.9%) in BAV group (p = 0.38). Forty-six patients (13.4%) in the no BAV group and 4 (11.8%) patients in the BAV group needed balloon post dilation (p = 1.0). Six (1.6%) patients died during hospitalization, all in the no BAV group (p = 1.0). Forty-five (11.9%) patients needed new pacemaker implantation; 44 (12.8%) patients in no BAV group and 1 (2.9%) patient in BAV group (p = 0.1). Two-year survival rate was 85% in no BAV group and 84% in BAV group (p = 0.46). CONCLUSIONS: TAVR using S3 valves is associated with very low rates of post-TAVR stroke and significant PVL. Outcomes of direct TAVR are similar to the outcomes of TAVR with BAV, without an increased rate of stroke, significant PVL, or balloon post dilation.

Length of Stay After Transfemoral Transcatheter Aortic Valve Replacement: An Analysis of the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry.

OBJECTIVES: The goal of this study was to investigate the trends, predictors, and outcomes of delayed discharge (>72 h) after transcatheter aortic valve replacement. BACKGROUND: Length of stay post-transcatheter aortic valve replacement may have significant clinical and administrative implications. METHODS: Data from the Transcatheter Valve Therapy Registry were used to identify patients undergoing nonaborted transfemoral transcatheter aortic valve replacement who survived to discharge, and data linked from the Centers for Medicare & Medicaid Services were used to provide 1-year events. Patients were categorized to early discharge (≤72 h) versus delayed discharge (>72 h). The trends, predictors, and adjusted 1-year outcomes were compared in both groups. RESULTS: From 2011 to 2015, a total of 13,389 patients (55.1%) were discharged within 72 h, whereas 10,896 patients (44.9%) were discharged beyond 72 h. There was a significant decline in rates of delayed discharge across the study period (62% vs. 34%; p < 0.01). This remained unchanged when stratified by Transcatheter Valve Therapy risk scores. Several factors were identified as independent predictors of early and delayed discharge. After adjustment for in-hospital complications, delayed discharge was an independent predictor of 1-year all-cause mortality (hazard ratio: 1.45; 95% confidence interval: 1.30 to 1.60; p < 0.01). CONCLUSIONS: Rates of delayed discharge have declined from 2011 to 2015. Delayed discharge is associated with a significant increase in mortality even after adjusting for in-hospital complications. Further work is necessary to determine if predictors of early discharge could be used to develop length of stay scores that might be instrumental in administrative, financial, or clinical policy development.

Drug-Eluting Balloons Versus Everolimus-Eluting Stents for In-Stent Restenosis: A Meta-Analysis of Randomized Trials.

OBJECTIVES: Individual randomized trials comparing drug-eluting balloons (DEB) versus everolimus-eluting stents (EES) for in-stent restenosis (ISR) were underpowered for clinical end-points. The objective of this study was to compare the clinical outcomes of DEB versus EES for any ISR. MATERIALS & METHODS: Electronic databases were searched for randomized trials which compared DEB versus EES for any ISR (i.e., drug eluting or bare metal stents). Summary estimate risk ratios (RRs) were constructed using a DerSimonian and Laird random effects model. RESULTS: Five trials with 962 patients were included. In-segment minimum lumen diameter (MLD) was lower with DEB (standardized mean difference -0.24, 95% confidence interval [CI] -0.46 - -0.01) on angiographic follow-up at a mean of 8.6 months. There was no statistically significant difference in the risk of target vessel revascularization (TVR) at 1 year (RR 1.15, 95% CI 0.60-2.19), but TVR was increased with DEB at 3 years (RR 1.87, 95% CI 1.15-3.03). The risk of target lesion revascularization (TLR) was statistically increased with DEB (RR 2.17, 95% CI 1.13-4.19) at a mean of 24.4 months. There was no difference in the risk of MI, stent thrombosis, cardiac mortality and all-cause mortality between both groups. CONCLUSION: In patients with any type of ISR, DEB was associated a similar risk of TVR at 1-year, but increased risk of TVR and TLR at longer follow-up, as compared with EES. The quality of evidence was moderate, suggesting the need for further randomized trials with longer follow-up to confirm the role of DEB in the management of ISR.

Transcatheter Aortic Valve Replacement: Efficiency and Safety Improvements With Progressive Experience and Improved Technology.

OBJECTIVE: Transcatheter aortic valve replacement is now commercially available for intermediate-risk, high-risk, or inoperable patients with severe aortic stenosis. In this study, we investigated change in the safety and efficiency of the transcatheter aortic valve replacement procedure at our institution and patient outcomes comparing our first 100, second 100, and last 100 patients. METHODS: From March 2012 to June 2016, 544 patients underwent transcatheter aortic valve replacement at our center. Three hundred patients were selected for this study and were categorized in the following three groups: group A, first to 100th patient; group B, 101st to 200th patient; and group C, 444th to 544th patient. Preoperative, intraoperative, and postoperative data were collected. RESULTS: Three hundred patients, 162 male (54%) male and 138 female (46%) with a mean ± SD age of 79.10 ± 8.93 years and mean ± SD society of thoracic surgeons' risk score of 7.47 ± 0.76 were included. Fluoroscopy time, operation time, and incision time significantly decreased form group A to group C (all P < 0.05). Mean of contrast volume was also the highest in group A and the lowest in group C (P < 0.001). Acute kidney injury rate was 26% (n = 26) in group A versus 23% (n = 23) in group B (P = 0.743), and only one patient in group C (group C vs. group B, P < 0.001). Strokes declined over time: five (5%) stroke in group A; two (2%) stroke in group B, and no patient in group C (group C vs. group B, P = 0.1, and group C vs. group A, P = 0.059). In-hospital mortality was 5% (n = 5) in group A, 4% (n = 4) in group B, and 1% in group C (P = 0.21). CONCLUSIONS: Progressive experience and technology advances with transcatheter aortic valve replacement procedures improved operators' expertise, making the transcatheter aortic valve replacement more efficient and safer over time.

Prevalence, Causes, and Predictors of 30-Day Readmissions Following Hospitalization With Acute Myocardial Infarction Complicated By Cardiogenic Shock: Findings From the 2013-2014 National Readmissions Database.

BACKGROUND: Prior studies have shown that survivors of acute myocardial infarction (AMI) complicated by cardiogenic shock are likely to have increased risk of readmissions in the early post-discharge period. However, the contemporary prevalence, reasons, and predictors of 30-day readmissions are not well known. METHODS AND RESULTS: Hospitalizations for a primary diagnosis of AMI complicated by cardiogenic shock, and discharged alive, were identified in the 2013 and 2014 Nationwide Readmissions Databases. Prevalence and reasons for 30-day unplanned readmissions were investigated. A hierarchical logistic regression model was used to identify independent predictors of 30-day readmissions. Among 1 116 933 patient hospitalizations with AMI, 39 807 (3.6%) had cardiogenic shock and were discharged alive. Their 30-day readmission rate was 18.6%, with a median time for readmission 10 days post discharge. Predictors of readmission included: non-ST-segment elevation myocardial infarction, female sex, low-income status, nonprivate insurance, chronic renal failure, long-term ventricular assist device or intra-aortic balloon placement, and tachyarrhythmia. The majority of readmissions were attributable to cardiac-related causes (52%); heart failure being the most frequent cardiac cause (39% of all cardiac causes). Noncardiac-related readmissions included infections (14.9%), bleeding (5.3%), and respiratory causes (4.9%). The median cost per readmission was $9473 US dollars ($5037-20 199). CONCLUSIONS: Among survivors of AMI complicated by cardiogenic shock who were discharged from hospital, almost 1 in 5 are readmitted at 30 days, mainly because of cardiac reasons such as heart failure and new AMI. The risk of readmission was associated with certain baseline patient/hospital characteristics.

Safety and Efficacy of Dual Versus Triple Antithrombotic Therapy in Patients Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Choosing an antithrombotic regimen after coronary intervention in patients with concomitant indication for anticoagulation is a challenge commonly encountered by clinicians. METHODS: We performed a meta-analysis of observational studies and randomized, controlled trials comparing outcomes of triple therapy (dual antiplatelet therapy and anticoagulant) with dual therapy (single antiplatelet therapy and anticoagulant) in patients taking long-term anticoagulants after percutaneous coronary intervention. Major bleeding was the primary outcome. Random effects overall risk ratios (RRs) were calculated using the DerSimonian and Laird model. RESULTS: Nine observational studies and 2 randomized controlled trials with a total of 7276 patients met our selection criteria. At a mean follow-up of 10.8 months major bleeding was higher in the triple therapy cohort compared with dual therapy (6.6% vs 3.8%; RR 1.54; 95% confidence interval [CI], 1.2-1.98; P <.01). No difference was observed between the 2 groups for all-cause mortality (RR 0.98; 95% CI, 0.68-1.43; P = .93), major adverse cardiac events (RR 1.03; 95% CI, 0.8-1.32; P = .83), thromboembolic events (RR 1.02; 95% CI, 0.49-2.10; P = .96), myocardial infarction (RR 0.85; 95% CI, 0.67-1.09; P = .21), stent thrombosis (RR 0.77; 95% CI, 0.46-1.3; P = .33), and target vessel revascularization (RR 0.87; 95% CI, 0.66-1.15; P = .33). CONCLUSION: In patients receiving anticoagulant therapy, a strategy of single antiplatelet therapy confers a benefit of less major bleeding with no difference in all-cause mortality, cardiovascular mortality, major adverse cardiac events, myocardial infarction, stent thrombosis, or thromboembolic event rate compared with dual antiplatelet therapy.

Bleeding complications of triple antithrombotic therapy after percutaneous coronary interventions.

BACKGROUND: 5% of patients undergoing coronary stenting have an indication for anticoagulation. The aim of our study was to determine the bleeding rates and complications in patients on triple oral antithrombotic therapy (TOAT) after coronary stenting. METHODS: We studied patients who underwent coronary stenting in our institution between 2003-2013 and were started on TOAT. Bleeding was the primary outcome. RESULTS: Totally, 999 patients were treated with TOAT with a median follow up of 127 days. All patients were treated with warfarin as an anticoagulant. 267 patients (26.7%) developed a total of 331 bleeding events. 100 patients had bleeding during the first 30 days of therapy. Major bleeding, minor bleeding, bleeding requiring medical attention, and minimal bleeding developed in 2.9%, 3.3%, 17.2%, and 3.3% of the patients respectively as their most significant bleeding event. Patients with anticoagulation initiated at time of stenting had a significantly higher bleeding rate compared to those already on chronic anticoagulation [adjusted HR (95% CI): 1.37 (1.03-1.79), P = 0.03]. The bleeding likelihood was significantly higher for patients with drug-eluted stents (DES) compared to bare-metal stents (BMS) [adjusted OR (95% CI): 1.52 (1.14 - 2.04), P < 0.05]. Patients with atrial fibrillation had an increased rate of bleeding after 6 month of initiation of TOAT with significantly worse outcomes. CONCLUSIONS: TOAT after coronary stenting is associated with high bleeding rates. Patients with AF had worse outcomes. Patients with newly initiated anticoagulation at time of stenting bleed significantly more than people already on chronic anticoagulation prior to stenting. © 2016 Wiley Periodicals, Inc.

Two-Decade Trends in the Prevalence of Atherosclerotic Risk Factors, Coronary Plaque Morphology, and Outcomes in Adults Aged ≤45 Years Undergoing Percutaneous Coronary Intervention.

Data are limited about the prevalence trends of risk factors, lesion morphology, and clinical outcomes of coronary artery disease in patients, aged ≤45 years, undergoing percutaneous coronary intervention (PCI), between the bare-metal stent (BMS; 1994 to 2002) and drug-eluting stent (DES; 2003 to 2012) eras. From the PCI database at the Cleveland Clinic, we identified 1,640 patients aged ≤45 years and without a history of coronary artery bypass grafting who underwent PCI from 1994 to 2012. There were 883 patients in the BMS era cohort with a mean follow-up period of 13.15 years and 757 in the DES era cohort with a mean follow-up of 5.02 years. The DES era had more obese (51.8% vs 44.7%, p <0.001) and diabetes (23.0% vs 19.5%, p = 0.09) patients. DES era patients had more B2/C lesions (74.0% vs 32.5%, p <0.001), more severe preprocedural stenosis (86.1 ± 12.9 vs 72.2 ± 21.3, p <0.001), and longer lesions (15.5 ± 9.9 vs 9.6 ± 6.8, p <0.001). No difference was observed in the 30-day mortality between the DES and BMS eras. Irrespective of era, diabetics had worse long-term mortality (19.4% vs 9.3%, p <0.001) compared with nondiabetics. Obese patients had similar long-term outcomes compared with nonobese patients. In conclusion, patients aged ≤45 years, who underwent a PCI procedure in the DES era had worse risk factor profiles, including obesity, compared with patients in the BMS era. They also had more complex lesions. Procedural and long-term outcomes of these patients have not changed between the 2 eras. Young diabetic patients have worse long-term outcomes compared with nondiabetics.

Prescription of Guideline-Based Medical Therapies at Discharge After Carotid Artery Stenting and Endarterectomy: An NCDR Analysis.

BACKGROUND AND PURPOSE: Carotid artery revascularization was previously found to incrementally reduce stroke risk among patients with carotid stenosis treated with medical therapy. However, the frequency with which optimal medical therapies are used at discharge after carotid endarterectomy (CEA) and carotid artery stenting (CAS) is not known, and the influence of patient, operator, and hospital characteristics on the likelihood of prescription is poorly understood. METHODS: In a retrospective cohort study of 23 112 patients undergoing CAS or CEA between January 2007 and June 2012 at US hospitals participating in the CARE registry (Carotid Artery Revascularization and Endarterectomy), we examined antiplatelet therapy and statin utilization at discharge. Hierarchical multivariable logistic regression was used in adjusted analyses. RESULTS: Antiplatelet agents and statins were prescribed at discharge in 99% and 78%, respectively, after CAS and 93% and 75%, respectively, after CEA. After adjustment, antiplatelet therapy was more often prescribed after CAS than CEA (odds ratio 2.4 [95% confidence interval 1.68-3.45]), but statin prescription was equally likely (odds ratio 1.11 [95% confidence interval 0.84-1.49]). Operator specialty (medical>radiology/surgery) and hospital community setting (suburban>urban>rural) independently predicted antiplatelet and statin agent use at discharge, whereas hospital geographic location (Northeast>Midwest/South>West) predicted use of statins but not antiplatelet therapy at discharge. CONCLUSIONS: US antiplatelet agent and statin discharge prescription rates were suboptimal after both CAS and CEA and varied by revascularization modality, operating physician specialty, and hospital characteristics. Improved and more uniform utilization after these procedures will be critical to the success of comprehensive stroke risk reduction efforts.

Thyrotoxic Periodic Paralysis: A Concise Review of the Literature.

BACKGROUND: Thyrotoxic periodic paralysis (TPP) is a rare disease entity highlighted by hypokalemia, flaccid paralysis, and thyrotoxicosis. It usually presents as sudden profound muscle weakness manifested as almost complete immobility and can affect proximal and distal limb muscles, respiratory musculature as well as the cardiac conduction system. METHODS: A comprehensive review of Thyrotoxic periodic paralysis from 1885 to date was carried out by an extensive and thorough literature research including but not limited to Pubmed, Medline and EMBASE. OBJECTIVE: This review emphasizes the etiology, pathogenesis, management and prognosis of TPP and aims to highlight clinical awareness of early diagnosis and rapid initiation of treatment. CONCLUSION: It is extremely important to diagnose this condition as early as possible as it is potentially reversible and prompt treatment leads to rapid resolution with no residual weakness. Missing the diagnosis can result in possible fatal complications such as hypercapneic respiratory failure and ventricular fibrillation.

Temporal Trends and Outcomes of Patients Undergoing Percutaneous Coronary Interventions for Cardiogenic Shock in the Setting of Acute Myocardial Infarction: A Report From the CathPCI Registry.

OBJECTIVES: The purpose of this study was to examine the temporal trends in demographics, clinical characteristics, management strategies, and in-hospital outcomes in patients with acute myocardial infarction complicated by cardiogenic shock (CS-AMI) who underwent percutaneous coronary intervention (PCI) from the Cath-PCI Registry (2005 to 2013). BACKGROUND: The authors examined contemporary use and outcomes of PCI in patients with CS-AMI. METHODS: The authors used the Cath-PCI Registry to evaluate 56,497 patients (January 2005 to December 2013) undergoing PCI for CS-AMI. Temporal trends in clinical variables and outcomes were assessed. RESULTS: Compared with cases performed from 2005 to 2006, CS-AMI patients receiving PCI from 2011 to 2013 were more likely to have diabetes, hypertension, dyslipidemia, previous PCI, dialysis, but less likely to have chronic lung disease, peripheral vascular disease, or heart failure within 2 weeks (p < 0.01). Between 2005 and 2006 to 2011 and 2013, intra-aortic balloon pump use decreased (49.5% to 44.9%; p < 0.01), drug-eluting stent use declined (65% to 46%; p < 0.01), and the use of bivalirudin increased (12.6% to 45.6%). Adjusted in-hospital mortality; increased (27.6% in 2005 to 2006 vs. 30.6% in 2011 to 2013, adjusted odds ratio: 1.09, 95% confidence interval: 1.005 to .173; p = 0.04) for patients who were managed with an early invasive strategy (<24 h from symptoms). CONCLUSIONS: Our study shows that despite the evolution of medical technology and use of contemporary therapeutic measures, in-hospital mortality in CS-AMI patients who are managed invasively continues to rise. Additional research and targeted efforts are indicated to improve outcomes in this high-risk cohort.

SCAI/SVM expert consensus statement on carotid stenting: Training and credentialing for carotid stenting.

Carotid artery stenting (CAS) has become an integral part of the therapeutic armamentarium offered by cardiovascular medicine programs for the prevention of stroke. The purpose of this expert consensus statement is to provide physician training and credentialing guidance to facilitate the safe and effective incorporation of CAS into clinical practice within these programs. Since publication of the 2005 Clinical Competence Statement on Carotid Stenting, there has been substantial device innovation, publication of numerous clinical trials and observational studies, accumulation of extensive real-world clinical experience and widespread participation in robust national quality improvement initiatives [5]. Collectively, these advances have led to substantial evolution in the selection of appropriate patients, as well as in the cognitive, technical and clinical skills required to perform safe and effective CAS. Herein, we summarize published guidelines, describe training pathways, outline elements of competency, offer strategies for tracking outcomes, specify facility, equipment and personnel requirements, and propose criteria for maintenance of CAS competency.

Bioresorbable Stents: Is This Where We Are Headed?

Current drug-eluting stents (DES) have shown excellent safety and efficacy in various clinical settings. However, the presence of a permanent metallic scaffold remains an Achilles heel, with concerns for late stent thrombosis and the need for prolonged dual anti-platelet therapy. The bioresorbable vascular scaffold (BRS) has been termed the fourth revolution in interventional cardiology, with an ability to not only treat the coronary lesion, but also restore endothelial function after complete absorption. The absence of a permanent scaffold after months of implantation has the potential to overcome the shortcomings of current metallic DES and markedly impact interventional cardiology practice around the world. This review article focuses on the history, development and clinical studies on various BRS and attempts to predict how this technology could impact future cardiology practice.