Diagnosis of Coronary Stent Dislodgement With Transthoracic Echocardiogram: A Case Report.

Coronary stent dislodgment is a rare complication of percutaneous coronary intervention (PCI). Although stent dislodgment typically occurs immediately in the intraoperative or perioperative period, it can infrequently occur subacutely in the post-operative period. Diagnosis of stent dislodgment can be seen with various cardiac imaging modalities, from transthoracic and transesophageal echocardiogram to cardiac computed tomography or magnetic resonance imaging to direct visualization on fluoroscopy during cardiac catheterization. Given the rarity of this entity, there is a lack of established common practice, gold standard for treatment, and/or procedural data. Instances are managed on a case-by-case basis, using the imaging modalities readily available at the institution and treatment modalities the interventionalist or surgeon is most comfortable with. Therefore, management of stent dislodgment consists of conservative, percutaneous, or surgical interventions on a case-by-case basis. We present a case of right coronary artery stent migration that was incidentally diagnosed with routine transthoracic echocardiogram.

Activation of the endogenous coagulation system in patients with atrial flutter: relationship to echocardiographic markers of thromboembolic risk.

BACKGROUND: Atrial thrombus formation in patients with atrial flutter raises concerns of stroke risk. We investigated patients with isthmus-dependent atrial flutter for coagulation abnormalities before and after cardioversion to sinus rhythm by catheter ablation, and evaluated the relationship of the abnormalities to the echocardiographic risk markers of stroke. METHODS AND RESULTS: Plasma samples were drawn prior to insertion of catheters, immediately after the procedure, and 24 hours afterwards. At baseline, coagulation abnormalities were found in 22 out of 25 patients (88%). von Willebrand factor antigen (vWF-Ag) and factor VIII:C were elevated in 17 patients (68%) and 15 patients (60%), respectively. At baseline, mean plasma levels of vWF-Ag (250.1 +/- 144.4%) and factor VIII:C (215.0 +/- 77.1%) were increased. Key markers of thrombin generation, thrombin-antithrombin III complex (TAT; 47.8 +/- 30.9 microg/L vs 14.5 +/- 13.8 microg/L; p < 0.05) and prothrombin fragments 1.2 (F1.2; 2.5 +/- 0.5 nmoL/L vs 1.2 +/- 1.0 nmoL/L) were significantly elevated in the presence of spontaneous echo contrast. Further, both markers of thrombin generation inversely correlated with left atrial appendage emptying velocity (r = -0.42 and -0.63, p < 0.05). Levels of TAT and F1.2 increased after conversion and ablation. CONCLUSIONS: Endothelial-dependent coagulation factors were enhanced in most patients with atrial flutter. Spontaneous echo contrast and decreased atrial contractility were associated with increased thrombin generation. After conversion and ablation, an increase in thrombin generation and fibrinolysis suggest a transient pro-thrombotic state.

Relation of 12-lead electrocardiogram patterns to implanted defibrillator-terminated ventricular tachyarrhythmias in hypertrophic cardiomyopathy.

Electrocardiographic (ECG) abnormalities are common in hypertrophic cardiomyopathy (HC) and have been associated with the distribution of left ventricular hypertrophy and myocardial fibrosis. Such abnormalities may predispose patients to electrophysiologic instability, ventricular arrhythmias, and sudden cardiac death (SCD). We studied 330 patients with HC who were judged clinically to be at high risk for SCD and therefore received automatic implantable cardioverter-defibrillators (ICDs). Surface 12-lead electrocardiograms acquired at the time of ICD implantation were analyzed and the ECG characteristics of patients with appropriate device interventions for ventricular tachycardia and fibrillation were compared to those patients without appropriate device interventions. The 330 patients were followed for 3.7 +/- 3.0 years after implantation and 57 patients (17%) had appropriate discharges. No differences in the ECG characteristics of patients with and without appropriate device interventions were identified. Markedly increased ECG voltages, QRS duration, left or rightward QRS axis, abnormal Q waves, and QTc or QT dispersion were not associated with appropriate ICD discharge. Conversely, normal electrocardiograms and electrocardiograms normal except for a repolarization abnormality in only 1 anatomic distribution were not associated with freedom from ICD discharge. Moreover, no combination of ECG variables was associated with the likelihood of an appropriate ICD discharge. In conclusion, in a cohort of patients with HC selected because of their high risk for SCD, 12-lead surface electrocardiogram did not predict subsequent appropriate ICD intervention for ventricular tachyarrhythmias and was not useful in risk stratification for sudden death.

The utility of 12-lead Holter monitoring in patients with permanent atrial fibrillation for the identification of nonresponders after cardiac resynchronization therapy.

OBJECTIVES: This study sought to determine the incidence of ineffective capture using 12-lead Holter monitoring and to assess whether this affects response to cardiac resynchronization therapy (CRT). BACKGROUND: Cardiac resynchronization therapy is used in patients with atrial fibrillation (AF), prolonged QRS duration, and heart failure in the setting of ventricular dysfunction. The percentage of ventricular pacing is used as an indicator of adequate biventricular (BiV) pacing. Although device counters show a high pacing percentage, there may be ineffective capture because of underlying fusion and pseudo-fusion beats. METHODS: We identified 19 patients (age 72 +/- 8 years, ejection fraction 18 +/- 5%), with permanent AF who underwent CRT. All patients received digoxin, beta-blockers, and amiodarone for rate control; device interrogation showed >90% BiV pacing. Patients had a 12-lead Holter monitor to assess the presence of effective (>90% fully paced beats/24 h) pacing. At 12 months post-CRT, the New York Heart Association functional class was reassessed and an echocardiogram was obtained and compared with pre-CRT. RESULTS: Only 9 (47%) patients had effective pacing. The other 10 (53%) patients had 16.4 +/- 4.6% fusion and 23.5 +/- 8.7% pseudo-fusion beats. Long-term responders (> or =1 New York Heart Association functional class improvement) to CRT had a significantly higher percentage of fully paced beats (86.4 +/- 17.1% vs. 66.8 +/- 19.1%; p = 0.03) than nonresponders. CONCLUSIONS: Pacing counters overestimate the degree of effective BiV pacing in patients with permanent AF undergoing CRT therapy. Only patients with complete capture responded clinically to CRT. These findings have important implications for the application of CRT to patients with permanent AF and heart failure.

Long-term outcome following successful pulmonary vein isolation: pattern and prediction of very late recurrence.

BACKGROUND: Despite encouraging results of pulmonary vein isolation (PVI) ablation for atrial fibrillation (AF), it is unclear whether there is genuine cure or there is an important attrition rate. We sought to determine the long-term outcome of the initial responders who experienced a prolonged AF-free complete response. METHODS: From a series of 350 consecutive patients who underwent PVI for AF, 264 patients (75%) (males 71%, age 57 +/- 12 years, paroxysmal AF 87%) who demonstrated >or=1 year AF-free follow-up on no antiarrhythmic drugs were followed for 1-5 years. RESULTS: During 28 +/- 12 months follow-up, 23 of 264 (8.7%) patients had recurrence of AF. The actuarial recurrence at 2 years postablation was 5.8% and increased to 25.5% at 5 years. Compared with long-term responders, more patients with late recurrence had hypertension (HR = 2.18, P = 0.009) and hyperlipidemia (HR = 4.01, P = 0.0005). Among 18 patients with recurrent AF necessitating repeat PVI, 15 (83%) required re-isolation of > 1 PV and 28 of 45 (58%) PVs showed reconnection. All PVs were re-isolated and five (28%) patients had additional linear ablation. All 15 patients became AF-free again. CONCLUSIONS: Although most patients following PVI remain AF-free, some patients develop "late" recurrence of AF. The "late" recurrence patients are more likely to have hypertension and hyperlipidemia. Most late recurrences are associated with PV reconnections. Our observations emphasize the importance of continued long-term vigilance for AF recurrence, and also raise concerns regarding the need for long-term anticoagulation therapy.

Acute conversion of persistent atrial fibrillation during dofetilide initiation.

BACKGROUND: Dofetilide (D) is a highly selective blocker of the rapid component of the delayed rectifier potassium current and was approved for the treatment of atrial fibrillation (AF) based on a satisfactory safety/efficacy profile from trials in patients with left ventricle (LV) dysfunction or heart failure. The dose-dependant acute conversion rates (<72 hours) were reported to be in the range of 6-30%. We hypothesized that the acute pharmacological conversion rate of D is higher than previously reported if used in a healthier cohort of patients with persistent AF. METHODS AND RESULTS: Eighty consecutive patients received D dosing per Cockroft-Gault adjustment for creatinine clearance and QTc intervals. Patients were 61 +/- 10 years, 79% male, ejection fraction (EF) 53 +/- 13%, coronary artery disease 20%, and left atrial dimension 4.1 +/- 0.2 cms. The duration of the treated AF episode was a median of 19 days (range 10-113 days). All patients received D while on telemetry for at least six dosing intervals. After 2.2 +/- 1.2 doses, 77% of patients converted to sinus rhythm (SR) and 23% did not and required direct current (DC) cardioversion. Acute pharmacological conversion rates were: 20% for D 125 mcg bid, 44% for 250 mcg bid, and 85% for 500 mcg bid. None of the patients had torsade de pointes and none had to stop D for intolerance. Failure to convert to SR on D alone was associated with larger left atrium (LA) diameter (P = 0.04), longer duration of AF (P = 0.02), and use of lower dosages of D (P = 0.04). CONCLUSIONS: D had an unusually high pharmacological conversion rate, demonstrated an incremental dose response, and was well tolerated and safe, in a relatively healthy adult cohort with persistent AF. In addition to D dose, pharmaco-conversion was predicted by LA size and AF duration. D is a desirable alternative for conversion of AF in a variety of clinical settings.

Syncope, other risk factors, and the implantable defibrillator for sudden death prevention in hypertrophic cardiomyopathy.

Sudden cardiac death is the most devastating complication of hypertrophic cardiomyopathy. Since HCM may present at young age, and since the risk period for sudden arrhythmic death may be long, decision-making in HCM patients may be difficult, and have lifelong implications. Community based studies show a sudden death mortality of approximately 1%/year. Certain patients can be identified by their clinical characteristics, and through testing, to have higher annual risk, as high as 4-5%/year. Risk factors sudden cardiac death include: family history of HCM and sudden death, recurrent syncope, ventricular tachycardia, as detected by Holter monitoring or exercise testing, subnormal (<20 mmHg) increase in systolic blood pressure on maximal exercise testing and lastly marked (especially >30 mm) left ventricular hypertrophy. The implantable defibrillator has been shown to avert sudden death in selected HCM patients deemed to be at high risk.

Use of admission troponin in critically ill medical patients.

Serum troponin I (TnI) is a sensitive marker of cardiac injury. A relation between elevated TnI and mortality has been suggested. In this retrospective chart review of 221 patients admitted to the medical intensive care unit (MICU) during a 6-month period, the authors studied the use of admission TnI levels in predicting mortality in MICU-admitted patients. Data retrieved included demographics, admission diagnosis, troponin, electrocardiogram, Acute Physiology and Chronic Health Evaluation (APACHE) II score, echocardiogram, requirements for mechanical ventilation and vasopressor support, development of multiorgan failure, mortality, and discharge disposition. There were 132 patients for whom TnI level was sent within 24 hours of admission; these patients comprised the study group. The median age was 70 years; 59% were female. The mean APACHE II score was 22. Troponin I was positive in 31% of patients (median level, 0.4 Ug/L; range 0-358 Ug/L). The hospital mortality was 39%. Positive TnI showed a weak association with intensive care unit (ICU) mortality (P = .049) but not with overall mortality. There was no significant correlation between admission TnI concentration and APACHE II score (P = .33), administration of vasopressor medications (P = .115), or development of multiorgan failure (P = .64). The authors concluded that there is no benefit in obtaining a routine admission troponin level in MICU patients when an acute coronary event is not suspected.

Intracardiac ultrasound detection of thrombus on transseptal sheath: incidence, treatment, and prevention.

BACKGROUND: Transseptal (TS) catheterization is used for left atrial (LA) ablation procedures and a major risk is thromboembolism. The purpose of this study was to assess (1) the value of intracardiac ultrasound (ICUS) monitoring during LA ablation procedures, and (2) a new technique to reduce the risk of thrombus formation. METHODS AND RESULTS: One hundred and eighty consecutive patients underwent TS catheterization under ICUS guidance with two sheaths for atrial fibrillation ablation and one for other LA procedures. Group I included the initial 90 patients in whom TS sheaths were flushed with a standard 2 U/cc concentration of heparin; group II consisted of the next 90 patients in whom sheaths were flushed with 1,000 U/cc concentration. All patients received bolus and infusion of heparin to maintain ACT between 250-300 seconds. ICUS was monitored throughout. In group I, echodense material at the tip of the sheath consistent with thrombus was observed on ICUS in 8 of 90 patients (9%) within 5-15 minutes of entering the LA. In group II, only 1 of 90 patient (1%) demonstrated thrombus (P < 0.001). There were no significant clinical differences in group I patients with and without thrombus. In all nine patients, the clot was removed with vigorous aspiration. No patients suffered a neurological event. CONCLUSION: Thrombus formation on TS sheath, detected by ICUS, may be more common than expected despite adequate anticoagulation. Using a higher concentration of heparin for the TS system before deployment reduced the risk. The thrombus was retrieved with aspiration without the need to abort the procedure.