Underutilization of implantable cardioverter defibrillators post coronary artery bypass grafting in patients with systolic dysfunction.

BACKGROUND: Evaluation of the need for prophylactic internal cardiac defibrillators among patients with ischemic cardiomyopathies should be deferred until at least 3 months after revascularization procedures to allow adequate time for recovery of ventricular function. METHODS: Among patients with left ventricular systolic dysfunction (LVSD) who undergo coronary artery bypass grafting (CABG), the proportion of patients who are risk stratified postoperatively with reassessment of left ventricular ejection fraction (LVEF) is unknown. RESULTS: One hundred and six patients with LVSD (LVEF < 40%) who underwent CABG during 2004-2006 and survived 3 months post CABG were evaluated. Follow-up was assessed by chart review and telephone contact. LVEF was not reassessed in 24% (25/106) of the population, none of whom underwent internal cardioverter defibrillator (ICD) implantation. Of those with LVEF reassessed, persistent LVSD was present in 20/81 (25%), 12 of whom were referred for prophylactic ICD placement. CONCLUSION: One-fourth of patients with LVSD who undergo CABG do not have LVEF reassessed postoperatively which may lead to underutilization of ICDs.

Stress cardiomyopathy (takotsubo cardiomyopathy).

BACKGROUND: Due to the rise in the number of reports of stress cardiomyopathy in the literature, awareness of this condition is increasing. Although different names have been used to describe this condition, the similarities in clinical, electrocardiographic, echocardiographic, and angiographic features suggest that they represent the same spectrum of diseases with different underlying causes. The pathophysiology of stress cardiomyopathy remains controversial. METHODS: We describe a series of four cases of stress cardiomyopathy admitted to our institution over a period of six months with different presentations, but similar clinical course, EKG, echocardiographic, and catheterization findings. The ages ranged from 22 to 81 years; all four females. All showed characteristic wall motion abnormalities by imaging in the absence of significant coronary artery disease, with spontaneous recovery of left ventricular function with conservative therapy. RESULTS: Although the patients presented with different clinical scenarios, all four showed characteristic features of stress cardiomyopathy suggesting that the pathophysiology affecting the myocardium was the same. We present a review of the literature with a discussion of the history of this condition, characteristic clinical features, and diagnostic criteria used in the past as well as the suggested pathophysiology of this condition. CONCLUSION: Stress cardiomyopathy is an underdiagnosed reversible cardiomyopathy triggered by severe emotional or physical stress. It represents a spectrum of conditions with reversible severe left ventricular systolic dysfunction that includes neurogenic cardiomyopathy. It is not confined to the Japanese population and can affect people of any ethnic background or nationality.

Dual chamber pacing in a patient of hypertrophic cardiomyopathy with failure to wean from mechanical ventilator.

We discuss the case of a 63 years old female who required repeated intubation due to recurrent pulmonary edema. She was found to have hypertrophic cardiomyopathy with a gradient of 82 mmHg across the left ventricular outflow tract. Initially adequate rate control and treatment with negative inotropes did not help her condition. Finally a dual chamber pacemaker implantation and atrioventricular node modification lead to successful extubation.

Troponin elevation in patients with various tachycardias and normal epicardial coronaries.

Troponin elevation is usually synonymous with acute coronary syndrome (ACS). Although sensitive for ACS, the elevation of serum troponin, in the absence of clinical evidence of ischemia, should prompt a search for other etiologies of myocardial necrosis. In fact, elevated values of troponin are correlated with myocardial necrosis even though it does not discriminate the mechanism involved. We report a series of seven patients (age range 18-67 years), who presented with complaints of chest discomfort and were found to have regular supraventricular tachycardia (5 patients) and one patient each with atrial fibrillation and ventricular tachycardia. All these patients had elevated troponin I and underwent coronary angiography that revealed normal epicardial coronary arteries. This is first case series in which all patients underwent coronary angiography and none of the patients was hemodynamically unstable at the time of presentation. Patients with elevated troponin due to conditions other than ACS can receive inappropriate and delayed definitive diagnosis and treatment.

Persistent left superior vena cava: a blessing in disguise.

Persistent left superior vena cava (SVC) is an uncommon condition, usually encountered during cannulation of the left subclavian vein. We describe a patient who required a cardiac device upgrade to cardiac resynchronization implantable cardioverter defibrillator for biventricular failure. The presence of a persistent left SVC proved to be a blessing in disguise in this patient as he had since developed total occlusion of the left subclavian-innominate system.

Atrial fibrillation: current concepts.

Atrial fibrillation (AF) is the most common arrhythmia which is a focus of newer modalities of treatment, especially ablation techniques using innovative mapping techniques. Its incidence and prevalence increases with aging and presence of structural heart disease, the latter being less than 1% prior to age 40, rising to 8% at age 80. Concomittant morbidity and excessive mortality is related to the increased incidence of stroke and congestive heart failure. Once developed in a clinical setting, it tends to either persist or recur. Pharmacotherapy to control rate or rhythm tends to have a secondary failure, and therefore there is a growing interest in ablation techniques. The use of anticoagulation is also associated with bleeding risks and therefore the management of AF needs to be individualized in every patient. In this article, we shall be discussing clinical types of AF, etiology, the mechanism of genesis, symptoms, complications and approach to treatment in various clinical scenarios.

Deglutition induced atrial tachycardia and atrial fibrillation.

Deglutition induced supraventricular tachycardia is an uncommon condition postulated to be a vagally mediated phenomenon due to mechanical stimulation. Patients usually present with mild symptoms or may have severe debilitating symptoms. Treatment with Class I agents, beta blockers, calcium channel blockers, amiodarone and radiofrquency catheter ablation has shown to be successful in the majority of reported cases. We report the case of a 46-year-old healthy woman presenting with palpitations on swallowing that was documented to be transient atrial tachycardia with aberrant ventricular conduction as well as transient atrial fibrillation. She was successfully treated with propafenone with no induction of swallowing-induced tachycardia after treatment. This is also the first case to show swallowing-induced atrial tachycardia and atrial fibrillation in the same patient.

Piggy-back pacing: implantation of pacemaker and defibrillator on top of each other.

Following the publication of several landmark trials, there has been a significant increase in the cardiac device implantation. Within this population there are a number of patients who have pre-existing cardiac devices that have been placed for a number of different conditions. While the usual approach is to remove the existing unit and replace it with a new device with the removal or capping of existing lead systems, this practice often sacrifices an existing unit that still possesses good battery longevity. We explored the possibility of separating the pacing and defibrillating functions by implanting a new device on the top of the old device in a 'piggy-back fashion'. We report a series of four cases (with various indications) with differing combinations of devices. The procedure was performed safely in every one of them, and no device-device interaction was noted. Combining the new with existing units in a 'piggy-back' manner may be a safe and cost-effective technique in the selected cases.