Faculty Bibliography

Warfarin is commonly used to prevent stroke in patients with atrial fibrillation; however, patients on haemodialysis may not derive the same benefit from warfarin as the general population. There are no randomized controlled studies in dialysis patients which demonstrate the efficacy of warfarin in preventing stroke. In fact, warfarin places the dialysis patient at increased risk for haemorrhagic stroke and possibly ischaemic stroke. Additionally, warfarin increases the risk of major bleeding and has been associated with vascular calcification. Routine use of warfarin in dialysis for stroke prevention should be discouraged, and therapy should only be reserved for dialysis patients at high risk for thrombo-embolic stroke and carefully monitored if implemented.

PURPOSE/OBJECTIVE:Over the last decade, there has been a significant rise in reported cases of methadone induced QT prolongation (QTP) and Torsades de Pointes (TdP) in patients treated for opioid dependence. Optimal management of these patients is challenging. METHODS:We report a case series of 12 consecutive patients admitted to our institution with methadone-induced QTP and ventricular arrhythmias. RESULTS:All patients survived the presenting arrhythmia. Successful transition to buprenorphine was accomplished in three patients. QT interval normalized and none of these patients had recurrent arrhythmias. Methadone dose was reduced in five patients with improvement of QT interval and resolution of arrhythmia. Four patients, including two with ICDs, refused or did not tolerate a reduction in their methadone dose. CONCLUSION/CONCLUSIONS:Ventricular arrhythmias in patients on methadone are an uncommon but important problem. Buprenorphine, a partial micro-opiate-receptor agonist and a kappa-opiate-receptor antagonist does not cause QTP or TdP. Buprenorphine is a useful and effective alternative to methadone in a select group of patients, including those with documented ventricular arrhythmias on methadone. Pacemakers or defibrillators should be reserved for patients who have failed buprenorphine or a reduced methadone dose.

One of the earliest antiarrhythmic drugs developed, quinidine had a significant role in the treatment of many arrhythmias. After concerns for increased risk of ventricular arrhythmia and death with quinidine emerged, the use of quinidine fell dramatically in favor of newer antiarrhythmic medications. However, recent trials have generated renewed interest in the use of quinidine. In particular, quinidine appears to be safe and efficacious in combination with verapamil for the treatment of atrial fibrillation. Quinidine has also been used successfully to treat idiopathic ventricular fibrillation, Brugada syndrome, and Short QT syndrome. Although it is one of the oldest drugs in our armamentarium, quinidine continues to have a role in modern cardiology.

BACKGROUND:Although prophylactic implantable cardioverter-defibrillator (ICD) implantation is beneficial in patients with severe ischemic cardiomyopathy, it is unclear whether patients with cardiomyopathy due to valvular heart disease have a similar benefit. METHODS:We followed 17 patients (14 men/three women, age 62 +/- 13 years, left ventricular ejection fraction [LVEF] 29 +/- 10%) who had nonischemic valvular cardiomyopathy, underwent valvular heart surgery (aortic valve replacement, mitral valve replacement, and/or mitral valve repair), and subsequently had an electrophysiology study (EPS), for a median of 2.8 years. These patients were compared with 34 patients with prior myocardial infarction and no significant valvular heart disease, who were matched (1:2) for age, gender, LVEF, EPS result, T-wave alternans result, and ICD placement. Occurrence of arrhythmias was ascertained from ICD device clinic follow-up and vital status was determined using the National Death Index. RESULTS:There were no differences between the groups in overall survival (P = 0.24) or arrhythmia-free survival (P = 0.38), and the 2-year arrhythmia-free survival was 82% for the valvular patients versus 73% for the ischemic patients. Among patients with ICDs, there was no difference between the groups in overall survival (P = 0.34), time to first appropriate ICD therapy (P = 0.54), and arrhythmia-free survival (P = 0.51). CONCLUSION/CONCLUSIONS:Patients with valvular cardiomyopathy and residual left ventricular dysfunction following valvular surgery who underwent a tailored approach to ICD implantation had similar overall and arrhythmia-free survival as patients with ischemic cardiomyopathy.

INTRODUCTION/BACKGROUND:Female gender has been associated with worse clinical outcomes following coronary revascularization. Whether a gender-specific difference in vessel size is contributing to this finding remains controversial. We sought to better define the relationship between gender and coronary artery size. METHODS:Baseline characteristics were obtained and quantitative coronary angiography was performed on 145 consecutive patients with angiographically normal (smooth luminal surface with no evidence of any irregularity in the coronary tree) coronary arteries. Two separate orthogonal measurements each were taken of the left main, proximal left anterior descending, proximal circumflex, proximal right coronary artery, and ostial posterior descending arteries. An average coronary size, derived from five separate coronary artery measurements, was tabulated for each patient. RESULTS:After correcting for confounding variables, including BSA, height, diabetes, and left ventricular hypertrophy using multivariate linear regression, female gender remained a strong independent predictor of coronary vessel size (Beta =-0.30, P = 0.004). Female gender was associated with a 0.30 mm decrease in average coronary size. CONCLUSION/CONCLUSIONS:Gender is a strong, independent predictor of coronary artery size even when taking into account differences in body size. This difference may contribute to worse outcomes of women undergoing coronary revascularization.