Limitations in the current screening practice of assessing left ventricular ejection fraction for a primary prophylactic implantable defibrillator in southern Ontario.

BACKGROUND: Screening echocardiography (ECHO) is commonly performed to determine whether the patient's left ventricular ejection fraction (LVEF) is appropriate for primary prophylactic implantable cardiac defibrillator (ICD) referral. However, radionuclide ventriculography (RNA) is used by many implantation centres for decision making. OBJECTIVE: To determine whether current screening ECHO techniques are effective in identifying patients suitable for primary prophylactic ICD referral. METHODS: Correlation, sensitivity, specificity and likelihood ratios (LRs) of semiquantitative and numerical quantitative ECHO LVEFs were calculated for predicting RNA LVEFs that met implantation criteria (LVEF less than 30% and less than 35%). RESULTS AND DISCUSSION: Among 193 patients, the LRs for a semiquantitative ECHO predicting an RNA LVEF of less than 30% (negative LR was 0.21 to 0.69 and positive LR was 1.22 to 2.83) or RNA LVEF of less than 35% (negative LR was 0.24 to 0.73 and positive LR was 1.33 to 3.46) demonstrated that current screening ECHO techniques are ineffective. However, the positive predictive value of grade 4 ECHO was 93.0%, suggesting that these patients may not require further LVEF investigation before implantation. Among 102 patients, current quantitative ECHO techniques did not improve the screening characteristics. CONCLUSIONS: Current screening ECHO techniques may not be adequate for screening patients for consideration of a primary prophylactic ICD, but a grade 4 ECHO finding has a high positive predictive value in meeting implantation LVEF criteria. Improved screening standards should increase the number of patients referred with appropriate LVEF for primary prophylactic ICD implantation.

An unusual case of chronic coronary artery dissection: did cisplatin play a role?

Spontaneous coronary artery dissection is an unusual cause of acute myocardial ischemia. The natural history of spontaneous coronary artery dissection that persists on angiography after the acute event has not been well characterized. A case of a 36-year-old man who presented with monomorphic ventricular tachycardia 12 years following a myocardial infarction that occurred during his last course of bleomycin-etoposide-cisplatin therapy for testicular cancer is reported. On further investigation, coronary angiography revealed a long chronic dissection of the right coronary artery. The patient was successfully treated with medical management and insertion of an implantable cardioverter defibrillator. The case also highlights the increased cardiovascular morbidity in testicular cancer survivors and evokes the possibility of mechanisms of myocardial ischemia other than atherosclerotic disease in these young patients.

Long-term comparison of the implantable cardioverter defibrillator versus amiodarone: eleven-year follow-up of a subset of patients in the Canadian Implantable Defibrillator Study (CIDS).

BACKGROUND: The implantable cardioverter defibrillator (ICD) is superior to amiodarone for secondary prophylaxis of sudden cardiac death. However, the magnitude of this benefit over long-term follow-up is not known. Thus, our objective was to evaluate the long-term consequences of using amiodarone versus an ICD as first-line monotherapy in patients with a prior history of sustained ventricular tachycardia/ventricular fibrillation or cardiac arrest. METHODS AND RESULTS: A total of 120 patients were enrolled at St Michael's Hospital in the Canadian Implantable Defibrillator Study (CIDS) and were randomly assigned to receive either amiodarone (n=60) or an ICD (n=60). The treatment strategy was not altered after the end of CIDS unless the initial assigned therapy was not effective or was associated with serious side effects. After a mean follow-up of 5.6+/-2.6 years, there were 28 deaths (47%) in the amiodarone group, compared with 16 deaths (27%) in the ICD group (P=0.0213). Total mortality was 5.5% per year in the amiodarone group versus 2.8% per year in the ICD group (hazard ratio of amiodarone: ICD, 2.011; 95% confidence interval, 1.087 to 3.721; P=0.0261). In the amiodarone group, 49 patients (82% of all patients) had side effects related to amiodarone, of which 30 patients (50% of all patients) required discontinuation or dose reduction; 19 patients crossed over to ICD because of amiodarone failure (n=7) or side effects (n=12). CONCLUSIONS: In a subset of CIDS, the benefit of the ICD over amiodarone increases with time; most amiodarone-treated patients eventually develop side effects, have arrhythmia recurrences, or die.