Ahmed Aziz

Radiofrequency Catheter Ablation of Type 1 Atrial Flutter Prediction of Late Success by Electrophysiological Criteria

BACKGROUND Radiofrequency energy has demonstrated its efficacy in catheter ablation of atrial flutter (AFl). However, long-term recurrences of AFl have been reported frequently after initial, apparently successful ablation. To date, criteria for prediction of late recurrences are lacking. METHODS AND RESULTS Twelve patients (10 men; mean age, 53.6 years; range, 26 to 69 years) were referred for AFl ablation. Duodecapolar and decapolar catheters were used for detailed mapping of the tricuspid ring, the inferior vena cavatricuspid annulus (IVC-TA) isthmus, and the coronary sinus ostium (CSOs) area. Additional multipolar catheters were used for recording activation of the coronary sinus and the CSOs-TA isthmus. AFl was present at baseline in 9 patients and was induced by proximal coronary sinus (PCS) pacing in 3. Counterclockwise right atrial activation was recorded in all patients. Primary success of ablation was defined as when AFl was no longer inducible even during isoproterenol infusion. AFl was successfully ablated in all 12 patients, with a median of 4 pulses delivered at the IVC-TA isthmus. In the 3 patients in whom AFl was induced, during PCS pacing in sinus rhythm before ablation, a collision of descending and ascending wave fronts was observed at the middle lateral right atrium (LRA). This activation pattern of the LRA also was noted after unsuccessful radiofrequency applications. Noninducibility of AFl after radiofrequency applications was associated with a change of activation pattern at the LRA and with an inversion of the activation sequence of the IVC-TA isthmus (from clockwise to counterclockwise) in 9 patients when pacing from the PCS. In 2 of 3 patients, despite noninducibility of atrial flutter, ablation was pursued to obtain evidence of permanent block of conduction at the IVC-TA isthmus. Finally, a completely descending LRA wave front was observed when pacing from the PCS in all patients except one. Low LRA pacing was also performed in 4 patients and showed evidence for block in the counterclockwise direction at the isthmus. During a follow-up of 9 +/- 3 months, AFl recurred in 1 patient; this was the only patient who showed no conduction block at the isthmus after the procedure. CONCLUSIONS Direction of impulse propagation at LRA and block of propagation at the IVC-TA isthmus during PCS and low LRA pacing appear to be of interest in predicting long-term success of AFl ablation.

Discrepancy between coronary artery calcium score and HeartScore in middle-aged Danes: the DanRisk study

Background: Coronary artery calcification (CAC) is an independent and incremental risk marker. This marker has previously not been compared to the HeartScore risk model. Design: A random sample of 1825 citizens (men and women, 50 or 60 years of age) was invited for screening. Methods: Using the HeartScore model, the 10-year risk of fatal cardiovascular events based on gender, age, smoking, systolic blood pressure, and total cholesterol was estimated. A low risk was defined as <5%. The CAC score was calculated from a non-contrast enhanced cardiac-CT scan and given in Agatston U. Results: A total of 1257 (69%) of the invited subjects were interested in the screening. Due to previous cardiovascular disease or diabetes mellitus, 101 were excluded. Of the remaining 1156, 47% were men and 53% women; one half were 50 years old and the other half 60 years old. A low HeartScore was found in 901 of which 334 (37%) had CAC. A high HeartScore was recorded in 251 of which 80 (32%) did not have any CAC. High HeartScores and CAC were significantly more common in males than females. Conclusions: CAC is common in healthy middle-aged Danes with a low HeartScore, and, on the contrary, high-risk subjects very frequently do not have CAC. The therapeutic and prognostic implications of these observations remain to be clarified.

Coronary Microvascular Function and Cardiovascular Risk Factors in Women With Angina Pectoris and No Obstructive Coronary Artery Disease: The iPOWER Study

Background The majority of women with angina‐like chest pain have no obstructive coronary artery disease when evaluated with coronary angiography. Coronary microvascular dysfunction is a possible explanation and associated with a poor prognosis. This study evaluated the prevalence of coronary microvascular dysfunction and the association with symptoms, cardiovascular risk factors, psychosocial factors, and results from diagnostic stress testing. Methods and Results After screening 3568 women, 963 women with angina‐like chest pain and a diagnostic coronary angiogram without significant coronary artery stenosis (<50%) were consecutively included. Mean age (SD) was 62.1 (9.7). Assessment included demographic and clinical data, blood samples, questionnaires, and transthoracic echocardiography during rest and high‐dose dipyridamole (0.84 mg/kg) with measurement of coronary flow velocity reserve (CFVR) by Doppler examination of the left anterior descending coronary artery. CFVR was successfully measured in 919 (95%) women. Median (IQR) CFVR was 2.33 (1.98–2.76), and 241 (26%) had markedly impaired CFVR (<2). In multivariable regression analysis, predictors of impaired CFVR were age (P<0.01), hypertension (P=0.02), current smoking (P<0.01), elevated heart rate (P<0.01), and low high‐density lipoprotein cholesterol (P=0.02), but these variables explained only a little of the CFVR variation (r 2=0.09). CFVR was not associated with chest pain characteristics or results from diagnostic stress testing. Conclusion Impaired CFVR was detected in a substantial proportion, which suggests that coronary microvascular dysfunction plays a role in the development of angina pectoris. CFVR was associated with few cardiovascular risk factors, suggesting that CFVR is an independent parameter in the risk evaluation of these women. Symptom characteristics and results from stress testing did not identify individuals with impaired CFVR.

Improving diagnosis and treatment of women with angina pectoris and microvascular disease: The iPOWER study design and rationale

BACKGROUND The iPOWER study aims at determining whether routine assessment of coronary microvascular dysfunction (CMD) in women with angina and no obstructive coronary artery disease is feasible and identifies women at risk. METHODS All women with angina referred to invasive angiographic assessment in Eastern Denmark are invited to join the study according to in- and exclusion criteria. Assessment includes demographic, clinical and psychosocial data, symptoms, electrocardiogram, blood- and urine samples and transthoracic echocardiography during rest and dipyridamol stress with measurement of coronary flow reserve (CFR) by Doppler of the left anterior descending artery. In substudies CMD will be assessed by positron emission tomography, peripheral endothelial function, magnetic resonance imaging-and computed tomography derived myocardial perfusion scans, angiographic corrected TIMI frame counts, advanced echocardiographic modalities at rest and during stress, and invasive measures of CFR and coronary vascular reactivity. The study will include 2000 women who will be followed for 5 years for cardiovascular outcomes. RESULTS By May 2013, 1685 women have been screened, 759 eligible patients identified, 530 contacted, and 299 (56%) agreed to participate. Among the first 50 patients, Doppler CFR was successfully measured in 49 (98%). CONCLUSIONS Among women with suspected ischemic heart disease and no obstructive coronary artery disease, non-invasive Doppler CFR is feasible as a routine assessment. The study will provide information on methods to diagnose CMD and determine the prognostic value of routine non-invasive assessment of microvascular function. Future study will provide women identified with CMD participation in interventional substudies designed to test treatment strategies.

Structural and Functional Coronary Artery Abnormalities in Patients With Vasospastic Angina Pectoris

Coronary spasm is involved in many clinical scenarios, such as stable angina, acute coronary syndrome, sudden cardiac death, non-ischemic cardiomyopathy, arrhythmia and syncope. In recent years, imaging tools such as computerized tomographic angiography, intravascular ultrasound or optical coherence tomography have been applied to study the coronary pathology in patients with vasospastic angina. Patients with vasospastic angina represent a heterogeneous cohort of patients with regard to the extent of concomitant coronary atherosclerosis. They share the common pathophysiological phenomenon of vascular smooth muscle hyperreactivity leading to spasm caused by various factors that may also overlap. Focal coronary spasm is related to epicardial atherosclerosis and in the presence of obstructive coronary artery disease it may be useful to treat the lesion to prevent further spasm. The aim of this article is to review structural and functional coronary artery abnormalities in patients with vasospastic angina.

Clinical characteristics, myocardial perfusion deficits, and clinical outcomes of patients with non-specific chest pain hospitalized for suspected acute coronary syndrome: A 4-year prospective cohort study

BACKGROUND Although the prognostic role of stress SPECT MPI is generally well established, its value in predicting non-fatal cardiac events in patients with acute, non-specific chest pain (NSCP) remains unclear. The aims of this study are 1) to describe the baseline clinical characteristics and prevalence of myocardial perfusion (MP) deficits, by use of an adenosine stress SPECT MPI, in NSCP patients without known CAD discharged after hospitalization for suspected ACS; and 2) to prospectively describe the 4-year clinical outcome in terms of all-cause and cardiac mortality; hospitalization and coronary revascularization procedures; and cardio-vascular events in patients with and without MP deficits. METHODS AND RESULTS We evaluated a series of 272 consecutive patients with acute NSCP and aged 18-75years. ICD10-based registries were used to determine the primary outcome (a composite measure of incident CAD death, ACS, or revascularization) and two secondary outcomes (1. all-cause death; 2. a composite measure of cardiovascular death, ACS, revascularization, or stroke). Forty two (15%) participants had a MP deficit. During follow-up (median 1361days), 7 participants had a primary event, 4 died, and 20 had a secondary composite event. Annual event rates were 0.70, 0.39 and 2.07, respectively. MP deficits predicted both subsequent primary and composite secondary events (HR: 7.54; 95% CI=[1.69; 33.69] and 2.93 (95% CI=[1.10; 7.81], respectively). Usual clinical cardiac risk classification could not meaningfully differentiate between patients with and without MP deficits. CONCLUSION SPECT MPI substantially improved prediction of incident CAD beyond usual clinical procedures and risk classification systems among NSCP patients.