Biomedical subjects

Francis E Marchlinski

Publications and source records attributed to Francis E Marchlinski.

57 records · Page 4Linked to original sources

PubMed2002

Intracardiac Doppler echocardiographic quantification of pulmonary vein flow velocity: an effective technique for monitoring pulmonary vein ostia narrowing during focal atrial fibrillation ablation.

INTRODUCTION: Ablation at the pulmonary vein (PV) ostium to isolate triggers for atrial fibrillation (AF) may induce PV narrowing. The AcuNav ultrasound catheter can image PV flow and quantify peak velocity and may be useful in assessing the degree of narrowing of PV ostia. METHODS AND RESULTS: In 93 patients with AF undergoing PV ostial ablation (up to 40 W, 52 degrees C, 90 sec), the ultrasound catheter was placed in the right atrium and PV peak flow velocities were measured during systole and diastole before and after ablation. Ostial PV electrical isolation was achieved in 216 of the 219 targeted PVs. The ultrasound catheter provided flow imaging of all PVs. The ostial peak flow velocities measured 56 +/- 12 cm/sec before ablation and increased to 101 +/- 22 cm/sec after ablation (P < 0.001). Peak velocity >100 cm/sec was detected in 103 (47%) of 219 and > or = 158 cm/sec (estimated pressure gradient 10 mmHg) with turbulent flow features, in 7 (3.2%) of 219 PVs. The highest velocity detected in one PV was 211 cm/sec (17.7 mmHg). Follow-up ultrasound catheter measurements were obtained in 13 patients (30 previously ablated PVs) during repeat ablations. The ostial peak velocity had decreased by 22 +/- 14 cm/sec and in 25 (83%) of 30 PVs was within the baseline range (<100 cm/sec) at a mean follow-up of 4.9 +/- 2.2 months. Follow-up magnetic resonance imaging (MRI) or contrast-enhanced CT was obtained at 7.0 +/- 3.8 months in seven patients with PV velocity > 158 cm/sec after initial ablation. No significant stenosis (<30%) was identified, and no patient suffered clinical symptoms (follow-up 6-18 months) related to the described acute changes in PV flow after an initial ablation procedure. Of 13 patients with repeat ablation, two had PV velocities >100 cm/sec before repeat ablation, and three PVs in two patients had flow velocity >158 cm/sec after repeat ablation. One of these patients developed symptoms of exertional dyspnea; MRI at 4 months showed 50% to 60% ostial narrowing. CONCLUSION: Ostial ablation for PV isolation may induce a mild-to-moderate increase in PV flow velocity, which can be identified using an ultrasound catheter with Doppler color flow imaging. Increases in PV flow velocity (<158 cm/sec) after a primary ablation procedure appear to be well tolerated, and a return toward baseline flow characteristics should be anticipated by 3 months. A more cautious approach may be required for patients undergoing repeat PV isolation.

Atrial Fibrillation↗

PubMed2002

Clinical use of AcuNav diagnostic ultrasound catheter imaging during left heart radiofrequency ablation and transcatheter closure procedures.

BACKGROUND: AcuNav ultrasound catheter (UC) (10F, 5.5-10 MHz) has unique advantages for left heart imaging with its 4-way tip flexible maneuverability, maximal 16-cm intracardiac imaging depth, and Doppler and color flow imaging capability. METHODS: We assessed the initial use of this UC in 40 consecutive patients (34 men; age 53 +/- 11 years old). All patients were also undergoing transseptal catheterization for percutaneous catheter mapping and ablation of either left atrium (focal initiated atrial arrhythmia/fibrillation, n = 32) or left ventricle (ventricular tachycardia, n = 4), or transcatheter atrial septal defect closure (n = 4) procedures. During each procedure, the UC was placed in the right atrium, superior vena cava, or right ventricular inflow/outflow tract. RESULTS: In all patients, UC successfully guided transseptal catheterization and provided imaging of normal or aberrant anatomy of the right/left atrial (interatrial septum, fossa ovalis, appendages, 4 pulmonary vein ostia) and right/left ventricular (valves and papillary muscles) structures. UC was important in early identification procedure complications, including pericardial effusion (n = 2, detected before systematic hemodynamic deterioration) and thrombus formation on sheaths deployed in the right atrium (n = 9) and left atrium (n = 2, early elimination with management of the sheath). With Doppler and color flow imaging, UC provided effective monitoring of increased flow velocity of all ablated pulmonary vein ostia and detection of patent foramen ovale (n = 6) or residual trivial/small atrial septal defect posttransseptal catheterization (n = 2). UC was also used to successfully image and guide transcatheter closure of atrial septal defect with positioning of the cardioseal septal occluder (Nitinol Medical Technologies Inc, Boston, Mass) and color Doppler imaging of no significant residual shunt. CONCLUSION: AcuNav UC with Doppler and color flow imaging has significant use, especially during left heart ablation. Uses include guidance of transseptal and mapping/ablation catheters and closure devices, and prompt diagnosis of cardiac complications.

Adult↗

PubMed2000

Debate: Do all patients with heart failure require implantable defibrillators to prevent sudden death?

Sudden death is a major cause of mortality in patients with ventricular dysfunction. The highest risk occurs among patients with less severe functional impairment. Current methods of risk stratification are inadequate, and a rational therapy for prevention of sudden death is not available. The implantable cardioverter-defibrillator (ICD) has proven to be more effective than drugs in reducing sudden-death risk in some subsets of patients. Empiric ICD therapy, targeting the general population with mild to moderate heart failure, will maximize the impact of such a strategy to prevent sudden death and improve long-term survival.

Journal Article↗