Alborz Hassankhani

Correlation of left ventricular diastolic filling characteristics with right ventricular overload and pulmonary artery pressure in chronic thromboembolic pulmonary hypertension.

OBJECTIVES This study was designed to determine a quantitative relationship between right ventricular (RV) pressure overload and left ventricular (LV) diastolic filling characteristics in patients with chronic thromboembolic pulmonary hypertension (CTEPH). BACKGROUND Right ventricular pressure overload in patients with CTEPH causes abnormal LV diastolic filling. However, a quantitative relationship between RV pressure overload and LV diastolic function has not been established. METHODS We analyzed pre- and postoperative diastolic mitral inflow velocities and right heart hemodynamic data in 39 consecutive patients with CTEPH over the age of 30 (55 +/- 11 years) with mean pulmonary artery pressure >30 mm Hg who underwent pulmonary thromboendarterectomy (PTE). RESULTS After PTE, mean pulmonary artery pressure (mPAP) decreased from 50 +/- 11 to 28 +/- 9 mm Hg (p < 0.001) while cardiac output (CO) increased from 4.4 +/- 1.1 to 5.7 +/- 0.9 l/m (p < 0.001). Mitral E/A ratio (E/A) increased from 0.74 +/- 0.22 to 1.48 +/- 0.69 (p < 0.001). E/A was < 1.25 in all patients pre-PTE. After PTE, all patients with E/A >1.50 had mPAP <35 mm Hg and CO >5.0 l/min. E/A correlated inversely with mPAP (r = 0.55, p < 0.001) and directly with CO (r = 0.53, p < 0.001). CONCLUSIONS E/A is consistently abnormal in patients with CTEPH and increases post-PTE. Moreover, E/A varies inversely with mPAP and directly with CO. Following PTE, E/A >1.5 correlates with the absence of severe pulmonary hypertension (mPAP >35 mm Hg) and the presence of normal cardiac output (> 5.0 l/m).

Abnormal Heart Rate Turbulence Predicts the Initiation of Ventricular Arrhythmias

Background: Abnormal heart rate turbulence (HRT) reflects autonomic derangements predicting all‐cause mortality, yet has not been shown to predict ventricular arrhythmias in at‐risk patients. We hypothesized that HRT at programmed ventricular stimulation (PVS) would predict arrhythmia initiation in patients with left ventricular dysfunction.

Conduction Velocity Around the Tricuspid Valve Annulus During Type 1 Atrial Flutter: Defining the Location of Areas of Slow Conduction by Three-Dimensional Electroanatomical Mapping

AbstractBackground: Conduction velocity (CV) around the tricuspid valve annulus (TVA) during type 1 atrial flutter (AFL) has been shown to be slowest in the tricuspid valve-inferior vena cava (TV-IVC) isthmus, compared to the septal or free wall segments of the TVA. However, fiber orientation in the triangle-of-Koch suggests that the inferior septum and medial TV -IVC isthmus should be the most slowly conducting segments around the TVA. Methods: To test this hypothesis we evaluated CV around the TVA during type 1 atrial flutter in 11 patients, using an electro-anatomical mapping system (Carto™). CV was first calculated in 4 segments around the TVA including the TV-IVC isthmus, lateral free wall, superior free wall and septum, and then calculated in 8 segments around the TVA including medial (MI) and lateral isthmus (LI), inferior (IL) and superior lateral (SL) free wall, lateral (LS) and medial superior (MS) free wall, and superior (SS) and inferior septum (IS). Statistical comparison of CV from these multiple segments was made by one-way analysis of variance. Results: Measured in 4 segments around the TVA, mean CV (m/sec) in the TV-IVC isthmus (0.81 ± 0.23) and the septum (0.93 ± 0.18) was significantly slower than CV in the lateral free wall (1.16 ± 0.23) and superior free wall (1.10 ± 0.20), and CV in the TV-IVC isthmus was significantly slower than in the septum (p < 0.05). However, when analyzed in 8 segments, mean CV in the MI (0.56 ± 0.16) and IS (0.59 ± 0.24) was significantly (p < 0.05) slower than in all other segments including the LI (1.06 ± 0.46), IL (1.17 ± 0.40), SL (1.15 ± 0.40), LS (1.04 ± 0.25), MS (1.15 ± 0.28), and SS (1.26 ± 0.36) segments. Conclusions: Consistent with previous reports, CV around the TVA during type 1 AFL was slowest in the TV-IVC isthmus, compared to the septum, superior and lateral free wall regions. However, when the TVA was further subdivided into 8 segments, CV in the MI and IS segments was significantly slower than in all other segments around the TVA. These observations more precisely define the regions of slow conduction in human type 1 AFL, and are consistent with the known anisotropy and slow conduction in the Triangle of Koch.

Quantifying Intracardiac Organization of Atrial Arrhythmias Using Temporospatial Phase of the Electrocardiogram

Introduction: Separating nonisthmus‐dependent atrial flutter (AFL) from “organized” atrial fibrillation (AF), or isthmus‐dependent AFL, may be difficult using ECG characteristics alone. We hypothesized that temporal and spatial phase analysis of ECG atrial waveforms could effectively separate these rhythms by quantifying subtle variations in ECG atrial activation during supraventricular tachycardias (SVT).

Imaging of Intracoronary Thrombus by Multidetector Helical Computed Tomography Angiography

An 83-year-old woman presented to the emergency department with a 2-hour history of sudden chest pain and dyspnea. An initial ECG demonstrated nonspecific ST changes, and a portable chest x-ray suggested a widened mediastinum. A thoracic multidetector helical computed tomography (CT) angiogram was obtained to assess the possibility of aortic dissection (GE LightSpeed Plus, 2.5-mm collimation with 1.25-mm reconstructions, 700-ms rotation time; 140 mL Optiray 320 nonionic iodinated contrast …

Relationship Between the Heparin Management Test and the HemoTec Activated Clotting Time in Patients Undergoing Percutaneous Coronary Intervention

Point-of-care whole blood coagulation tests are critical in the management of patients who undergo percutaneous coronary intervention. The Hemochron and HemoTec devices have been traditionally used to measure the activated clotting time (ACT) in the cardiac catheterization laboratory. The heparin management test (HMT) was recently introduced into clinical practice as an alternative method to current ACT measurements that uses a different sample volume, contact activators and detection system to measure whole blood coagulation. We compared the HMT to the HemoTec ACT in 68 prospectively enrolled patients (127 blood samples) undergoing percutaneous coronary intervention. Measurements were performed 10 minutes after the initial heparin bolus and thereafter at the discretion of the attending physician. The mean HMT was 41 seconds higher (∼15%) than the HemoTec ACT (HMT 304±59 vs. ACT 263±52, P< 0.0001), but there was a significant correlation between the methods (r=0.77, P<0.0001). However, there was increasing disagreement between the two methods as the level of anticoagulation increased. The relationship between HMT and ACT was similar in patients in whom glycoprotein IIb/IIIa inhibitors were used. The HMT, therefore, appears to be more sensitive to heparin anticoagulation that the HemoTec ACT and correlates well with it in the range required for percutaneous coronary intervention.