Clinical significance of cardiomegaly caused by cardiac adiposity.

Enlarged cardiac silhouette on chest x-ray (CXR) in the absence of cardiopulmonary disease is often dismissed as "pseudocardiomegaly." We aimed to assess the impact of epicardial adipose tissue (EAT) on radiographic heart size and to determine the clinical significance of cardiomegaly caused by EAT. In total 112 patients (52 ± 13 years old, 53% women, body mass index 32 ± 8 kg/m(2)) with structurally normal hearts by transthoracic echocardiography underwent cardiac computed tomography (CCT). EAT volume was measured by CCT and cardiothoracic ratio (CTR) and cardiac transverse and lateral horizontal transverse diameters were measured on posteroanterior and lateral view CXR. EAT volume (mean 122 ± 49 ml) correlated directly with age, body mass index, hypertension, hyperlipidemia (p <0.05 for all comparisons), transverse diameter (r = 0.50, p <0.001), CTR (r = 0.45, p <0.001), and lateral horizontal transverse diameter (r = 0.38, p <0.001). EAT volume was larger in those with increased (n = 22) compared to those with normal (n = 90) CTR (154 ± 54 vs 115 ± 54 ml, p = 0.0005). Patients with cardiomegaly were also older (58 ± 13 vs 50 ± 12 years old, p = 0.009) and more often had diabetes (32% vs 9%, p = 0.03), hypertension (86% vs 46%, p = 0.001), hyperlipidemia (68% vs 44%, p = 0.04), or obstructive coronary artery disease by CCT (32% vs 11%, p = 0.04). Coronary artery calcium score was also higher in those with cardiomegaly (median 56 [first tertile 0, third tertile 298] vs 0 [0, 55], p = 0.006). In conclusion, cardiomegaly on CXR can be caused by excessive EAT. This is associated with several coronary risk factors and with coronary calcification and stenosis. Cardiomegaly in this setting may be regarded as another noninvasive marker of coronary atherosclerosis.

Safety of adenosine pharmacologic stress myocardial perfusion imaging in orthotopic cardiac transplant recipients: a single center experience of 102 transplant patients.

Denervation super-sensitivity to adenosine is well described in cardiac transplant (CT) patients particularly early after transplant. The safety and hemodynamic effects of adenosine SPECT (A-SPECT) has not been described in a large series of CT patients. Single center retrospective study of 102 CT patients undergoing A-SPECT were compared to an age-gender matched patients in a 2:1 fashion who underwent A-SPECT in the same time period. Multivariate logistic regression model were used to identify independent predictors of advanced AV block. The average time from CT to A-SPECT was 8.5 ± 4.5 years. Average age was 57 years with 80% males. In comparison to the control group, adenosine infusion was associated with a higher incidence of sinus pause (4.9% vs. 0%), 2nd (11.8% vs. 4.9%) and 3rd degree AVB (2.9% vs. 0%) in CT patients (all P < 0.05). Prior use of aspirin and baseline 1st degree AVB were significant independent predictors of adenosine induced AVB. Baseline right or left bundle branch block, beta-blockers, calcium blockers or digoxin were not associated with occurrence of AVB. Only 1.9% of A-SPECT studies were terminated due to bradyarrythmia with 1 patient requiring aminophylline. There were no significant immediate or long term adverse events in these patients. Adenosine pharmacologic stress is associated with a higher incidence of AVB and sinus pause in CT patients reflecting persistence of super sensitivity late after CT. Nevertheless these bradyarrythmias are transient without any sequelae suggesting that A-SPECT can be performed safely in CT patients.

Transient global amnesia after ablation of premature ventricular beats arising from the right coronary cusp.

A 58-year-old female underwent PVC ablation within the right coronary cusp for symptomatic PVCs and suspected PVC-induced cardiomyopathy. Immediately after the procedure, she started to complain about feelings of impending doom, disorientation to time and place, and amnesia regarding the procedure. No sensory or motor deficits could be elicited. A thromboembolic event was suspected and she was evaluated by a neurologist. CT scan of her brain was negative. She was diagnosed with transient global amnesia and her mentation returned to baseline within 4 hours after the procedure.

A novel approach to differentiating orthodromic reciprocating tachycardia from atrioventricular nodal reentrant tachycardia.

BACKGROUND: Various diagnostic maneuvers have been proposed to help differentiate orthodromic reciprocating tachycardia (ORT) from atrioventricular nodal reentrant tachycardia (AVNRT) prior to ablation. However, not all criteria are applicable in every situation as each has limitations. OBJECTIVE: The purpose of this study was to determine whether the behavior of tachycardia during onset of right ventricular (RV) pacing would help differentiate ORT from AVNRT. METHODS: We retrospectively reviewed 72 cases (42 typical AVNRT, 7 atypical AVNRT, 15 left free-wall pathways, 6 septal pathways, 2 right free-wall pathways). We assessed the number of beats required to accelerate the tachycardia cycle length (TCL) to the paced cycle length (PCL) once a fully RV paced complex was achieved during supraventricular tachycardia. RESULTS: In the AVNRT group, delta cycle length (DCL = PCL-TCL) was 29 +/- 16 ms compared to 29 +/- 10 ms in ORT group (P = NS). In the AVNRT group, the average number of fully RV paced beats required to reset the tachycardia was 3.7 +/- 1.1 compared to 1 +/- 0 in the ORT group (P <.0001). Using a cutoff >1 beat yielded both positive and negative predictive values of 100% for diagnosing AVNRT versus ORT. During entrainment attempts, AVNRT terminated 51% of the time and ORT terminated 65% of the time but still allowed application of the new criterion. CONCLUSION: Assessing timing and type of response of supraventricular tachycardia to RV pacing can help differentiate ORT from AVNRT with high certainty and prevent the need for other pacing maneuvers and measurements.