Is the Fascicle of Left Bundle Branch Involved in the Reentrant Circuit of Verapamil‐Sensitive Idiopathic Left Ventricular Tachycardia?

The exact reentrant circuit of the verapamil-sensitive idiopathic left VT with a RBBB configuration remains unclear. Furthermore, if the fascicle of left bundle branch is involved in the reentrant circuit has not been well studied. Forty-nine patients with verapamil-sensitive idiopathic left VT underwent electrophysiological study and RF catheter ablation. Group I included 11 patients (10 men, 1 woman; mean age 25 +/- 8 years) with left anterior fascicular block (4 patients), or left posterior fascicular block (7 patients) during sinus rhythm. Group II included 38 patients (29 men, 9 women; mean age 35 +/- 16 years) without fascicular block during sinus rhythm. Duration of QRS complex during sinus rhythm before RF catheter ablation in group I patients was significant longer than that of group II patients (104 +/- 12 vs 95 +/- 11 ms, respectively, P=0.02). Duration of QRS complex during VT was similar between group I and group II patients (141 +/- 13 vs 140 +/- 14 ms, respectively, P=0.78). Transitional zones of QRS complexes in the precordial leads during VT were similar between group I and group II patients. After ablation, the QRS duration did not prolong in group I or group II patients (104 +/- 11 vs 95 +/- 10 ms, P=0.02); fascicular block did not occur in group II patients. Duration and transitional zone of QRS complex during VT were similar between the two groups, and new fascicular block did not occur after ablation. These findings suggest the fascicle of left bundle branch may be not involved in the antegrade limb of reentry circuit in idiopathic left VT.     

Resynchronization: What if the Left Ventricular Lead Cannot Reach the Lateral or Posterolateral Wall?

Background: The recommended left ventricular (LV) lead position for cardiac resynchronization therapy (CRT) is at the lateral or posterolateral wall. However, LV leads cannot always be implanted at this site. The objective of our study was to compare the clinical response to CRT when the LV lead could be implanted or not at the lateral or posterolateral wall.
Methods: In consecutive patients implanted with a CRT device, we documented the final position achieved by the tip of the LV lead in the left anterior oblique projection. Patients were prospectively followed for 6 months after implantation. They were defined as responders if they were alive, had gained 1 New York Heart Association (NYHA) functional class, and had not been hospitalized for heart failure.
Results: The study population consisted of 77 patients (56 men, 71 ± 10 years, 62 NYHA class III, 15 NYHA class IV). The LV lead was implanted at the lateral or posterolateral wall in 54 patients (group A) and at the anterior or anterolateral wall in 23 patients (group B). At 6 months, seven patients (9%) died (all in group A). There were 37 responders (69%) in group A as compared to 22 (96%) in group B.
Conclusions: The responder rate was not inferior when the LV lead was implanted at the anterior or anterolateral wall. Thus, in case of failed implantation at the lateral or posterolateral wall, positioning the LV lead in a more anterior location appears to be a reasonable alternative. Further studies are required to confirm these findings.     

Where Are the Left Ventricular Leads Really Implanted? A Study of 90 Consecutive Patients

Background: Cardiac resynchronization therapy (CRT) is a recognized treatment for severe heart failure. The recommended left ventricular (LV) lead position is at the lateral or posterolateral wall. However, LV leads cannot always be implanted at the expected site. The aim of our study was to describe in a large series of patients the anatomical position really achieved by LV leads at implant.
Method: In consecutive patients referred for CRT, we determined the LV lead implantation success rate, the success rate for the initial target vein, and the final position achieved by the tip of the LV lead in the left and right anterior oblique projections.
Results: Ninety patients (66 men, 71 ± 9 years, 20% New York Heart Association (NYHA) class IV) were referred for an LV lead implantation between September 2003 and March 2006. A LV lead could be implanted in 92% of patients. In 70%, LV leads were implanted in the initial target vein. The final location was lateral or posterolateral in 68% and anterior or anterolateral in 32% of patients. The mean procedural time was 117 ± 42 minutes.
Conclusions: LV lead implantation was achieved in 92% of patients with mean procedure duration of less than 2 hours. Nevertheless, 30% of LV leads were implanted outside of the initial target vein and 32% at the anterior or anterolateral wall. Further studies are warranted to compare the responder rate to CRT when the LV lead is at the lateral or posterolateral wall or when the LV lead is at an alternative site.     

Transient Left Ventricular Apical Ballooning After Cocaine Use: Is Catecholamine Cardiotoxicity the Pathologic Link?

We describe a patient who developed acute chest pain after using cocaine and had ST-segment elevation in the anterior leads on electrocardiography with mild elevation of cardiac enzymes. Cardiac catheterization showed normal coronary arteries with no coronary vasospasm. Left ventricular angiography revealed typical ballooning of the left ventricular apex during systole with an estimated left ventricular ejection fraction of 25%. The symptoms improved during the next few hours, and follow-up echocardiography 4 days later showed complete resolution of the left ventricular dysfunction. Transient left ventricular apical ballooning (LVAB) was diagnosed. To our knowledge, LVAB (also known as Takotsubo cardiomyopathy or "broken heart syndrome") has not been reported previously in association with cocaine use. We discuss the possible pathophysiologic link between LVAB and cocaine-induced cardiotoxicity.     

Does Acute Volume Overloading in the Setting of Left Ventricular Dysfunction and Pulmonary Hypertension Affect the Defibrillation Threshold?

The impact of acute volume overload hemodynamics on the DFT with concurrent moderate left ventricular systolic dysfunction is unknown. Ten mongrel dogs (17.2 kg), using a crossover study design, each had baseline (study 1) hemodynamic, echocardiographic, and DFT measurements. These measurements were repeated after left ventricular dysfunction was induced using a norepinephrine (5 micrograms/kg per min) infusion (study 2). Hemodynamic and DFT parameters were obtained simulating acute heart failure by volume overload with an 0.9% normal saline infusion to an associated mean pulmonary capillary wedge pressure of > 19 mmHg (study 3). Numerous significant echocardiographic and hemodynamic parameters were noted when the animals from studies 1 and 2, 2 and 3, and 1 and 3 were compared. A significant difference in the DFT was observed only when study animals 1 and 3 were compared (P < 0.02). None of the dogs were hypoxemic at the time of the acute heart failure DFT. The mechanism of this finding remains unknown. This data would suggest that acute volume overload with associated left ventricular dysfunction does adversely affect the DFT in a canine model.     

Tissue Harmonic Imaging: A New Method for Predicting Left Ventricular Thrombus?

We report a case of spontaneous echocardiographic contrast in the left ventricle visualized by transthoracic second harmonic imaging, but not by fundamental imaging, and subsequent thrombus formation.     

Ventricular Tachycardia in Non‐Compaction of Left Ventricle: Is This a Frequent Complication?

BACKGROUND: Isolated left ventricular non-compaction is the result of incomplete myocardial morphogenesis, leading to persistence of the embryonic myocardium. The condition is recognized by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricle. Whether these intertrabecular recesses are a favorable substrate for ventricular arrhythmias is unclear. Some reports have found that the fatal ventricular arrhythmias may occur in approximately half of the patients. In this report we investigated about this association. METHODS AND RESULTS: In total we evaluated a continuous series of 238 patients affected by non-compaction. Periodic Holter monitoring was performed every 6 months for 4 years. Only 11 patients had documented ventricular tachycardia, which was sustained in two cases and non-sustained in nine. In no cases we observed ventricular fibrillation. CONCLUSIONS: Non-compaction alone does not seem to be a risk factor for malignant ventricular arrhythmias.     

Echocardiographic Deformation Imaging for the Assessment of Left Ventricular Function: Clinical Implications and Perspectives— Update 2014

Echocardiographic deformation imaging is an emerging clinical method, which allows quantifying global and regional myocardial function. Its potential has been demonstrated in a large number of research settings, and it is now approaching routine clinical practice. This review provides an update on the recent developments in the field of deformation imaging and highlights current and potential future clinical applications of this promising technique.