C. Hsieh

Direct Transthoracic Access to the Left Ventricle for Catheter Ablation of Ventricular Tachycardia

Background—Percutaneous approaches for radiofrequency ablation of ventricular tachycardia (VT) in the left ventricle are typically transarterial retro-aortic, antegrade transmitral via an interatrial septal puncture, or epicardial. However, all 3 approaches may be contraindicated in certain cases. We describe 2 cases of VT ablation in which aortic and mitral valve replacements did not permit utilization of any of these techniques. Methods and Results—Direct access to the left ventricular cavity was achieved with a percutaneous puncture through the intercostal space overlying the apex in the first case and through a left minithoracotomy in the second. A sheath was then inserted via the Seldinger technique, allowing catheter access for mapping and ablation of the VT. After successful ablation, the sheaths were withdrawn and hemostasis was achieved. A large left hemothorax occurred from the left ventricular apical puncture in the first case. Direct closure with a purse-string suture in the second case achieved hemostasis. Conclusions—Direct percutaneous left ventricular puncture is a viable option for mapping and ablation of left ventricular VT. A minithoracotomy allows better hemostatic control. This technique has a role when other percutaneous approaches are contraindicated.

Evolution of Ventricular Tachycardia and Its Electrophysiological Substrate Early After Myocardial Infarction: An Ovine Model

Background— Sudden arrhythmic death after myocardial infarction (MI) is most frequent in the first month. Early programmed ventricular stimulation (within 1 week) post-MI has been able to identify long-term ventricular tachycardia (VT) occurrence. We aimed to determine the timing of development and stabilization of VT circuits after MI and how the evolution of the underlying substrate differs with VT inducibility. Methods and Results— MIs were induced in 36 sheep. The 21 survivors underwent serial electroanatomic mapping and programmed ventricular stimulation. Animals were classified as VTpos (inducible VT) or VTneg (noninducible VT) at day 8. Forty-three percent of MI survivors were VTpos on day 8 (9/21), and all remained inducible on day 100 with 1.5 (1.0–2.0) and 1.0 (1.0–2.0) morphologies per animal on days 8 and 100, respectively. Twelve-lead electrocardiogram matched in 15 of 19 VTs between days 8 and 100. The earliest presystolic ventricular activations during VT circuits were in similar locations at the 2 time points. The 12 VTneg animals remained noninducible on day 100. There was no difference in voltage or velocity substrate with time or inducibility. The area with fractionated signals increased with time and VT inducibility. VTpos animals had more linear regions of slowed conduction forming conducting channels. Conclusions— The inducibility and earliest presystolic endocardial activation sites of VT as well as voltage and velocity substrate on day 8 predicted those on day 100 postinfarct, indicating early formation and stabilization of the arrhythmogenic substrate. VT inducibility was influenced by the distribution of conducting channels and increased complex fractionated signals.

Prognostic Impact of Q Waves on Presentation and ST Resolution in Patients With ST-Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

Q waves can develop early in infarction and indicate infarct progression better than symptom duration. ST resolution (STR) is a predictor of reperfusion success. Our aim was to assess the prognostic impact of Q waves on presentation and STR after primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction. The combined end point was of mortality and adverse cardiovascular events (MACE; death, repeat myocardial infarction, or heart failure). Q waves on presentation (Q wave, n = 332; no Q wave, n = 337) was associated with significantly less mean STR, greater incidence of akinetic, dyskinetic, or aneurysmal regional wall motion, lower left ventricular ejection fraction, and worse in-hospital and 1-year MACEs (1 year 24% vs 8.2%, p <0.001). In addition, Q waves on presentation compared to no Q waves were associated with worse 1-year MACE regardless of infarct presentation in < or =3 hours, infarct location, and adequate STR (> or =70%). Q waves on presentation and inadequate STR (<70%), but not symptom duration, were independent predictors of MACE by multivariable analysis (adjusted hazard ratios of 2.7 and 2.4 for Q waves and STR, respectively). Compared to group A (no Q waves on presentation with STR), patients in group B (no Q waves with inadequate STR), group C (Q waves with STR), and group D (Q waves with inadequate STR) had hazard ratios of 3.0, 3.6, and 7.7, respectively (p <0.05) for the occurrence of MACE. In conclusion, assessment of Q-wave status on presentation and STR immediately after PPCI provides a simple and early clinical predictor of outcomes in ST-elevation myocardial infarction.

Case of coronary perforation with epicardial access for ablation of ventricular tachycardia

v fl T Introduction Epicardial access for electrophysiologic mapping and ablation has become more widely used, especially for ventricular tachycardia (VT). The major complications related to this form of access have been described and include entry into either ventricle and intraabdominal bleeding. In this report, we describe the complication of laceration of a coronary artery causing persistent pericardial bleeding and subsequent successful treatment by percutaneous coronary intervention obviating the need for emergency cardiac surgery.

Predictive Value of ST Resolution Analysis Performed Immediately Versus at Ninety Minutes After Primary Percutaneous Coronary Intervention

ST segment resolution (STR) predicts epicardial and microvascular reperfusion after primary percutaneous coronary intervention (PPCI) or thrombolysis for ST-elevation myocardial infarction. Immediate restoration of epicardial coronary flow, with improved microvascular perfusion, is much more likely with PPCI. However, the predictive value of immediate STR compared to 90 minutes after PPCI remains unknown. In 622 consecutive patients with ST-elevation myocardial infarction (mean age 59 +/- 13 years), 217 had complete STR immediately after PPCI (group A), 188 had complete STR only at 90 minutes (group B), and 217 had incomplete STR at either point (group C). The primary end point was mortality and adverse cardiovascular events ([MACE] death, nonfatal repeat myocardial infarction, and heart failure). Group A had a greater left ventricular ejection fraction (53%, 47%, and 46%, p <0.001) and lower all-cause mortality (1.8%, 3.2%, and 6%, p = 0.07), lower heart failure (1.8%, 4.3%, and 7.8%, p <0.001), and MACE (5.1%, 9.6%, and 16.1%, p = 0.001) at 30 days compared to groups B and C, respectively. The rate of MACE at 1 year was 7.6%, 17.1%, and 20.2% in groups A, B, and C, respectively (p <0.001). Immediate STR independently predicted MACE (adjusted hazard ratio 0.36, 95% confidence interval 0.21 to 0.61, p = 0.001, group A vs C), and STR at 90 minutes did not. In conclusion, STR analysis performed immediately after PPCI provided superior differentiation for adverse cardiovascular events compared to STR at 90 minutes. Immediate STR should be the contemporary goal of reperfusion with PPCI.

Primary Radiofrequency Ablation of Ventricular Tachycardia Early After Myocardial Infarction Evaluation in an Ovine Model

Background—Ventricular tachycardia (VT) is a significant complication of myocardial infarction. Radiofrequency ablation for postinfarct VT is reserved for drug refractory VT or VT storms. Our hypothesis is that radiofrequency ablation in the early postinfarct period could abolish or diminish late recurrences of VT. Methods and Results—Myocardial infarct was induced by balloon occlusion of the left anterior descending artery in 35 sheep. The 25 survivors underwent programmed ventricular stimulation and electroanatomical mapping 8 days postinfarct. Animals with inducible VT (12 out of 25 animals) underwent immediate radiofrequency ablation. Further VT inductions were performed 100 and 200 days postinfarct. At day 8, 3.0±0.9 VT morphologies per animal were inducible. All were successfully ablated with 24±6 applications of radiofrequency energy. All had ablations on the left ventricular endocardium, and 67% had ablations on the right ventricular aspect of the interventricular septum. All targeted arrhythmias were successfully ablated acutely. One animal was euthanized because of hypotension from a serious pericardial effusion. The other 11 survived and remained arrhythmia free on subsequent inductions on the 100th and 200th days (P<0.001). The 13 animals without inducible VT remained noninducible at the subsequent studies. A historical control arm of 9 animals with inducible VT at day 8 remained inducible at day 100. Conclusions—Radiofrequency ablation on the eighth day after infarction abolished inducibility of VT at late induction studies ⩽200 days in an ovine model. Early identification and ablation of VT after infarction may prevent or reduce late ventricular arrhythmias but needs to be validated in clinical studies.

Prognostic implication of ST‐segment resolution following primary percutaneous transluminal coronary angioplasty for ST‐elevation acute myocardial infarction

Background : ST‐segment changes have been shown to correlate with myocardial tissue perfusion. Complete ST‐segment resolution after thrombolysis in acute myocardial infarction is associated with lower mortality and better left ventricular function. Primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction restores better epicardial coronary flow to the infarct‐related artery than thrombolysis. However, ST changes may persist and flow can remain poor despite a patent vessel.

Circumflex coronary artery to left atrium fistula caused by mitral isthmus ablation.

Mitral isthmus ablation is an important component of catheter ablation for persistent atrial fibrillation and mitral isthmus dependent flutters. We describe a case where mitral isthmus ablation caused a fistula between the left circumflex artery and the left atrium and symptomatic ischaemia. The fistula was successfully closed with a covered stent.

Primary Radiofrequency Ablation of Ventricular Tachycardia Early After Myocardial InfarctionClinical Perspective: Evaluation in an Ovine Model

Background—Ventricular tachycardia (VT) is a significant complication of myocardial infarction. Radiofrequency ablation for postinfarct VT is reserved for drug refractory VT or VT storms. Our hypothesis is that radiofrequency ablation in the early postinfarct period could abolish or diminish late recurrences of VT. Methods and Results—Myocardial infarct was induced by balloon occlusion of the left anterior descending artery in 35 sheep. The 25 survivors underwent programmed ventricular stimulation and electroanatomical mapping 8 days postinfarct. Animals with inducible VT (12 out of 25 animals) underwent immediate radiofrequency ablation. Further VT inductions were performed 100 and 200 days postinfarct. At day 8, 3.0±0.9 VT morphologies per animal were inducible. All were successfully ablated with 24±6 applications of radiofrequency energy. All had ablations on the left ventricular endocardium, and 67% had ablations on the right ventricular aspect of the interventricular septum. All targeted arrhythmias were successfully ablated acutely. One animal was euthanized because of hypotension from a serious pericardial effusion. The other 11 survived and remained arrhythmia free on subsequent inductions on the 100th and 200th days (P<0.001). The 13 animals without inducible VT remained noninducible at the subsequent studies. A historical control arm of 9 animals with inducible VT at day 8 remained inducible at day 100. Conclusions—Radiofrequency ablation on the eighth day after infarction abolished inducibility of VT at late induction studies ⩽200 days in an ovine model. Early identification and ablation of VT after infarction may prevent or reduce late ventricular arrhythmias but needs to be validated in clinical studies.

Primary Radiofrequency Ablation of Ventricular Tachycardia Early After Myocardial InfarctionClinical Perspective

Background—Ventricular tachycardia (VT) is a significant complication of myocardial infarction. Radiofrequency ablation for postinfarct VT is reserved for drug refractory VT or VT storms. Our hypothesis is that radiofrequency ablation in the early postinfarct period could abolish or diminish late recurrences of VT. Methods and Results—Myocardial infarct was induced by balloon occlusion of the left anterior descending artery in 35 sheep. The 25 survivors underwent programmed ventricular stimulation and electroanatomical mapping 8 days postinfarct. Animals with inducible VT (12 out of 25 animals) underwent immediate radiofrequency ablation. Further VT inductions were performed 100 and 200 days postinfarct. At day 8, 3.0±0.9 VT morphologies per animal were inducible. All were successfully ablated with 24±6 applications of radiofrequency energy. All had ablations on the left ventricular endocardium, and 67% had ablations on the right ventricular aspect of the interventricular septum. All targeted arrhythmias were successfully ablated acutely. One animal was euthanized because of hypotension from a serious pericardial effusion. The other 11 survived and remained arrhythmia free on subsequent inductions on the 100th and 200th days (P<0.001). The 13 animals without inducible VT remained noninducible at the subsequent studies. A historical control arm of 9 animals with inducible VT at day 8 remained inducible at day 100. Conclusions—Radiofrequency ablation on the eighth day after infarction abolished inducibility of VT at late induction studies ⩽200 days in an ovine model. Early identification and ablation of VT after infarction may prevent or reduce late ventricular arrhythmias but needs to be validated in clinical studies.