Sudden unexpected death, epilepsy and familial cardiac pathology.

We evaluated the prevalence of epilepsy in a cohort of patients who suffered a sudden unexpected death (SUDEP), and determined the proportion of the deaths that were related to an identifiable underlying familial cardiac pathology. Epilepsy is common in people who experience a sudden unexpected death, with approximately a quarter having identifiable familial electrophysiological abnormalities. Familial cardiac pathology may be an important cause of SUDEP. A retrospective evaluation was performed of 74 families that were referred to the Royal Melbourne Hospital Cardiac Genetic Clinic over a 5 year period for investigation following a family member's sudden, presumed cardiac, death. This state-wide referral clinic includes all patients who have died from a sudden unexpected death in whom the cause of death is unascertained. An epilepsy diagnosis was categorised as either definite, probable, possible or unlikely. The family members underwent comprehensive clinical evaluations and investigations in an attempt to identify a familial cardiac cause for the sudden unexpected death. Our findings suggest that systematic referral to a cardiac genetics service is warranted for the first degree relatives of people with epilepsy who experience a sudden unexplained death, for further evaluation and to identify those who are at higher risk for sudden death. Interventions may then be instituted to potentially reduce this risk.

Pulmonary vein antral isolation for paroxysmal atrial fibrillation: results from long-term follow-up.

INTRODUCTION: Pulmonary veins play an important role in triggering atrial fibrillation (AF). Pulmonary vein isolation (PVI) is an effective treatment for patients with paroxysmal AF. However, the late AF recurrence rate in long-term follow-up of circumferential PV antral isolation (PVAI) is not well documented. We sought to determine the time to recurrence of arrhythmia after PVAI, and long-term rates of sinus rhythm after circumferential PVAI. METHODS: One hundred consecutive patients with a mean age of 54 ± 10 years, with paroxysmal AF who underwent PVAI procedure were analyzed. Isolation of pulmonary veins was based on an electrophysiological and anatomical approach, with a nonfluoroscopic navigation mapping system to guide antral PVI. Ablation endpoint was vein isolation confirmed with a circular mapping catheter at first and subsequent procedures. Clinical, ECG, and Holter follow-up was undertaken every 3 months in the first year postablation, every 6 months thereafter, with additional prolonged monitoring if symptoms were reported. Time to arrhythmia recurrence, and representing arrhythmias, were documented. RESULTS: Isolation of all 4 veins was successful in 97% patients with 3.9 ± 0.3 veins isolated/patient. Follow-up after the last RF procedure was at a mean of 39 ± 10 months (range 21-66 months). After a single procedure, sinus rhythm was maintained at long-term follow-up in 49% patients without use of antiarrhythmic drugs (AADs). After repeat procedure, sinus rhythm was maintained in 57% patients without the use of AADs, and in 82% patients including patients with AADs. A total of 18 of 100 patients had 2 procedures and 4 of 100 patients had 3 procedures for recurrent AF/AT. Most (86%) AF/AT recurrences occurred ≤ 1 year after the first procedure. Mean time to recurrence was 6 ± 10 months. Kaplan-Meier analysis on antiarrhythmics showed AF free rate of 87% at 1 year and 80% at 4 years. There were no major complications. CONCLUSION: PVAI is an effective strategy for the prevention of AF in the majority of patients with PAF. Maintenance of SR requires repeat procedure or continuation of AADs in a significant proportion of patients. After maintenance of sinus rhythm 1-year post-PVAI, a minority of patients will subsequently develop late recurrence of AF.

Immediate and long-term results of radiofrequency ablation of pulmonary vein ectopy for cure of paroxysmal atrial fibrillation using a focal approach.

BACKGROUND: Atrial fibrillation (AF) is frequently initiated by focal activity originating in the pulmonary veins. We present the early and long-term results of a focal approach to pulmonary-vein ablation for cure of paroxysmal AF. AIMS: The aim of this study was to establish the effectiveness of focal pulmonary vein radiofrequency ablation (RFA) for cure of paroxysmal AF. METHODS: Fifty-one consecutive patients (35 male; 45+/-11.4 years) were considered for RFA on the following criteria: (i) symptomatic drug refractory AF, (ii) high-density atrial ectopy, bursts of atrial tachycardia or AF, (iii) absence of structural heart disease and (iv) provision of informed consent. Pulmonary vein mapping and RFA were by single trans-septal puncture, which was only performed in patients with adequate focal activity at the time of procedure. Focal activity was present spontaneously or was elicited by isoprenaline, burst pacing or AF induction and cardioversion. RESULTS: One patient was excluded from the analysis due to non-pulmonary vein triggers. Trans-septal mapping and RFA were not performed in 22 patients (44%) due to: (i) inadequate ectopy (17), (ii) recurrent AF (1), (iii) inability to cross septum (2) and (iv) multiple foci (2). Of 28 patients, RFA was attempted with procedural success in 23 patients (82%), with no acute complications. Mean fluoroscopy time for patients having RFA was 29+/-11.5 mins. Pulmonary vein stenosis occurred in one case. Ten patients had symptomatic recurrence and, of those, two had further RFA. At a mean follow up of 11+/-8 months, 15 patients (54% ablated, 30% of the total cohort) remained free of AF without antiarrhythmics. CONCLUSION: This series highlights the low long-term success rate of RFA to cure AF by targeting pulmonary vein initiators using a focal approach. Electrical pulmonary vein isolation may provide better long-term results.

Focal atrial tachycardia arising from the tricuspid annulus: electrophysiologic and electrocardiographic characteristics.

INTRODUCTION: Focal right atrial tachycardia (RAT) arising from the crista terminalis, para-Hisian, and coronary sinus os regions are well described. Less information exists regarding RAT arising from the nonseptal region of the tricuspid annulus (TA). METHODS AND RESULTS: From a consecutive series of 64 patients who had undergone successful radiofrequency ablation (RFA) of 67 RATs, the characteristics of 9 (13%) patients (6 men; mean age 50 +/- 20 years) with a TA focus were reviewed. The annular focus was localized to the inferoanterior TA in 7 and the superior TA in 2. Mean tachycardia cycle length was 371 +/- 66 msec. Mean activation time at the site of successful RFA in 9 of 9 patients was -43 +/- 11 msec. At 9.3 +/- 5.6 months of follow-up, 1 of 9 patients had recurrent tachycardia successfully treated with repeat RFA. In 7 of 9 patients with RAT from the inferoanterior TA, the surface ECG P wave morphology was upright in aVL, inverted in III and VI, and either inverted or biphasic with an initial negative deflection from V2 to V6. CONCLUSION: The TA is an important site of origin of RAT. In the present study, the inferoanterior region of the TA was a preferential site of origin with resulting characteristic P wave morphology. Knowledge of this anatomic distribution and P wave morphology allows targeted mapping and may facilitate successful RFA.

Electrical remodeling of the atria associated with paroxysmal and chronic atrial flutter.

BACKGROUND: Atrial electrical remodeling may be important for the initiation and perpetuation of atrial arrhythmias. Whether paroxysmal atrial flutter (AFL) and chronic AFL cause electrical remodeling of the atria has not been conclusively determined. METHODS AND RESULTS: Before radiofrequency ablation of paroxysmal AFL, 15 patients in sinus rhythm were evaluated under autonomic blockade. Lateral right atrial (LRA) effective refractory periods (ERPs) at 600 and 450 ms were measured before and at 1-minute intervals for 10 minutes after spontaneous or pace termination of a 5- to 10-minute period of induced AFL. In 10 patients with chronic AFL, LRA, septal, and coronary sinus (CS) ERPs and corrected sinus node recovery times (cSNRTs) at 600 and 450 ms were measured under autonomic blockade 15 minutes, 30 minutes, and 3 weeks after termination of chronic AFL by ablation. In the paroxysmal AFL group, LRA ERPs decreased by 18% at 600 ms and 12% at 450 ms (P:<0.01) after induced AFL and recovered to baseline over approximately 5 minutes. Atrial fibrillation developed during AFL in 3 patients and during ERP testing in 3 patients when refractoriness was at its nadir. In the chronic AFL group, LRA, septal, and CS ERPs at 3 weeks were significantly greater than at 15 and 30 minutes after termination of chronic AFL at both cycle lengths (P:<0.01). Three weeks after ablation, cSNRT decreased 35% at 600 ms (P:<0.05) and decreased 44% at 450 ms (P:<0. 05). Both ERPs and cSNRTs measured 15 and 30 minutes after ablation of chronic AFL were not significantly different. CONCLUSIONS: Both paroxysmal AFL and chronic AFL cause reversible electrical remodeling of the atria but demonstrate different time courses of recovery.

Electrical remodeling of the atria following loss of atrioventricular synchrony: a long-term study in humans.

BACKGROUND: Evidence suggests that an increased incidence of atrial fibrillation occurs in patients undergoing single-chamber ventricular pacing (VVI) when compared with those undergoing single-chamber atrial pacing (AAI) or those having dual-chamber atrioventricular pacing (DDD). The mechanism for this is unknown. We hypothesized that long-term loss of atrioventricular (AV) synchrony leads to atrial electrical remodeling: a potential explanation for this difference. METHODS AND RESULTS: The study was a prospective, randomized comparison between 18 patients paced in VVI mode and 12 patients paced in DDD mode for 3 months. Under autonomic blockade, effective refractory periods (ERPs) from the lateral right atrium (RA), RA appendage, RA septum, and coronary sinus-corrected sinus node recovery times (cSNRTs), as well as P-wave duration (PWD), and biatrial diameters were measured at baseline and 3 months. The VVI group was then programmed to DDD pacing and reevaluated after a further 3 months. After long-term VVI pacing, ERPs at all 4 atrial sites increased significantly in a nonuniform fashion in association with biatrial dilatation. PWD and cSNRTs also prolonged significantly. With the reestablishment of AV synchrony, ERPs, PWD, cSNRTs, and biatrial dimensions returned to baseline levels. In the 12 patients who underwent long-term DDD pacing from baseline, no significant changes in atrial electrophysiology or biatrial dimensions were demonstrated. CONCLUSIONS: Long-term loss of AV synchrony induced by VVI pacing is associated with atrial electrical remodeling, which is reversible after the reestablishment of AV synchrony with DDD pacing. This process may be partly responsible for the higher incidence of atrial fibrillation in patients undergoing VVI pacing compared with AV sequential pacing.

Mechanical remodeling of the left atrium after loss of atrioventricular synchrony. A long-term study in humans.

BACKGROUND: Tachycardia-mediated mechanical remodeling of the atrium is considered central to the pathogenesis of thromboembolism associated with chronic atrial fibrillation. Whether atrial mechanical remodeling also occurs in response to atrial stretch induced by chronic asynchronous ventricular pacing in patients with permanent pacemakers is unknown. METHODS AND RESULTS: The study design was a prospective randomized comparison between 21 patients paced chronically in the VVI mode and 11 patients paced chronically in the DDD mode for 3 months. Left atrial appendage (LAA) function and the presence of spontaneous echo contrast (SEC) were determined with transesophageal echocardiography (TEE) within 24 hours of pacemaker implantation and after 3 months. The VVI patients were then programmed to DDD and underwent a third TEE after DDD pacing for an additional 3 months. After chronic VVI pacing, LAA velocity decreased from 82.4+/-29.0 to 42.1+/-25.4 cm/s (P<0.01), LAA fractional area change decreased from 74.9+/-17.2% to 49.8+/-22.0% (P<0.01), and 4 patients (19%) developed left atrial SEC (P<0.05). With the reestablishment of chronic AV synchrony, LAA velocity increased to 61.6+/-18.5 cm/s (P<0.01), LAA fractional area change increased to 76.4+/-18.1% (P<0.01), and SEC resolved. In the 11 patients undergoing chronic DDD pacing, no significant changes in LAA velocity (baseline, 86.0+/-28.8 cm/s versus 3 months, 79.6+/-14. 9 cm/s) or LAA fractional area change (baseline, 76.2+/-19.4% versus 72.5+/-15.7%) were demonstrated, and SEC did not develop. CONCLUSIONS: Chronic loss of AV synchrony induced by VVI pacing is associated with mechanical remodeling of the left atrium, which may reverse after the reestablishment of AV synchrony with DDD pacing. This process may be partly responsible for the higher incidence of thromboembolism observed in patients undergoing VVI pacing compared with AV sequential pacing.

Palpitations: reassurance or more?

Palpitations are a common symptom and are caused by forceful or rapid beating of the heart. Palpitations can be caused by a variety of cardiac arrhythmias and careful history is invaluable in deciding appropriate investigations and management. Palpitations caused by anxiety-induced sinus tachycardia are common, but anxiety is also common in patients who have cardiac arrhythmias for which effective treatment is available. Management of palpitations depends on the type of cardiac arrhythmia; almost all arrhythmias can now be effectively treated. Radiofrequency ablation provides an effective cure for most patients with paroxysmal supraventricular tachycardia when the alternative is continuous drug therapy.

Left atrial mechanical function after brief duration atrial fibrillation.

OBJECTIVES: This study examined the effect of brief duration atrial fibrillation on left atrial and left atrial appendage mechanical function in humans with structural heart disease. BACKGROUND: Left atrial dysfunction and the development of spontaneous echo contrast (SEC) may follow the cardioversion of atrial fibrillation (AF) to sinus rhythm. This phenomenon has been termed "stunning" and is implicated in the development of atrial thrombus and embolic stroke. The effects of brief duration AF on left atrial mechanical function in humans are unknown. METHODS: Twenty-four patients (23 men, aged 59.1+/-12.7 years) with significant structural heart disease (ejection fraction 31.2+/-9.0%, left atrial diameter 4.9+/-0.4 cm) undergoing implantation of a ventricular cardiodefibrillator underwent transesophageal echocardiography to evaluate left atrial appendage emptying velocities (LAAeV) and SEC before, during and after a 15-min period of AF induced by rapid right atrial pacing. Atrial fibrillation was then permitted to terminate spontaneously within 5 min or was reverted with an endocardial direct current shock. Velocities and SEC were assessed in sinus rhythm pre-AF, during AF and immediately, 5 and 10 min after reversion to sinus rhythm. RESULTS: Atrial fibrillation terminated spontaneously in 10 patients after 16.1+/-1.0 min. Endocardial direct current (DC) cardioversion of 10.4+/-6.4 J was required in 14 patients after AF lasting 20 min. Mean LAAeV pre-AF (50.0 +/- 17.5 cm/s) was not significantly different to LAAeV immediately (52.8 +/- 16.7 cm/s), 5 min (54.3 +/- 16.4 cm/s) or 10 min (53.7 +/- 15.7 cm/s) after reversion to sinus rhythm. Atrial stunning defined as a reduction in LAAeV of >20% was not observed in any patient. Fourteen of 24 patients (58%) developed SEC during AF, which resolved within 30 s of AF termination. There were no significant differences between LAAeV in those patients reverting with DC shock (pre-AF 50.6+/-16.2 cm/s vs. immediately post-AF 54.7+/-16.6 cm/s) or in those patients with spontaneous reversion (pre-AF 48.9+/-20.2 cm/s vs. immediately post-AF 49.8+/-17.3 cm/s). CONCLUSIONS: Significant left atrial stunning was not observed after brief duration AF in humans with structural heart disease. Transient left atrial SEC develops in a significant proportion of these patients during AF but resolves rapidly on reversion to sinus rhythm. These findings suggest that the risk of thromboembolism may be low after brief duration AF that terminates either spontaneously or with an endocardial DC shock even in patients with significant structural heart disease. These findings have important implications for recipients of implantable devices that are capable of atrial defibrillation in response to AF.

Left atrial "stunning" following radiofrequency catheter ablation of chronic atrial flutter.

OBJECTIVES: This study examined the effect of radiofrequency ablation (RFA) on left atrial (LA) and left atrial appendage (LAA) function in humans with chronic atrial flutter (AFL). BACKGROUND: Atrial stunning and the development of spontaneous echocardiographic contrast (SEC) is a consequence of electrical cardioversion of AFL to sinus rhythm. This phenomenon has been termed "stunning" and is associated with thrombus formation and embolic stroke. Radiofrequency ablation is now considered to be definitive treatment for chronic AFL, but whether this procedure is complicated by LA stunning is unknown. METHODS: Fifteen patients with chronic AFL undergoing curative RFA underwent transesophageal echocardiography to evaluate LA and LAA function and SEC before and immediately, 30 minutes and 3 weeks after RFA. To control for possible direct effects of RFA on atrial function, seven patients undergoing RFA for paroxysmal AFL were also studied. In this group, RF energy was delivered in sinus rhythm and echocardiographic parameters were assessed before and immediately and 30 minutes following RFA. RESULTS: Chronic AFL: Mean arrhythmia duration was 17.2 +/- 13.3 months. Twelve patients (80%) developed SEC following RF energy application and reversion to sinus rhythm. LAA velocities decreased significantly from 54.0 +/- 14.2 cm/s in AFL to 18.0 +/- 7.1 cm/s in sinus rhythm after arrhythmia termination (p < 0.01). These changes persisted for 30 minutes. Following 3 weeks of sustained sinus rhythm, significant improvements in LAA velocities (68.9 +/- 23.6 vs. 18.0 +/- 7.1 cm/s, p < 0.01) and mitral A-wave velocities (49.8 +/- 10.3 vs. 13.4 +/- 11.2 cm/s, p < 0.01) were evident and SEC had resolved in all patients. Paroxysmal AFL: Radiofrequency energy delivered in sinus rhythm had no significant effect on any of the above indexes of LA or LAA function and no patient developed SEC following RFA. CONCLUSIONS: Radiofrequency ablation of chronic AFL is associated with significant LA stunning and the development of SEC. Left atrial stunning is not secondary to the RF energy application itself. Sustained sinus rhythm for 3 weeks leads to resolution of these acute phenomena. Left atrial stunning occurs in the absence of direct current shock or antiarrhythmic drugs, suggesting that its mechanism may be a function of the preceding arrhythmia rather than the mode of reversion.

Effect of direct current shocks on left atrial mechanical function in patients with structural heart disease.

OBJECTIVES: This study examined the effect of endocardial and transthoracic direct current (DC) shocks on left atrial and left atrial appendage function in humans with structural heart disease. BACKGROUND: DC cardioversion of atrial fibrillation (AF) to sinus rhythm is associated with transient left atrial and left atrial appendage dysfunction and the development of spontaneous echo contrast (SEC). This phenomenon has been termed atrial "stunning" and may be associated with thrombus formation and embolic stroke. To what extent the shock itself contributes to atrial stunning is unclear. METHODS: Thirteen patients in sinus rhythm undergoing implantation of a ventricular implantable cardioverter defibrillator (ICD) were prospectively evaluated. All patients had significant structural heart disease. To evaluate the effects of DC shocks on left atrial and left atrial appendage function, biphasic R wave synchronized endocardial shocks of 1, 10 and 20 J were delivered between the right ventricular electrode and the left pectoral generator of the ICD in sinus rhythm. R wave synchronized transthoracic shocks of 360 J were also delivered between anteriorly and posteriorly positioned chest electrodes. Transesophageal echocardiography was performed to evaluate left atrial appendage velocities, mitral inflow velocities and the presence of SEC before and immediately after each DC shock. RESULTS: There were no significant changes in left atrial or left atrial appendage function after endocardial or transthoracic DC shocks. Left atrial SEC did not develop after endocardial or transthoracic DC shocks. CONCLUSIONS: Endocardial and transthoracic DC shocks are not directly responsible for left atrial and left atrial appendage stunning and do not contribute to the stunning that is observed after the cardioversion of AF to sinus rhythm.

Radiofrequency ablation for cure of atrial flutter.

BACKGROUND: Atrial flutter is a common arrhythmia which frequently recurs after cardioversion and is relatively difficult to control with antiarrhythmic agents. AIMS: To evaluate the success rate, recurrence rate and safety of radiofrequency, (RF) ablation for atrial flutter in a consecutive series of patients with drug refractory chronic or paroxysmal forms of the arrhythmia. METHODS: Electrophysiologic evaluation of atrial flutter included activation mapping with a 20 electrode halo catheter placed around the tricuspid annulus and entrainment mapping from within the low right atrial isthmus. After confirmation of the arrhythmia mechanism with these techniques, an anatomic approach was used to create a linear lesion between the inferior tricuspid annulus and the eustachian ridge at the anterior margin of the inferior vena cava. In order to demonstrate successful ablation, mapping techniques were employed to show that bi-directional conduction block was present in the low right atrial isthmus. RESULTS: Successful ablation was achieved in 26/27 patients (96%). In one patient with a grossly enlarged right atrium, isthmus block could not be achieved. Of the 26 patients with successful ablation, there has been one recurrence of typical flutter (4%) during a mean follow-up period of 5.5 +/- 2.7 months. This patient underwent a successful repeat ablation procedure. Of eight patients with documented clinical atrial fibrillation (in addition to atrial flutter) prior to the procedure, five continued to have atrial fibrillation following the ablation. There were no procedural complications and all patients had normal AV conduction at the completion of the ablation. CONCLUSIONS: RF ablation is a highly effective and safe procedure for cure of atrial flutter. In patients with chronic or recurrent forms of atrial flutter RF ablation should be considered as a first line therapeutic option.

Oral flecainide, sotalol, and verapamil for the termination of paroxysmal supraventricular tachycardia.

The ability to terminate supraventricular tachycardia (SVT) acutely with an oral dose of flecainide (2.5-3.3 mg/kg), sotalol (2.0-2.9 mg/kg), and verapamil (3.3-3.7 mg/kg) was investigated in an observational study of six patients with SVT normally controlled by an antitachycardia pacemaker. The pacemaker was programmed to induce SVT and the stability of SVT was observed for 90 minutes as a baseline. Subsequent studies involved testing of the three antiarrhythmic drugs on separate occasions, given in random order as crushed tablets in orange juice during pacemaker induced SVT, with plasma drug levels collected every 15 minutes for 90 minutes post drug ingestion. Sotalol produced drug induced slowing of SVT in all six patients, with termination of SVT in three patients by 60-65 minutes, with maximum plasma levels of 0.76-2.09 micrograms/mL achieved by 90 minutes. Flecainide produced maximum plasma levels of 83-745 ng/mL, 60-90 minutes post ingestion, and slowed SVT in three patients. SVT was terminated in three patients after 45-85 minutes, but no effect on SVT was seen in two patients who had inadequate plasma levels (< or = 166 ng/mL) from doses < 3 mg/kg. Verapamil produced maximum plasma levels of 0 (undetectable) to 388 ng/mL, 45-90 minutes post ingestion, and slowed SVT in three patients, but only one of these patients reverted to sinus rhythm (at 40 min). No effect on SVT was seen in three patients due to undetectable plasma levels. We concluded that sotalol (> or = 2 mg/kg) and flecainide (> or = 3 mg/kg) appeared to be suitable oral drugs for termination of SVT.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular dysfunction following direct-current shock atrioventricular junction ablation.

Catheter-induced His bundle ablation for refractory supraventricular arrhythmias is most commonly performed with direct-current shock energy of 200-300 joules. The high energy pulse delivered by direct-current shock produces a lesion in the atrioventricular node by fulguration, with the residual energy being dissipated as a pressure wave. The effect of direct-current shock His bundle ablation on global and regional ventricular function was assessed in 14 consecutive patients by radionuclide ventriculography performed before and after ablation and again three months later. All studies were performed with ventricular pacing at 110 bpm. Global left ventricular ejection fraction was found to be significantly reduced at the three month study (0.43 +/- 0.03 vs 0.50 +/- 0.03, pre ablation, p = 0.02). A significant reduction in wall-motion score was also seen in six of the seven patients who had normal wall motion in pacing rhythm prior to ablation. Deterioration was mainly seen at the left and right ventricular apices. The observed reduction in ventricular function that follows direct-current shock His bundle ablation may result from myocardial damage from electro-coagulation or from barotrauma and supports continued investigation into alternative, less traumatic energy sources for the procedure.

Short- and long-term results of transvenous catheter ablation of the atrioventricular conduction system.

Twenty-two patients with refractory supraventricular arrhythmias were treated by catheter-delivered high-energy shocks to the atrioventricular conduction system. All patients had a minimum follow-up period of six months (mean +/- SD, 15 +/- 9 months), at which time 21 of the 22 patients were free of symptoms and required no antiarrhythmic therapy. Permanent pacemakers were implanted in all patients. These results show that transvenous ablation or modification of atrioventricular conduction is a safe and effective technique to treat a wide range of supraventricular arrhythmias, and obviates the need for open-heart surgery for the interruption of atrioventricular nodal conduction.

Arrhythmogenic right ventricular dysplasia. Clinical, electrophysiological, and pathological features.

Arrhythmogenic right ventricular dysplasia (ARVD) describes the syndrome of recurrent ventricular tachycardia of right ventricular origin and cardiomyopathic changes of the right ventricle. We report the clinical, electrophysiologic, and angiographic characteristics of four patients who presented with ventricular tachycardia of left bundle branch block configuration, and in whom the right ventricular origin of tachycardia was confirmed by endocardial mapping, and a diagnosis of ARVD was substantiated by histological examination. ARVD should be suspected in all patients with ventricular tachycardia of left bundle branch block configuration, especially in young adults with an otherwise normal heart. Once suspected, diagnosis can often be established by non-invasive investigation. Surgical treatment may be difficult because of the diffuse nature of right ventricular involvement.

Ventricular tachycardia and sudden death in myotonic dystrophy: clinical, electrophysiologic and pathologic features.

A 37 year old man who presented with a cardiomyopathy, conduction defects and atrial and ventricular arrhythmias was found to have the neuromuscular manifestations of myotonic dystrophy. Despite implantation of a permanent cardiac pacemaker, antiarrhythmic drug therapy and antiarrhythmic surgery, sudden death occurred. The results of electrophysiologic studies, coronary arteriography and pathologic findings are described. This case confirms previous observations that ventricular arrhythmias, in addition to atrial arrhythmias and conduction disturbances, are cardiac manifestations of myotonic dystrophy and can lead to sudden death.

Multiform ventricular tachycardia.

Electrophysiological studies were performed in three patients with chronic recurrent ventricular tachycardia (VT) associated with coronary artery disease. In each case the ventricular origin of the tachycardia was confirmed and induction of tachycardia by programmed stimulation suggested a re-entry mechanism. Multiple types of ventricular tachycardia were observed which differed in cycle length, QRS morphology, timing of local epicardial and endocardial ventricular electrograms and the use of the specialized conduction system for propagation. There was evidence of one or more re-entry circuits arising in or near previously infarcted areas, with features of cycle length alternation, change in exit points and variations in subsequent conduction through the myocardium and specialized conduction tissues. These findings suggest multiform VT can be due to a number of factors. A modified surgical approach is recommended for management of medically refractory VT when there is evidence of multiple types.