Sajad Gulamhusein

Acceleration of the ventricular response during atrial fibrillation in the Wolff-Parkinson-White syndrome after verapamil.

We examined the electrophysiologic effects of verapamil in eight patients with the Wolff-Parkinson-White syndrome. Verapamil shortened the antegrade effective refractory period of the accessory pathway in three patients and abbreviated the shortest cycle length with 1:1 conduction over the accessory pathway in two patients. More significantly, verapamil decreased the shortest RR interval between preexcited ventricular complexes during atrial fibrillation (279 ± 20 msec vs 236 ± 18 msec, mean ± SEM; p < 0.01). After verapamil, two patients required cardioversion for hemodynamic deterioration after acceleration of the ventricular response during atrial fibrillation. In the four patients with predominantly preexcited ventricular complexes during atrial fibrillation the ventricular rate accelerated after verapamil, whereas in patients with predominantly normal ventricular complexes, the average ventricular rate decreased or did not change after verapamil. Verapamil may result in significant acceleration of ventricular response during atrial fibrillation in the Wolff-Parkinson-White syndrome. The safety of verapamil in individual patients with the Wolff-Parkinson-White syndrome should be established by electrophysiologic testing before its use.

Value and limitations of clinical electrophysiologic study in assessment of patients with unexplained syncope

We assessed the value of clinical electrophysiologic study using intracardiac recording and programed electrical stimulation in 34 patients who had unexplained syncope and/or presyncope. All patients had normal electrocardiograms, and no abnormality was detected by clinical examination, ambulatory electrocardiographic recording, or treadmill testing. The electrophysiologic results were diagnostic in four patients (11.8 percent) and led to appropriate therapy that totally relieved symptoms. The results were abnormal but not diagnostic in two patients (5.8 percent) and normal in the remaining 28 patients (82.4 percent). The patients were followed for a mean period of 15 months (range two to 44) after electrophysiologic testing. Sixteen patients (47 percent) had no further episodes in the absence of any intervention. In four patients (11.8 percent), a definitive diagnosis was made during follow-up. In seven patients, permanent pacing was instituted empirically with relief of syncope. Two patients continued to have syncopal spells. We conclude that the diagnostic yield of electrophysiologic testing is low in a patient population that has no electrocardiographic abnormality or clinical evidence of cardiac disease. Empirical permanent pacing in patients with symptoms continuing after our study appeared to be beneficial, but this result is difficult to evaluate because of the high incidence of spontaneous remission in this group. Persistent attempts to document electrocardiographic abnormalities during a typical episode of symptoms appears to be the only definitive way to confirm or exclude an arrhythmic cause of the symptoms.

Arrhythmogenic right ventricular dysplasia: a generalized cardiomyopathy?

Arrhythmogenic right ventricular dysplasia (ARVD)isa recently described entity characterized byright ventricular myopathic changes andright ventricular tachycardia. Thepresenceor extentofleft ventricular dysfunction inARVD isnotknown. We assessed right ventricular andleft ventricular function andsize insixpatients withARVDbyechocardiography andradionuclide angio- cardiography doneinpatients atrestandduring exercise. Allpatients hadrecurrent ventricular tachycardia ofleft bundle branch blockmorphology, andright ventricular origin oftheventricular tachycardia was confirmed byendocardial mapping infourpatients. Theresults werecompared with those of10normal subjects andfive patients withWolff-Parkinson-White syndrome taking amiodar- one.Thelatter group was a control group,since we didnotwithhold amiodarone therapy infour patients withARVD.Mean(+ SD)right ventricular ejection fraction (EF)inpatients withARVD was 25+ 11%atrestand26 12%during exercise. Innormal subjects right ventricular EFwas 51+ 4% atrestand59 6% during exercise (p .05). Innormal subjects, left ventricular EFwas 61+ 4%atrest and72 5%during exercise (p .05) tothose of normal subjects. We conclude that right ventricular dysfunction predominates inpatients withARVD butlatent left ventricular dysfunction ispresent more often thaniscommonly recognized. These findings may haveimportant diagnostic andtherapeutic implications. Circulation 68,No.2,251-257, 1983.

Intermittent preexcitation in the Wolff-Parkinson-White syndrome.

Intermittent loss of the delta wave in the Wolff-Parkinson-White (WPW) syndrome may result from precarious conduction over the accessory pathway and, as such, would predict a benign prognosis in the event of the occurrence of atrial fibrillation (AF). We evaluated 52 consecutive patients referred for the assessment of the WPW syndrome and determined the prevalence of intermittent preexcitation using review of serial electrocardiograms, ambulatory monitoring, and treadmill testing. All patients subsequently had electrophysiologic testing using standard techniques to determine the properties of the accessory pathway. Of the 52 patients, 26 (50%) were found to have intermittent preexcitation as defined by loss of the delta wave with concomitant prolongation of the P-R interval on at least 1 occasion. These patients had longer effective refractory periods of the accessory pathway (356 +/- 114 versus 295 +/- 29 ms, mean +/- standard deviation, p less than 0.05) and longer shortest cycle lengths maintaining 1:1 anterograde conduction (426 +/- 171 versus 291 +/- 63 ms, p less than 0.02) than their counterparts with constant preexcitation. During AF, 15% of patients with intermittent preexcitation had shortest R-R intervals between preexcited beats less than 250 ms, versus 50% of patients with constant preexcitation (p less than 0.01). These data support the hypothesis that intermittent preexcitation suggests a benign prognosis in the event of AF. A careful search for intermittent preexcitation may yield important prognostic information in asymptomatic subjects and obviate further investigation.

Postpacemaker implant pericarditis: incidence and outcomes with active-fixation leads.

SIVAKUMARAN, S., et al.: Postpacemaker Implant Pericarditis: Incidence and Outcomes with Active Fixation Leads. Pericarditis has been noted as a potential complication of pacemaker implantation. This study evaluated the risk of developing pericarditis following pacemaker implantation with active‐fixation atrial leads. Included were 1,021 consecutive patients (mean age 73.4 ± 0.4 years, range 16–101 years; 45.2% women) undergoing new pacemaker system implantation between 1991 and 1999 who were reviewed for the complication of pericarditis. The incidence and outcomes of postimplantation pericarditis in patients receiving active‐fixation atrial leads were compared to those not receiving these leads. Of 79 patients who received active‐fixation atrial leads, 4 (5%) developed pericarditis postpacemaker implantation. Of 942 patients with passive‐fixation atrial leads or no atrial lead (i.e., a ventricular lead only), none developed pericarditis postoperatively (P < 0.001). Of patients receiving active‐fixation ventricular leads only (n = 97), none developed pericarditis. No complications were apparent at the time of implantation in patients who developed pericarditis. Pleuritic chest pain developed between 1 and 28 hours postoperatively. Three patients had pericardial rubs without clinical or echocardiographic evidence of tamponade. They were treated conservatively with acetylsalicylic acid or ibuprofen and their symptoms resolved without sequelae in 1–8 days. One patient (without pericardial rub) died due to cardiac tamponade on postoperative day 6. Postmortem examination revealed hemorrhagic pericarditis with no gross evidence of lead perforation. Pericarditis complicates pacemaker implantation in significantly more patients who receive active‐fixation atrial leads. It may be precipitated by perforation of the atrial lead screw through the thin atrial wall. Patients developing postoperative pericarditis should be followed closely due to the risk of cardiac tamponade.

Low energy counterchock using an intravascular catheter in an acute cardiac care setting

We examined the feasibility, effectiveness, and safety of using an intravascular catheter positioned in the right ventricular apex for countershock in a coronary care unit setting in 8 patients who had recurrent ventricular tachyarrhythmia. Countershock using 2.5 to 40 J stored energy (damped sinusoidal wave form) was attempted 115 times to terminate 100 episodes of ventricular tachyarrhythmia (ventricular tachycardia, 91; ventricular flutter, 3; ventricular fibrillation, 6). Eighty-six (87%) of 99 countershock attempts for ventricular tachycardia, 3 (60%) of 5 for ventricular flutter, and 4 (36%) of 11 for ventricular fibrillation were successful using this technique. The catheters remained in stable position for 1 to 16 days without dislodgment. A majority of the countershocks were delivered by the regular nursing staff in the coronary unit. We conclude that low energy countershock through an intravascular catheter system is feasible, safe, and effective in a coronary care unit setting. Such a system should be beneficial in the acute management of patients who have recurrent ventricular tachycardia or fibrillation. The catheter lead may also prove useful in managing ventricular tachyarrhythmias that occur during electrophysiologic studies.

Comparison of the electrophysiologic effects of intravenous and oral verapamil in patients with paroxysmal supraventricular tachycardia

The electrophysiologic effects of intravenous verapamil (a bolus dose of 0.15 mg/kg body weight followed by infusion of 0.005 mg/kg per min) were compared with those of oral verapamil (80 mg every 6 hours for 48 hours) in eight patients who had paroxysmal supraventricular tachycardia. The mechanism of tachycardia was atrioventricular (A-V) nodal reentry in four patients and A-V reentry utilizing an accessory pathway for retrograde conduction in the remaining four. The electrophysiologic effects of oral and intravenous verapamil were similar. Both preparations significantly prolonged anterograde effective and functional refractory periods of the A-V node (p less than 0.001). Both significantly increased the shortest pacing cycle length maintaining 1:1 anterograde conduction over the A-V node (p less than 0.001). Retrograde conduction over the A-V node was greatly prolonged with verapamil in one patient but was unaffected in the others. There was no significant effect on sinoatrial conduction time, sinus nodal recovery time or atrial or ventricular refractoriness. Both preparations prevented induction of tachycardia in six patients none of whom had recurrence of sustained tachycardia while receiving long-term oral therapy (5 to 10 months). Neither preparation had a significant effect in two patients and this predicted failure of long-term oral therapy in one of these patients. The results of acute drug testing with intravenous verapamil can be extrapolated to predict the electrophysiologic results and response to long-term therapy with oral verapamil.

Atrioventricular dissociation during paroxysmal junctional tachycardia.

We describe the rare occurrence of atrioventriculor dissociation in three patients during paroxysmal functional tachycardia. The mechanism of tachycardia was atrioventricular nodal reentry in two patients. The third patient had reentrant tachycardia that utilized the A V node for at least part of the reentrant circuit. This patient also had a nodoventricular pathway that may have participated in the reentrant circuit. In two patients, ventricular tachycardia was diagnosed prior to electrophysiologic assessment and medication to prevent tachycardia was not successful. After electrophysiological studies, treatment directed at suppressing AV nodel reentry prevented recurrent tachycardia. These case studies demonstrate the importance of detailed electrophysiological assessment of tachycardia in patients whose arrhythmia does not respond to empirical antiarrhythmic therapy. (PACE, Vol. 4, November‐December, 1981)

Feasibility of direct discharge from the coronary/intermediate care unit after acute myocardial infarction

OBJECTIVES This investigation was designed to determine the feasibility and cost-effectiveness of direct discharge from the coronary/intermediate care unit (CICU) in 497 consecutive patients with an acute myocardial infarction (AMI). BACKGROUND Although patients with an AMI are traditionally treated in the CICU followed by a period on the medical ward, the latter phase can likely be incorporated within the CICU. METHODS All patients were considered for direct discharge from the CICU with appropriate patient education. The 6-week postdischarge course was evaluated using a structured questionnaire by a telephone interview. RESULTS There were 497 patients (men = 353; women = 144; age 63.5 +/- 0.6 years) in the study, with 29 in-hospital deaths and a further 11 deaths occurring within 6 weeks of discharge. The mode length of CICU stay was 4.0 days (mean 5.1 +/- 0.2 days): 1 to 2 (12%), 3 (19%), 4 (21%), 5 (14%), 6 to 7 (19%) and > or = 7 (15%) days, respectively with 87.2% discharged home directly. Of the 425 patients surveyed, 119 (28.0%) indicated that they had made unscheduled return visits (URV) to a hospital or physicians office: 10.6% to an emergency room, 9.4% to a physicians office and 8.0% readmitted to a hospital. Of these URV, only 14.3% occurred within 48 h of discharge. Compared to historical controls, the present management strategy resulted in a cost savings of Cdn.

Combined verapamil and propranolol for supraventricular tachycardia

4,044.01 per patient. CONCLUSIONS Direct discharge from CICU is a feasible and safe strategy for the majority of patients that results in considerable savings.